The HSB CT Engineering Services Division Manual par. 4541 (4)(a)&(b) requires the
Authorized Inspector Supervisor to conduct "Periodic inspector meetings to discuss all aspects of
ASME Code Inspection", and to have "technical discussions annually". So, every once in a while
I send out questions with answers and paste them into an email. Keep in mind these are just
opinions and if you have specific questions please direct them to one of the Supervisors.
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VIII Div 1: U-1(c)(2)(j) 3,000 psi Limit:
VIII-1, UG-99(g) No Leakage during Hydro Inspection
VIII Div 1, UHA -51 High Alloy steel impacts?
P-3A Data Report
VIII-1, UG-44 and B16.9 and B16.11 Fittings
Power Boiler field hydro
Section IV Test Pressure requirements
Changing bolts after hydrotest - UG-99(g)
Section I, PG-109.3 - PP Stamping Scope
VIII-1, PWHT Requirements for P-No. 4
Lamination in Plates
VIII Div 1 - Marking of non-pressure parts
Subcontracted welding?
Use of separate WPS in combination
Laminations in plate materials
VIII DIV 1 - Code applicability for a vessel
Accreditation, ASME Codes - CD Rom vs Books?
Pin hole leaks not detected
Required # of specimens for production impact tests
WPS/PQR vs WPQ variables and Limits of Qualification
ASME Section VIII Div 1 - UW-12(d)
Stamping of "U" Parts ?, MTRs Section I and B31.1?
Material Test Reports Section I
ASTM vs ASME materials for Code use
SMAW Welder qualification with F-3 and F-4 Welder Performance Qualification Limits
Conditioning of electrodes
Acceptable Code Edition and Addenda
Certification of Data Reports and R Forms – sequence
Weld joint prep requirements
Socket Welded connections in boiler proper
Boiler field erection of piping
Submerged Arc Welding Questions:
Section IX Welder "t" thickness range multiple process
Material marking - VIII Div 1
Small Nozzle attachments - Section VIII Div1
Welding Qualification Ranges
Welding Questions
"Coded markings" (Material) - UG-77(a), PG-77.2
Section I double block valves & free blow drains
Pressure Relief Requirements - VIII Div 1
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VIII Div 1 - seamless head "Quality Factor - E" Seamless Head "Quality Factor", UW11(a)(b)
Welding Position Section IX, QW-461.9
VIII Div 1 - UW-13 head to shell alignment
QW-202.4 Combination Welding
Material Certification
Welder Continuity and Qualification
Section VIII Div 1 - "Low Temperature Vessel"
Calibration of pressure gauges
Tube hole deburring - Section IV
Calculated Test Pressure - VIII Div1
VIII Div 1 - Vacuum, RT- nameplate
SAW welding procedure Changes, PQR requirements for Corrosion Resistant Overlay
Inspection Openings - VIII Div 1
Root pass WPS - QW-200.4(b)
Use of SA 36 - VIII Div 1
Nozzle replacement - VIII Div 1
DA Tank - small nozzle welds
NCRs - Section I and VIII Div 1
WPS qualification with impacts
Section I - connection off water column, & B31.1 valve
PWHT - placement of thermocouples VIII Div 1
In process inspection by the AI? - VIII Div 1
WPS for Dissimilar Thickness Joint
RT designator Section VIII Div1?
Lifting Lug calculations VIII Div 1
VIII Div 1 - Opening Reinforcement Calculations
VIII Div 1 - production impact test?
Impact Test Exemptions for ERW Pipe
Section IX Welder Qualification using S numbers
VIII Div 1 - production impact test?
Impact Test Exemptions for ERW Pipe
Section IX Welder Qualification using S numbers
Internal Inspection
Application of UCS-68(c) to UG-20(f)
VIII-1 material marking and "piggy back welding"
Calculating the MDMT - VIII Div1
Material Test Reports - EDI (Electronic Data Interchange)
PWHT Question - ASME I
VIII Div 1 - UG-93 material marking
Boiler Parts and BEP
Section I - Use of SA-36 material
NDE Level III qualification
VIII Div 1 - UCS-66 - "GOVERNING" thickness for establishing MDMT?
Rods and Bars used as nozzles in VIII Div 1 vessels?
VIII Div 1 vessel hydrostatically tested in the vertical position
86. VIII Div 1 vessel Code boundary
87. VIII Div 1 UW-11(a)(5)(b)
88. Section I, PG-99, Application of Insulation Prior to Hydrostatic Test
89. VIII Div 1 purpose of final pressure test
90. VIII Div 1 impact test requirements for UG-11 manway assemblies.
91. B31 Socket Weld Fitting Fit-Up Gap
92. Where in the ASME Code are international materials listed?
93. VIII Div 1, UG-10 and identical ASTM material
94: VIII Div 1 - UW-16(c) - Nozzle attachment welds, full penetration?
95: Titanium not reported as an unspecified element as required by SA-20 par. 7.1.1.1
96: ASME Section I - difference between tube and pipe
97: UG-99 - Hydrostatic test pressure - VIII Div 1
98: Section I power boiler hydrostatic test water temperature
1. VIII Div 1: U-1(c)(2)(j) 3,000 psi Limit:
The 3,000 psi number is a conservative limit which is intended to alert the designer to the fact
that the design principles upon which the Code is based may not be satisfactory (from a
manufacturing or economic point of view) for the design of high pressure vessels. The design
rules of Section VIII, Division 1 are based on elastic behavior of thin shells in which failure is
assumed to occur when the yield point is reached. According to a survey that was made,
pressure vessels up to 10,000 psi can be constructed to Section VIII, Division 1 without suffering
a manufacturing or economic hardship. The service conditions of the vessel may require special
engineering considerations which the Code does not address. For example, for vessels intended
for very high pressure (>> 10,000 psi) it becomes necessary to base the design on plastic
analysis, and to prestress (autofrettage) the vessel to meet the service conditions.
These design deviations are necessary to satisfy the service conditions. It is recommended that
for a high pressure vessel the designer shall design for a particular service and after the service
conditions have been satisfied, the design can be reviewed for Code compliance. If the pressure
vessel construction meets all Code requirements the "U" stamp can be applied. However, when
deviations from Code rules are necessary to satisfy service conditions, and the vessel is to be
operated in a state with a pressure vessel law, then the owner/user and/or his designated agent
must petition the jurisdictional authority for a State Special Stamping.
In most cases for pressures under 5,000 psi, special design considerations would probably not be
necessary. As a minimum you should check that the thin shell equations of UG-27 are valid (See
UG-27(c)(1)), and check if fatigue loads need to be considered per UG-22.
To summarize, U-1(d) places no limit on the pressure for which a vessel may be designed and
stamped according to Section VIII, Division 1. The paragraph alerts designers that for pressures
greater than 3000 psi, design procedures unique to the design of high pressure equipment may be
needed to meet the service requirements of the vessel. However, the Code symbol stamp may
only be placed on the completed vessel if all of the requirements of the Code have been met.
--------------------------------------------------------------------------------------------
2. VIII-1, UG-99(g) No Leakage during Hydro Inspection
Question: The new A97 requires that there be no leakage during the time of the hydro
inspection. Does this applied to flanges on nozzles intended for flanged connections to piping?
Answer: The mention of leakage at temporary seals only applied to plugs etc. used on
nozzles intended for welded connections. Thus if the flange is included within the scope of the
vessel, and the shop uses a blind flange to close off the opening, this flanged joint cannot leak at
2/3 the test pressure.
-------------------------------------------------------------------------------------------3. - VIII Div 1, UHA -51 High Alloy steel impacts?
Question:
* The base material is 304L 0.77" in thickness.
* The desired MDMT is -320 F. ' Per UHA-51(d) the base material and HAZ are exempted from
impact tests based on thickness.
* Per UHA-51(e)(1) the weld metal is required to be impact tested, since MDMT < -150F.
* Per UHA-51(b) the WPS must be qualified with impacts.
* Per QW-451 the shop can prepare a coupon which is 1/16" thick and qualify for actual base
metal thickness of 0.077".
* Then Per UG-84(c)(3) impact tests would not be required since a Charpy specimen with a
width along the notch greater than or equal to 0.099" cannot be obtained. In my opinion this
would always take precedence over any other Code requirements that would require impact tests.
Production impact tests would not be required again per UG-84(c)(3). If the shop instead
qualifies their procedure with a coupon equal to or greater in thickness than 0.099", then they
would have to qualify the procedure with impacts. However production impact tests would still
not be required per UG-84(c)(3).
4. - P-3A Data Report
Question: There is no place on The P-3A Data Reports for an Engineering Contractor to
document Partial Data Reports such as is on the P-3. Can this be done by attaching a P-6 to the
P-3A?
Answer: No. PG-112.2.2 requires a P-3 Data Report to be used to record all items on a water
tube boiler. If an Engineering contractor is going to accept overall responsibility, then the P-3 is
checked as not being the Master. The P-3A then becomes the Master and the Engineering
Contractor will certify it to accept responsibility for the design certification. All boiler
components are certified on the appropriate Manufacturer's Data Reports. All Partial Data
Reports would be referenced on the P-3. (see PG-112.2.4), or P-6 attached to the P-3. If the
engineering contractor has fabricating facilities (see PG-104, Note 1), fabrication activities
would be documented on the appropriate Manufacturer's Data Report. The P-3A is used only to
certify design. Note: Because of the multiple use of the P-3, the P-3 used to document all boiler
components may also have attached (and referenced) P-3's.
--------------------------------------------------------------------------------------
5. - VIII-1, UG-44 and B16.9 and B16.11 Fittings
Question: What is the Code's true intentions for the rating of ASME B16.9 and B16.11 fittings.
UG-44 states, Pressure-temperature ratings shall be in accordance with the appropriate standard
except that the pressure-temperature ratings for ASME B16.9 and B16.11 fittings shall be
calculated as for straight seamless pipe in accordance with the rules of this Division including
the maximum allowable stress for the material. "From this statement and ASME Interpretation
VIII-1-83-217, one could logically conclude that the Code's intentions were to exclude ASME
B16.9 and B16.11 fittings from UG-45. Also, one could argue that UG-44 states that the fitting
shall be rated as a straight seamless pipe to all rules of the division which includes UG-45. Is it
the intention of the Code to exclude ASME B16.9 and B16.11 fittings from UG-45?
Answer:
There have been numerous Code interpretations on this subject. However, as you
discovered, VIII-1-83-217 essentially states that UG-45 does not apply to B16.11 couplings since
no nozzle neck applies. I have given that opinion in the past, and would extend it to B16.9
fittings as well. I published a short explanation of establishing a pressure/temperature rating for
a B16.11 fitting in one of my previous newsletters (I will be mailing the complete set to you
today). I've clipped in Word format this portion of the newsletter, plus the set of interpretations
dealing with the subject. So in conclusion, I believe that ASME B16.9 and B16.11 do not
require UG-45 consideration.
Question 1: I need to use ASME B16.11 fittings in a pressure vessel that I am constructing to
Section VIII, Division 1. How do I figure out the allowable pressure/temperature rating for the
fitting?
Answer: ASME B16.11 is listed as an acceptable reference standard in both Table U-3 and
paragraph UG-44 of Section VIII-1. Normally if you are purchasing B16.11 fittings from a
manufacturer's catalog per UG-11(a) of Section VIII, it will provide the pressure/temperature
rating for the fittings based on either B31 piping applications or Section VIII. If a manufacturers'
pressure/temperature rating is unavailable, you can use the following method to establish an
MAWP. Per UG-44, the pressure/temperature rating for a B16.11 fitting is calculated for
straight seamless pipe in accordance with rules of Section VIII including the maximum
allowable stress for the material. Let's look at an example. Assume that we need to use an NPS 1
B16.11 threaded coupling for a vessel designed for 400 psi and 800oF. We need to select a class
designation for the fitting, so as a first cut let's select a Class 3000 fitting. Per 5.1 the material for
the fitting shall consist of forgings, bars, seamless pipe, or tubular products listed in Table 1 of
ASME/ANSI B16.34. From Table 1 select a carbon forging SA-105. Per B16.11 2.1.1 and Table
2, the pipe schedule corresponding to a Class 3000 fitting is Sch 160. The nominal wall thickness
for NPS 1 Sch 160 from B36.10 is 0.25 in. The allowable stress for SA-105 at 800oF is 12.0 ksi.
Using the minimum thickness of the Sch 160 pipe by accounting for the manufacturer's
undertolerance ( tmin = 0.875 x 0.25 = 0.219 in), the calculated ressure is:
P = SEt/Ro + 0.6t = 12000(1)(.219)/.658 +0.56(0.219) = 3,329 psi
Question: Is impact testing required for the welds in SA-53 Type E ERW pipe under the
following conditions?
(a) When the thickness at the weld exceeds « in. for all minimum design metal temperatures?
(b) When the thickness at the weld exceeds 5/16 in. and the minimum design metal temperature
is lower than 50oF?
Reply: Yes to (a) and (b).
However, the only time one would apply UCS-67(b) to ERW pipe, is if the pipe were fabricated
in the Code Manufacturer's shop. Otherwise, ERW pipe is treated as material and the weld is
ignored.
------------------------------------------------------------------------------------------6. - Power Boiler field hydro
Determination of Hydrostatic test pressure
Detail: Inquirer is getting conflicting information on how to determine the correct test pressure
for a field erected boiler. It seems the designer is stating the correct test pressure for the boiler,
and the erector does not think it is correct. The erector is wanting to consider the pressure ratings
for the piping support systems to determine the test pressure. It appears that the problem is they
want to test everything at once at one pressure, but do not know what MAWP to use as the basis
for calculating the test pressure. A simultaneous test is permissible per the requirements of
paragraph 137.3.1 of B31.1 for boiler external piping only. When a simultaneous test of the
boiler and the boiler external piping is conducted, test pressure shall be based on the MAWP of
the boiler proper as required by PG-99.1. Applying the requirements of PG-99.3 is inappropriate
for a drum type boiler. These requirements only apply to forced flow steam generators which
different pressure ratings within the boiler proper. Separate tests are to be conducted for
nonboiler external piping per paragraph 137.3.2; for each of the boiler support piping systems at
their required test pressures per paragraph 137.4 of B31.1. This will require some disassembly
and isolation blanking to preclude over pressurizing limiting components, if not performed as a
bench hydro at the fabrication point. If the piping systems are disassembled, when reassembled
they should be retested at the normal operating pressure for a final mechanical joint integrity
verification.
----------------------------------------------------------------------------------------7. Section IV Test Pressure requirements
Detail: Paragraphs HG-510(a) and (b) tend to be confusing when taken together. How do these
limits work together?
Response: It is the intent of Section IV that all boilers built to their Section be tested at a pressure
of at least 60 PSI, but not greater than 1.5 times Design pressure. For example, a 15 psi steam
boiler is tested at 60 psi which is the greater of 60 psi vs 1.5 times MAWP (37.5 psi). The
greatest pressure it may be tested at is 1.5 times design or 60 psi, whichever is greater. If this
boiler is designed for an MAWP of 15 psi steam, but the design is based on a design rating of 50
psi, it could be potentially be tested at 75 psi maximum vice 60 psi. This would give you an
acceptable test pressure range of 60-75 psi; with the lower limit based on MAWP, and the upper
limit based on Design pressure. Keep in mind that design pressure and MAWP do not have to be
the same number. The maximum overpressure is limited to 10 psi over the maximum limit, so if
the test pressure of 60 psi is selected, then the maximum pressure should be 70 psi, but could
theoretically be allowed to reach 85 psi applying these guidelines.
---------------------------------------------------------------------------------8. - Changing bolts after hydrotest - UG-99(g)
Question: Is it acceptable to change the bolts on the vessel after final hydro? The vessel is 100'
long and is comprised of 15' shell sections that are bolted together. The hydro is performed on
the entire vessel using SA-193 B7 bolts then dismantled for shipping. The vessel is then
reassembled on-site using different bolts (SA-193 B7 - Teflon coated). The AI had told the shop
that if they are ultimately going to use Teflon coated bolts then they have to use Teflon coated
bolts at the hydro.
Answer: Regarding the vessel that is being hydrostatically tested, dismantled and reassembled
using different bolts. These are mechanical joints and therefore the Code does not specifically
address the use of different bolting materials during hydro and final assembly. Therefore it
would be acceptable to use SA-193 B7 bolts for the hydrostatic test at the shop and SA-193 B7
Teflon coated bolts for the final assembly.
---------------------------------------------------------------------------------------9. - Section I, PG-109.3 - PP Stamping Scope
Question: Under PG-109.3 the PP stamp holder can fabricate boiler parts, such as headers or
other parts, involving only welding as covered by PW-41. PW-41 are requirements only for
welding of circumferential joints in pipes, tubes and headers. Can PP stamp holder fabricate
headers, involving also nozzles to header shell welding which is not covered by PW-41?
Response: The intent of this requirement is that components within the scope of the PW-41
limitations may be fabricated by PP stamp holders. This change was made fairly recently (97
Addenda if I remember correctly), to recognize that since we already allow PP holders to
assemble piping within the limits of BEP by welding, and since the components referenced in
PW-41 are within the limits of BEP but outside the boiler proper, it only makes sense to allow
the PP holder to fabricate those items as well. The statement within PG-109.3 was intended to
prohibit the use of a PP stamp to assemble drums and shells, or other major pressure components
of boilers, while allowing PP holders to fabricate smaller piping related components. This
change was part of the general movement to shift technical requirements for those things which
are outside the boiler proper to the Power Piping Code, B31.1.
------------------------------------------------------------------------------------------10. : VIII-1, PWHT Requirements for P-No. 4
Question: Client is welding an 8" thick tubesheet made from SA-182 F12 Cl2 material (P-No. 4
Gr. 1) to a 1 3/8" shell made from P-No. 1 material. Is PWHT required?
Answer: UCS-56(c) addresses the PWHT requirements for welded joints involving different PNumber groups. It states that the more restrictive PWHT requirement shall apply to the joint.
The P-No.1 material is exempt from PWHT, however the P-No. 4 will require PWHT, since
there are no applicable exemptions for your application. Per UW-40(f)(5)(c) the governing
nominal thickness for determining the holding time will be the thickness of the shell.
--------------------------------------------------------------------------
11. Lamination in Plates
Question: Is lamination in general a cause for rejection of a plate?
Background: The specific application is a bolted cover with a coupling in the center attached
with a single external fillet weld as a penetration. When pressurized with air, it bubbles through
the lamination and out the periphery of the plate.
Question: Is this acceptable?
Response: Obviously the leakage is unacceptable, but the lamination is not a problem. Since the
full thickness of the plate is present to resist the load due to pressure, the lamination is not of
itself a cause for rejection. To stop the leakage, back weld the coupling penetration to seal the
lamination from having a leak path. A minimum fillet weld to act as a seal weld is sufficient.
Laminations are not desirable where plates are joined to form a corner joint, because of the
potential for the load to be borne by a section thickness that is less than the nominal plate
thickness. This is why VIII Div 1, UG-93 requires that edge preps for corner joints be examined
by PT or MT to check for laminations. Another potential problem area is when the plate is a heat
transfer surface, and such a lamination may develop into a blister or bulge and affect
performance of the part, as well as allowing localized overheating of the metal to the point of
failure. In a pure pressure loading application such as a shell or head, the full section thickness is
carrying the load, so the lamination is not detrimental.
--------------------------------------------------------------------------------------------12. - VIII Div 1 - Marking of non-pressure parts
Question: What are the marking requirements for non-pressure parts welded to pressure vessels
in Section VIII Div 1?
Answer: Marking requirements for non-pressure parts UG-4(b) requires that non-pressure parts
attached to pressure retaining parts be of "weldable quality". UW-5(b) gives requirements for
proving "weldable quality", which means that a WPS has been qualified with this material.
Material identification requirements for non-pressure parts welded to pressure retaining parts are
found in UW-5(b)(1) and (2). Both reference the requirements of UG-10, UG-11, UG-15, and
UG-93. UG-10 requires identification per the specification. UG-11 permits reduced markings for
pressure parts. UG-15 provides recertification and redesignation of a material in the same fashion
as UG-10, with markings per specification. UG-93 requires all product forms other than plate to
be marked with the specification , grade, type, and class; trace ability to a specific heat and lot is
not required. When the Manufacturer begins subdividing the material, UG-94 allows the use of a
coded marking, referencing UG-77. UG-77 requires control of transferred markings to be
addressed in the quality control system. Additionally, UG-93(a)(3)(b) makes a similar statement.
Consequently, if the required markings are used, no QC Manual description of the system is
required.
If a coded marking system is used, it's description is required in the QC Manual. This is
consistent with the issued interpretations on this subject.
---------------------------------------------------------------------------------
13. - Subcontracted welding?
Question: Is it possible to subcontract welding and other fabrication operations to other
organizations?
Answer: There are two scenarios. One involves one Certificate Holder subcontracting
fabrication to another Certificate Holder, having the subcontractor report the work performed on
a U-2 form (Partial Data Report), and then incorporating this component into a completed vessel
with stamping and certification by the original Certificate Holder. The responsibility for design
may be assumed by either party. Responsibility for component fabrication is assumed by the
subcontractor. The subcontractor would have his own Code certificate, his own welding
procedures and welder qualifications, his own inspection and certification. The work performed
by him would be reported to the final Manufacturer, who accepts responsibility for it when
incorporating the component into the final vessel. This type of approach works well with either a
full time or a part time fabrication operation. It is a good way to outsource some work due to cost
considerations, manage cyclic production demands, or compensate for equipment limitations.
The second scenario involves what is referred to as a "welding by others" program. This requires
a modification of the Certificate Holder's QC Program to incorporate the requirements of UW26(d). This provides details of how such a program is implemented and controlled, and includes
the designation of individuals responsible for the various actions and oversight required. In this
situation, the Certificate Holder (using his own welding procedures) conducts welder
qualification testing of the subcontractors welders. He then employs the subcontractors welders
to weld products of his design, using his welding procedures, under his direct control and
supervision. This is usually accomplished by assigning a specific individual to the
subcontractors shop to oversee operations. The Authorized Inspector is involved in the
implementation of this program to the extent he feels necessary. Usually the Inspector will rotate
between the Certificate holder's facility and the subcontractor's facility. I have only seen this
applied to a full time inspection location. It would be difficult to coordinate with a part time
location. This offers some advantages for cost reduction and cyclic production demands as well.
-------------------------------------------------------------------------------14. Use of separate WPS in combination
Detail: Inquirer called to ask if it is possible to apply two separately qualified WPS to the same
joint in combination without qualification of a combined PQR.
Response: Per QW-200.4, it is acceptable to apply both WPS to the same joint without further
qualification. The deposited weld metal qualification ranges may be "stacked", allowing the
application of the maximum qualified thickness of deposited weld metal for each WPS/process
in a single joint. However, the user is cautioned that the maximum base metal thickness qualified
for the most limiting WPS must be applied. The base metal thickness ranges cannot be "stacked"
to qualify for a greater thickness in combination.
-------------------------------------------------------------------------------15. - Laminations in plate materials
Question: What is the acceptability of laminations in plate materials in pressure vessels.
Answer: Since the full thickness of the plate is present to resist the load due to pressure, the
lamination is not a cause for rejection. Laminations are not desirable where plates are joined to
form a corner joint, because of the potential for the load to peel the laminations and reduce the
strength of the material section. This is why UG-93(d) of Section VIII, Division 1 requires that
edge preps for corner joints be examined by PT or MT to check for laminations. Another
potential problem area is when the plate is a heat transfer surface, and such a lamination may
develop into a blister or bulge and affect heat transfer performance of the part, as well as
allowing localized overheating of the metal to the point of failure. In a pure pressure loading
application such as a shell or head, the full section thickness is carrying the load, so the
lamination is acceptable and not detrimental. Some specific customers may have objections to
laminations in shell or head plates. But, this is a matter of agreement between the client and the
Manufacturer. The ASME Code has no prohibitions against plate laminations other than as
described above for corner joints.
-------------------------------------------------------------------------------16. - VIII DIV 1 - Code applicability for a vessel
Question: About Code applicability for a specific vessel design. It is a shell and tube heat
exchanger used as a waste heat recovery heater, using flue gases to heat water. The intended
application is for 15 psi or less on the water side, the gas side is vented to atmosphere as the
gasses escape.
Response: The heat exchanger design presented may be considered outside the scope of the
ASME Code, Section VIII, Division 1 for Unfired Pressure Vessels by the following reasoning:
(a). Paragraph U-1(c)(2)(h) excludes vessels of unlimited size from the scope of the Code when
rated for internal or external pressures of less than 15 psi.
(b). Paragraph U-1(c)(2)(f) excludes vessels containing only water under pressure, provided the
pressure does not exceed 300 psi and the temperature does not exceed 210F. Code
Interpretations have been issued which confer applicability of this paragraph to heat exchanger
applications.
(c). Paragraph U-1(c)(2)(g) excludes hot water storage tanks heated by steam
or other indirect means when the heat input is limited to 200, 000 BTU/hr, temperature is limited
to 210F, and volume is 120 gals or less. While it is difficult to conclusively determine that these
parameters are not exceeded with the information provided, it appears that they are not.
Paragraph U-1(c)(2) permits the application of the Code symbol to objects which are normally
outside the Scope of the Code when constructed to meet all the applicable requirements. So,
even if the object is determined to be outside the scope, it may be built to meet the Code and
stamped as being in compliance with it.
-------------------------------------------------------------------------------17. Accreditation, ASME Codes - CD Rom vs Books?
Company called to ask if it is required to have hard copies of the ASME Code available for the
ASME joint review. They currently have them on CD ROM, and was told they needed hard
copies as well.
Response: Yes, hardcopies are required. It is not clearly indicated in the ASME application
package sent to applicants, because it says in the cover letter that the applicant must have a
"published copy" of the Code. The ASME considers the definition of a published copy to be a
hard copy as purchased from ASME. Not a photocopy or CD ROM. Since the ASME only has
direct control of what is published in the hard copies, it does not recognize any other form. The
CD ROM version is produced under license, and not by ASME, so they cannot be certain of
content.
-------------------------------------------------------------------------------18. - Pin hole leaks not detected
A manufacturer of ASME pressure vessels and a distributor of vessels that are made by others
has a situation with their major supplier. They make a 20" diameter horizontal air receiver for
us. A particular end user has consistently returned vessels for pin hole leaks. These vessels have
been made in different production runs over the past year. This end user tests with n itrogen gas
at 75 psi. The fabricator hydrotests at 300 psi.
Question: Is it conceivable that these leaks that are detectable by the end user, could go
unnoticed during the fabricators' hydrotest? The most recent leaking vessel was returned to the
fabricator with the leaks marked, and the fabricator said that it took 1.5 and 3 hours to detect the
two leaks.
Response: It is definitely possible. Think of it this way, which molecule is larger, N2 or H2O?
Depending on the aspect the molecule presents, the N2 is definitely more likely to slip out of a
tight opening, especially if it is monataomic Nitrogen. Pneumatic testing or other tests using a
gas instead of a fluid more readily leak when a pin hole exists for this reason. It has always been
harder to detect very small leaks with hydrostatic tests. If the vessel will see gaseous service, or
this type of leak test is a potential acceptance criteria, then I suggest that the vessel be
pneumatically tested; either in addition to, or in place of, the hydrostatic test. Even at that, the
leaks may be small enough that they could be missed if the tester is not thoroughly inspecting the
vessel. This type of tight pinhole is characteristic of Subarc welds made with a heavily recycled
flux. After breaking down in the heat of the welding process, the flux fragments into a fine
powder, called "flux flour". This "flux flour" more readily absorbs moisture and clings to dirt,
oil, grease. grinding debris, and other contaminants which cause the formation of very fine
pinhole porosity. Fabricators which are aggressively recycling flux are suggested to dump the
batch about once a month, or sift out the "flux flour" with a screen.
-------------------------------------------------------------------------------19. - Required # of specimens for production impact tests
Question: "For production impact test plates of a Section VIII Div 1 vessel which the base metal
is over 1.5 inch in thickness, how many sets of test specimens be tested?" Specifically UG84(i)(1), which tells the user to perform production impact tests per UG-84(g). Are three sets of
specimens were required [2 in the weld deposit, 1 in the HAZ; per UG-84(h)(3)] due to the
material thickness, or only two sets of specimens were required [1 in the weld deposit, and 1 in
the HAZ; per UG-84(g)] for production impact tests?
Answer: The three sets of specimens in the question refer to are impact tests of Welding
Procedure Qualifications on base metal thick nesses greater than 1-1/2 inches, as set forth in UG84(h)(3). This requires the weld to be tested in the weld metal within 1/16 in.of the surface, in
the weld metal near the center, and in the HAZ of the base metal. This requirement exists for
Welding Procedure Qualification Tests only. The regular weld impact test requirements of UG84(g) only mandate two sets of specimens; one of the weld metal within 1/16 in. of the surface,
and the HAZ of the base metal. Production impact tests are mandated as a check of the
fabricating process to ensure the qualified properties are being obtained in the production
component. The tests are invoked when extremes of service onditions warrant additional
verification. Since the production impact test is only a verification of previously qualified
properties during fabrication, it is not intended to invoke the full qualification test regimen, but
merely a check regimen. Production testing only requires two sets of specimens to be taken from
the locations called for in UG-84(g).
-------------------------------------------------------------------------------20. - WPS/PQR vs WPQ variables and Limits of Qualification
Detail: I am confused about the Welding Performance Qualification. For instance, a welder used
SA53 pipe test material which is P1 material, I want to know what kind of material he will be
qualified for? Is he qualified to weld production material SA-240-304(P8) by using SA53 as
testing coupon? I know there is a paragraph regarding welding qualification in QW-423.1. On
the other hand, the base material in the WPS is a essential variable.
Response: This is a very common problem. It is very easy to confuse procedure and
performance requirements and try to apply them inappropriately. The welder you described who
qualifies on a SA-53 pipe coupon becomes qualified for that base metal and the following
additional weld metals: P-No.1 thru P-No. 11, P-No. 34, and P-No. 4X (where X is a
placeholder, indicating the 40 series P-Nos. which are nickel alloys). This sounds great, huh?
However, there are some traps here. The welder must use the same process, with the same
essential variables as qualified, such as the F-No., position, thickness limits, etc.; unless he has
other WPQs that support the extension of the limits of qualification for the essential variables.
The actual essential variables change with the process, as shown in QW-416 and QW-350. At
the same time, the welder may be qualified to weld the other base metals, but unless he has a
WPS that has been qualified for those base metals (and all processes have base metal as an
essential variable) he cannot weld it in compliance with Code requirements. There are one or
two minor exceptions found in QW-424, but this is generally true. One example that I have seen
is where the welder welded stainless with a WPS qualified for carbon steel. When I pointed this
out, the client stated that the process was covered by QW-423, since the welder is qualified for
the various base metals as stated above. Sure the welder is qualified, I said, but the process was
not qualified for these base metals so the weld is not acceptable. Once he realized that I was
right, we looked through his extensive book of WPSs and found one that was identical to the
carbon steel WPS, but was qualified for stainless. Everything else was identical except the base
metal. I have also seen people try to use the welder's qualified deposited weld metal thickness
range to try to weld using a procedure that was qualified for lesser thickness' than the production
base metal using the same reasoning as above. Remember that Code welding is a two by two
matrix. Across the top are: "Welder Not Qualified" and "Welder Qualified". Down the left hand
side are: "Procedure Not Qualified" and "Procedure Qualified". Unless you are in the box where
the coordinates "Procedure Qualified" and "Welder Qualified" intersect, it's not a Code
compliant weld. Procedure qualification and Welder qualification are achieved and verified
independently, unless the welder in question was the welder who made the test coupons for the
PQR. Then the test is documented on separate PQR and WPQ forms using the same data.
-------------------------------------------------------------------------------21. - ASME Section VIII Div 1 - UW-12(d)
Question: UW-12(d) requires a spot radiograph [per UW-11(a)(5)(b)] be taken on each 50 feet
of circumferential seams attaching elliptical or torispherical heads to a seamless shell to apply a
joint efficiency of 1.0 in the calculation of the shell or head thickness, even if they are seamless.
If this RT requirement is not applied, 85% is the highest permitted joint efficiency. In the
application to ERW pipe shells, it appears to be a "double penalty"; since ERW stress values
already have an 85% efficiency applied to them, and this requirement reduces the efficiency even
further.
Response: This requirement is the result of a compromise worked out when Section VIII revised
it's design philosophy to become a "design by joint" Code. It became apparent that designing a
vessel with a seamless shell and seamless dished heads would rate the same joint efficiency in
shell and head thickness calculations as a totally seamless vessel, since the circumferential seams
need only be half as strong as the seamless shell. The fact that a welded vessel could be designed
for the same thickness as a seamless one was a distasteful possibility for the Code committee, so
this provision was put in place to gain acceptance for the Code revision.
If a seamless hemispherical head is attached to the shell, the head is calculated with an efficiency
determined from Table UW-12. The shell is calculated under the provisions of UW-12(d).
However, if a flat head (tube sheet, or flange also) is attached at both ends of a shell, you may
ignore the radiography requirements of UW-12(d) and apply the appropriate joint efficiency for
the shell (based upon joint type and degree of examination) from Table UW-12 to the shell
thickness calculation. This is permitted because of the difficulty in shooting and properly
interpreting a radiograph for a corner joint (or fillet welds attaching flanges). The Code
committees decided that in this scenario, the rules of UW-12(d) would be waived. If there is a
flat head at one end and a dished head at the other end, the rules of UW-12(d) still apply to the
shell and dished head calculations.
-------------------------------------------------------------------------------22. - Stamping of "U" Parts ?, MTRs Section I and B31.1?
Question: What is the the proper stamping of "parts", and does the Code require such things as
RT2, W, or the other things addressed in UG-116(a) through (f).
Response: The only required information to be stamped or included in the nameplate of a "Part"
under Section VIII, Division 1 rules is as set forth in UG-116(h). The information in UG-116(a)
thru (f) is for stamping or nameplates of the completed vessel. Information concerning any of the
aspects addressed by these markings (PWHT, RT, etc) is addressed on the U-2 or U-2A, and not
the stamping. The Manufacturer of the final vessel is obligated to address these areas on the final
U-1 or U-1A and stamping or nameplate upon final certification of the completed vessel.
23. Material Test Reports Section I
Question: What are the MTR requirements are for piping when fabricated under Section I and
B31.1.
Response: The following references and requirements apply:
(a). B31.1 explicitly requires MTRs for materials used in pressure retaining service in paragraph
123.2.2(A).(power piping)
(b). Section I makes no direct explicit requirement for MTRs in the main text of the book, but
alludes to it in the Appendix, in paragraph A-302.4. It is widely understood that MTRs are
required for Section I construction (boiler proper piping).
-------------------------------------------------------------------------------24. - ASTM vs ASME materials for Code use
Question: Under what conditions, may ASTM Specification materials be used for ASME
pressure items?
Answer: The following would apply:
(1). If the ASTM Material has an identical corresponding ASME Specification with the same
number (i.e.: A-106B corresponds to SA-106B); and the date code For the ASTM Material is one
of the acceptable dates listed in Appendix A of Section II, Part A; and the corresponding ASME
Specification is acceptable for the construction Code which applies. If this is the case, the
material can be accepted as is, and used as ASME Specification material. No recertification or
remarking is necessary.
(2). If the ASTM Material does not have an identical corresponding ASME Specification with
the same number (i.e.: A-106B corresponds to SA-106B), it may be compared to a known ASME
Specification acceptable for the construction Code which applies. If comparison of the chemical
composition and mechanical properties show the material to meet the requirements for the
ASME Specification, it may be accepted for use as the ASME Specification material. The
procedure for recertification and remarking of the material is found in the construction Code. For
example for Section VIII, Division 1, it is found in UG-10. Slip-on-flanges - limitations B31.1
and I. The boiler external piping limitations are "except slip-on flanges shall be limited in
application to no higher than Class 300 primary service rating" - B31.1 par. 104.5.1 . Also
boiler proper Section I par. PG-42.4.7 states "slip=on flanges shall not exceed NPS 4".
-------------------------------------------------------------------------------25. - SMAW Welder qualification with F-3 and F-4 Welder Performance Qualification Limits
Detail: Inquirer called to ask for assistance in verifying the limits of qualification applicable to a
given WPQ scenario. The welder deposited a 1/8 " weld root pass using SMAW with an F-3
Electrode without backing. He then filled the rest of the 0.412" thick coupon using SMAW with
an F-4 Electrode, now with the root pass as a backing. Since F-4 or F-3 electrodes qualify the
welder to apply all lower F-Nos. with backing, how should the limits of qualification be listed on
the WPQ?
Response: Weld Deposit Thickness- Range Qualified is: F-1 thru F-4 qualified for 0.824"
deposited weld metal with backing, F-3 qualified for 0.25" without backing. Reference: ASME
Section IX - QW-353, 404.15, 433, 306
-------------------------------------------------------------------------------26. - Conditioning of electrodes
Question: What about the proper conditioning of coated SMAW electrodes. The specific
electrodes in question are E-7018.
Response: ASME Section II C, Table A-1 in the Annex for SFA-5.5 gives specific guidance for
the conditioning of SMAW electrodes. The text of A6.11 has some information of significance
as well. In general, low hydrogen electrodes have to be kept in a controlled and usually heated
environment. Other electrodes may be kept at ambient temperature. In fact, it states in A6.11.4
that some electrodes may be damaged if kept in heated storage, as it will dry them out too much,
and they do not function as intended without some amount of moisture in the coatings. If the
manufacturer does not provide recommendations for conditioning, follow the guidelines of Table
A-1. Many manufacturers of low hydrogen electrodes have simply recommended storage at 50F
above ambient to preclude absorption of moisture.
-------------------------------------------------------------------------------27. - Acceptable Code Edition and Addenda
Question: Is it possible to for a Manufacturer to accept a contract to fabricate a pressure vessel to
a previous Edition and Addenda of the Code. If not, where is this prohibited?
Response: In the Forward of of Section VIII, Division 1 the Code it states: "After Code
revisions are approved by Council they may be used beginning with the date of issuance shown
on the Addenda. Revisions become mandatory as minimum requirements six months after such
date of issuance, except for boilers or pressure vessels contracted for prior to the end of the sixmonth period." This means that the vessel may only be contracted for the Code Edition and
Addenda in effect at the time of the contract. During this six month "window" of voluntary
implementation of the Addenda, either Addenda (or Edition) may be applied as a matter of
agreement between the Manufacturer and the customer. Once the vessel is contracted for, that
Edition and Addenda may be followed until the vessel is completed, even if the construction
covers a prolonged period.
28. Welder limits
Question: Welder qualification thickness limits are based on both the deposit weld metal and the
F number. If a welder qualifies using both F3 and F4, the qualified deposited weld metal
thickness for F4 will only be twice the actual deposited thickness of the F4 weld metal. F3
would be the combined F3 & F4. is this correct?
Response: Don't forget the important role that backing plays in this application. QW-433 spells
this out very clearly. Since F-4 also qualifies F-3 and the lower F Numbers with backing, the
qualified thickness range for depositing weld metal with backing using the F-3 and lower F
Number electrodes is equal to twice the total deposited weld metal thickness (F-3 and F-4
combined). If depositing weld metal without backing, the qualified thickness range for deposited
weld metal would only be twice the actual deposited thickness for each F Number, and then only
if each was deposited without backing during the qualification test. Chances are only one F
Number was deposited without backing, and the other F Number was deposited over the top of it
(essentially with backing).
Follow-up to the above question:
QW-306 clearly identifies that the thickness qualification parameters are a function of all other
variables. This does not simply effect F# and thickness. The words encompass thickness
qualification being dependant upon ANY essential variable.
Question: If a welder is qualified on a 3" sch 5 (.083) coupon in the 6G and qualified on a 1" sch
80 (.179t) pipe coupon in the 1G, all other variables being the same, he is only qualified to weld
on a 2" pipe up to .166t in any position. After attaining that thickness he must change to 1G. If
the 3" coupon was F4 with backing and the 1" coupon was F3 without backing, then the welder
is not qualified on 2" pipe with F4 over .166t even in the 1G.
response: If the 3" coupon was F4 with backing and the 1" coupon was F3 without backing,
then the welder is not qualified on 2" pipe with F4 over 166t even in the 1G. The F-4
qualification is no good for welding the 2" pipe at all if it is intended to be welded without
backing. F-4 may be used to deposit 0.166" of weld metal only if welding with backing.
-------------------------------------------------------------------------------28. - Certification of Data Reports and R Forms – sequence
It has been brought to our attention that some Inspectors have been signing Data Reports and R
Forms prior to the Manufacturer's representative. In order to clarify HSB and ASME/NB
requirements please review the following:
The HSB Engineering Services Manual paragraph 4552.9(a) states "All Data Reports (and R
Forms per par (b)) shall be properly completed and certified by the manufacturer prior to being
signed by the Inspector".
ASME Section VIII Div 1 requires the Manufacturer to "prepare the Manufacturer's Data Report
and have it certified by the Inspector". UG-90(b)(18). Paragraph UG-90(c)(1)(n) discusses the
Inspector signing the Data Report when the "vessel, to the best of his knowledge and belief, is in
compliance with all provisions of the Code". This includes the certification signature of the
Manufacturer's representative.
The NBIC paragraph RA-2151(p) discusses the responsibility of the Manufacture for preparing,
signing, and presenting the R Form to the Inspector. Paragraphs RC-2071(b) and 3051 goes on
to state "the Inspector shall indicate acceptance by signing the R Form".
-------------------------------------------------------------------------------29. - Wed joint prep requirements
Question: How about minimum requirements for weld joint preparation, and where a hole is
flame cut into a shell, and a coupling is welded to the shell with a single fillet weld from the
outside only? No preparation is made to the flame cut edge prior to welding.
Answer: UW-31(a) states "When plates are shaped by oxygen or arc cutting, the edges to be
welded shall be uniform and smooth and freed of all loose scale and slag accumulation before
welding.(See UG-76 and UCS-5)". UG-76(a) states "After oxygen or arc cutting, all slag or
detrimental discoloration of material which has been molten shall be removed by mechanical
means prior to further fabrication or use." UCS-5 prohibits flame cutting and welded
construction using materials with a carbon content greater than 0.35%
Section I PW-29.1 states "The preparation of joints prior to welding may involve any of the
conventional methods in use such as machining, thermal cutting, chipping, grinding, or
combinations of these."
PW-29.2 states "Where thermal cutting is used, the effect on the mechanical and metallurgical
properties of the base metal shall be taken into consideration."
PW-29.3 states "The method of base metal preparation used shall leave the welding groove with
reasonably smooth surfaces and free from deep notches, striations, or irregularities. The surfaces
for welding shall be free of all scale, rust, oil, grease, or other foreign materials."
Section IV
HW-801(a), (b), and (c) are identical to PW-29.1, .2, and .3 respectively. Edges left behind by
plasma cutting machines are the only arc cuts that might be acceptable for further welding
without preparation. These edges are almost always uniform in thickness, smooth edged, and
contain virtually no slag. The heat input is so highly localized that virtually no detrimental
effects on the properties of the remaining base materials are observed. Edges cut by flame or
oxygen cutting generally have slag, and irregular edge, and often an irregular thickness. This is
not conducive to ensuring adequate penetration and fusion throughout the full thickness of the
joint without inclusions. A Manufacturer wanting to flame cut a hole into a shell, and attach a
coupling to the shell with a single fillet weld from the outside only with no joint preparation
prior to welding, should be required to demonstrate that he is able to complete an acceptable
quality weld under such conditions. Satisfactory completion of such a demonstration, with
appropriate testing of the finished weld joint, satisfies the Manufacturer's burden of proof to the
Inspector the he has achieved compliance with the requirements of the Code paragraphs cited
above without joint preparation. HW-810(c) requires that tack welds "be removed completely
when they have served their purpose, or their stopping and starting ends shall be properly
prepared by grinding or other suitable means so that they may be satisfactorily incorporated in
the final weld." Are these requirements satisfied when the tack weld is made in such a manner
that the starting and stopping ends are blended into the base metal and therefore suitable for
incorporation into the final weld without modification, or when the tack welds are completely remelted and consumed into the root of the weld?
Reply: Yes, with concurrence of the Authorized Inspector.
-------------------------------------------------------------------------------30. - Socket Welded connections in boiler proper
Question: What about the acceptability for a socket welded joint within the boiler setting. The
intention is to weld a NPS 4 socket welded fitting into the shell with double full fillet welds, and
then socket weld piping to the fitting for attachment of the safety relief valve. Is this an
acceptable arrangement?
Answer: Use of a socket welded fitting within the boiler setting is acceptable under PG-42,
provided it complies with ASME B16.11. Attachment of the fitting to the boiler shell with
double full fillet welds is permitted per Figure PW-16.1, Sketch (d). Socket welded joints of this
size within the boiler setting are not permitted per PW-41.5.1, however this particular joint is not
within the boiler setting. This joint is the point of termination of the Scope of the Section I
technical jurisdiction as shown in Figure PG-58.3.1. This weld joint and the attached piping
come under ASME B31.1 Power Piping. Socket welded fittings are permitted in this size for this
service, but socket welded flanges are restricted in size.
-------------------------------------------------------------------------------31. - Boiler field erection of piping
Question: What is the required documentation for valves, flanges, and other components of
piping being welded together in a boiler field erection. The components themselves do not
require documentation as they are acceptable as standard pressure parts under PG-11, and meet
the referenced specifications under PG-42, including markings. The issue is whether or not the
components need to be included on a P-4A, P-4B, P-6 or other documentation for the piping.
Answer: In researching this issue, the following ASME interpretation applies:
Question: May an Authorized Inspector accept valves, fittings, and flanges meeting the
requirements of PG-42 without such valves, fittings, and flanges being identified on a
Manufacturer's Data Report?
Reply (4): Yes.
The interpretation addresses this issue quite nicely. In addition, the guides for preparing the P-4A
and P-4B data reports tell the reader only to document the piping itself, and not the components.
We have to assume that the reason for this is because the valves, flanges and other components
are adequately marked to identify them as being in compliance with the Code without further
documentation. This is not true of the piping, as the material markings will often be covered by
paint, or otherwise lost. In conclusion we believe that it is appropriate to accept the valves and
other non-pipe components based upon their own markings, and that they do not need to be
included on the P-4A, P-4B, or P-6 forms used to document piping assemblies.
--------------------------------------------------------------------------------
32. Submerged Arc Welding Questions:
Question(1): What requirements exist regarding the recycling of subarc flux that was not
incorporated into the weld or the slag layer?
Question (2): Why is there a supplementary essential variable for procedure qualification when
changing from multiple pass welds to single pass welds in SAW?
Response: 1. No specific requirements exist for recycling unincorporated flux for reuse in
Section IX or the Construction Codes. This is a widely accepted practice, because failure to
recycle the flux can result in very high production costs. Some important things to keep in mind
when recycling the flux:
(a). Flux contamination with grease, oil, dirt, grinding dust, and excessive moisture absorption
are all problems for subarc welds. These are all known to cause excessive porosity, often very
characteristic for the specific type of contamination involved. Keeping excess flux in closed and
airtight containers to control such contamination is a good start. Minimizing grinding in the
vicinity of the welding is another. Keeping the area clean is another. Having a mechanism that
"catches" the flux instead of letting it fall into uncontrolled areas is also good. Finally, be careful
not to allow slag fragments to fall into the flux system.
(b). Flux breaks down after repeated exposure to welding heat to a very fine dust referred to as
"flux flour". This dust has a very high affinity for absorption of moisture, and consequently can
affect weld quality. Occasionally dumping the recycling system or mechanically separating the
dust from the flux is the best way to control this effect.
( c). Some shops use recrushed slag as flux because it is cheaper. This is acceptable, provided
that the welding procedure has been qualified for this electrode-flux combination. Special testing
requirements need to be met for recrushed slag fluxes prior to their use.
Response (2): When welding a joint with the subarc process, a significant heat affected zone is
created. In a single pass the effect is very pronounced. In a multiple pass procedure, the
subsequent passes serve to partial stress relieve the previous passes heat affected zones (HAZ).
Since the greatest area of vulnerability for brittle fracture is the HAZ of a weld, this is why
changing from multiple passes to single passes is an essential variable for impact tested
applications. A significant difference in the fracture toughness properties results from the
change, which obviously affects the impact properties of the HAZ.
-------------------------------------------------------------------------------33. - Section IX Welder "t" thickness range multiple process
Question: regarding the application of QW-452.1 performance qualification ranges for the
following WPQ conditions: Pipe Coupon with 0.864" wall thickness, Welded with 0.187
GTAW root, and 0.670 SMAW fill.
Response: (Note: 0.187 + 0.670 = 0.857") Applying QW-452.1, for a coupon thickness of 3/4
inch and over, the qualified deposited weld metal thickness is "max to be welded". This assumes
only a single welder applying a single process is being considered. Note 1 points out that
multiple welders for the same coupon are only qualified to the extent of 2t for the weld metal
deposited by each welder with each process, and that these deposited weld metal thick nesses
need to be considered separately in the thickness column. I would also call your attention to
QW-351. It clearly states that a welder is qualified based upon the thickness of weld metal
deposited with each process.
-------------------------------------------------------------------------------34. - Material marking - VIII Div 1
Question: (1) Is UG-77 only applicable to plates ?
Question: (2) Is Marking and traceability of materials (UG-94) for all other product forms than
plates, is governed by the rules of UG-93(a)(2)?
Answer:
1. Only product form plate must be supplied with the complete marking per the material
specification. [UG-93(a)(1)]
2. For all other product forms, Section VIII-1 would accept reduced marking containing
specification designation, including the grade/type/class as applicable. [UG-93(a)(2)].
3. UG-77 applies to all material in the pressure vessel, independent of product form. However,
when employing a coded marking system to maintain trace ability of the material, one only needs
to be able to trace back to the original marking required by VIII-1; this means the marking
required by UG-93(a). This is stated in the 2nd sentence of UG-77(a).
4. While UG-93 addresses receiving inspection, UG-77 only deals with material identification
and trace ability during fabrication. Why would we need trace ability to more marking
information during fabrication than what was needed at the time of receiving? I recognize that
UG-77 uses the phrase .original identification markings required in the specifications, but I
believe we have to apply the test of common sense when dictating what amount of information
we need to have trace ability to. Therefore, it is my opinion that for all product forms other than
plate, the Manufacturer need only retain trace ability of the material to the original marking
information required at the time of receipt inspection per UG-93.
-------------------------------------------------------------------------------35. - Small Nozzle attachments - Section VIII Div1
Question: What about the legality of applying the attachment requirements of UW-16 (f)(3)(a)
when attaching a nozzle made of pipe materials with a single fillet weld from the outside only. Is
this permitted by the Code?
Response: This is not an appropriate paragraph to apply to a pipe nozzle. It is only intended to
apply to forged fittings with single fillet welds. The text of the paragraph refers only to fittings,
which is rather vague. Paragraph UW-16(e)(2) is a good fit for attaching such a nozzle to the
shell with fillet welding from the outside only. The following Interpretation supports this
application. This makes the weld sizing requirements a bit different, and requires a pretty tight
fitup.
-------------------------------------------------------------------------------36. - Welding Qualification Ranges
Question: What about the qualification ranges of QW-451.1 and QW-452.1? How do you
evaluate the qualified thickness range of a welder whose performance coupon was conducted
using a groove procedure for the full thickness of 3/4 inch base metal? The QW-452.1 table
seems to indicate that there is no maximum thickness limit on welder performance, but QW451.1 limits such a coupon to 2T (twice the coupon base metal thickness). What is correct?
Response: Welder performance limitations and procedure performance limitations are not the
same. Qualfied welding occurs when the welding is conducted with the qualified range limits of
welder performance and the procedure qualification. When both are satisfied, everyone is happy.
While successfully welding a 3/4 inch test coupon qualifies the welder for a "maxium to be
welded" or "unlimited" base metal thickness, unless he has a procedure qualified for the
thickness of base metal he intends to weld, he cannot weld it and be in compliance with the
Code. Mixing the procedure and performance qualification limits unintentionally is the most
common problem associated with using Section IX.
-------------------------------------------------------------------------------37. - Welding Questions
1: Question: Is it a necessity of qualifying a WPS for PWHT if the PWHT is applied as a nonmandatory requirement (not Code required) to improve machine ability of the vessel? Only a
PWHT type heat application is intended, and not an annealing heat treatment.
Answer: Application of PWHT is an essential variable for all welding processes per Section IX
of the Code. Since all the construction Codes require welding to be qualified per Section IX
(except where specified otherwise), this mandates the WPS to be qualified for the condition of
heat treatment applied to the production vessel to comply with the requirements.
2: Question: What about welding operator's qualified welding position in the following example?
The issue is, a welding operator for SAW process was qualified on a 1G position. The production
weld in question was a groove weld with a cover fillet weld on a tubesheet-to-shell weld welded
on a rotated flat positioner. According to QW-461.9 and QW-461.2 of Section IX, the cover
fillet weld was deposited in a horizontal position, for which the welding operator lacks
qualification.
Answer: To qualify for the production weld in question the welding operator, as minimum, needs
to pass a 2F or 2G position qualification test, or use the alternative rule in QW-305 by examining
the first 3ft of his production weld by radiography.
-------------------------------------------------------------------------------38. - "Coded markings" (Material) - UG-77(a), PG-77.2
Question 1: Can one unique No. be assigned to steel plates of same specification but with
different heat Nos. ?
Question 2: How about if the "plates" is substituted by "pipe or tube" in question one?
Response:
1. No. When traceability to the original markings or to a material test report is required, a coded
marking must be unique for a given specification and heat number of a material. If the plates are
of different thickness but of the same specification and heat, a common code marking may be
applied. If two plates have the same specification but different heat numbers, they must have
separate coded markings.
2. When material test reports are required, trace ability to the original markings is required.
When trace ability to the original markings or material test reports are not required. generic
marking identifying the material to a given specification is acceptable. For Section I
construction, it is generally understood that all pressure retaining materials require test reports.
For Section VIII, Division 1 test reports are only required for plate.
-------------------------------------------------------------------------------39. - Section I double block valves & free blow drains
Question: What are the actual requirements for a double block and free blow arrangement on the
steam isolation valves for a multiple boiler arrangement. The situation is a building with two
boilers installed, and connected to a common header. One is a 300 horsepower unit that is large
enough to have a manway installed. The second is a 40 horse unit that does not have a manway.
The larger boiler has a double block and free blow arrangement on it's steam outlet. The smaller
only has double block valves, without the free blow. Is this acceptable per the Code? What are
the references for the requirements?
Answer: Per Section I (PG-58.3.2) and B31.1 [122.1.7(A.3)]:"When two or more boilers are
connected to a common steam header, or when a single boiler is connected to a header having
another steam source (e.g., a turbine extraction line),the connection from each boiler having a
manhole opening shall be fitted with two stop valves having an ample free blow drain between
them." Double block valves with free blow drains are not specifically required for boilers that do
not have a manhole. The intent of this arrangement is for personnel safety. A single stop valve
has never been considered an adequate safety barrier for OSHA lock out and tag out
requirements. If it were to leak, a person inside a boiler could be subjected to steam intrusion.
Double block valves help to prevent such an intrusion. Since both valves may have some
leakage, the free blow drain is required to be open so that if the first valve leaks, it leaks to
atmosphere and does not put pressure on the upstream side of the second valve. There is no
provision for such an arrangement when installing boilers without manholes. The common
practice of interpreting the Code is to consider it to be permissive when silent, so long as such an
interpretation follows good engineering judgment. Therefore the smaller of the two boilers does
not require a free blow drain. By the same reasoning, it could not even require a second stop
valve. However, the Code doesn't prohibit the described arrangement. It is common for plant
arrangements for the piping to have double valve isolation capability for maintenance of
equipment.
-------------------------------------------------------------------------------40. - Pressure Relief Requirements - VIII Div 1
Question: What about the need to include something about the users' responsibility for relief
valves in the remarks section of Section VIII Data Reports?
Answer: It is not required for the Manufacturer to supply the pressure relief devices as stated in
UG-125(a) and as supported by the Interpretation below:
Interpretation: VIII-78-129
Subject:
Section VIII, Division 1, UG-134, Pressure Relief Valves
Date Issued: October 4, 1978
File: BC-78-583
Question (1): What are the requirements in Section VIII, Division 1 pertaining to set pressure of
pressure relief devices on vessels storing liquefied compressed gases and which satisfy the
conditions of UG-125(c)(3)?
Reply (1): Such relief devices may be set in accordance with UG-125(c)(3)(b) and UG-134
including the special provisions of UG-134(e)(2).
Question (2): Is it required that the vessel Manufacturer furnish the pressure relieving device(s)
prescribed by UG-125(a)?
Reply (2): No. Footnote 31 indicates that safety devices need not be provided by the vessel
Manufacturer, but overpressure protection shall be provided prior to placing the vessel in service.
Applicable urisdictional requirements should be reviewed to determine limitations which may be
different or more restrictive than the Code rules referenced in Question (1).
There are no requirements for the Manufacturer to provide any specific information regarding
the incorporation of pressure relief devices (PRD) on the data report other than to identify the
PRD opening provided on the vessel if an opening is so designated [see note 41 in Table W-3 of
Appendix W]. If the purchaser has not designated any opening as being specifically provided for
the attachment of a PRD, then sometimes the Manufacturer will put a statement in the remarks
something like "Pressure relief protection external to the vessel". This indicates that the vessel is
intended to be protected from overpressure by devices installed within the piping or other system
connections to which the vessel is attached. The responsibility for the correct installation of the
PRDs is the responsibility of the vessel user as stated in UG-125(a). Since users do not always
have Code books, it is a good idea for the Manufacturer to alert the user to this requirement in
any installation and operating instructions he may provide. The Jurisdiction will sometimes
provide this information, but in states which do not have a Pressure Vessel law, this may not be
the case.
-------------------------------------------------------------------------------41. -Section VIII Div 1 - seamless head "Quality Factor - E" Seamless Head "Quality Factor",
UW-11(a)(b)
Question: Customer inquired about the subject quality factor. He has a vessel with a single
course shell with a Category A double butt weld seam and a seamless head on both ends. The
head-to-shell joints are double butt Category B welds. The shell Category A weld was spot RT'd
per UW-11(b) and UW-52, hence he used E=0.85 for the shell (circumferential stress) thickness
calculation (UG-27). The question was, what is the examination required in order to use an
E=1.0 (in the UG-32 head formula) for the seamless head thickness calculation?
Answer: The reference is UW-11(a)(5)(b) which requires a spot RT per UW-52 on the Category
B head-to-shell joint and also the flow charts in Appendix L, p 525.
-------------------------------------------------------------------------------42. - Welding Position Section IX, QW-461.9
Question: A welding operator for SAW process was qualified on a 1G position. The production
weld was a groove weld with a cover fillet weld on tubesheet-to-shell weld welded on a rotated
flat position. Is the welding operator qualified for the production weld positions?
Answer: According to QW-461.9 and QW-461.2 of Section IX and the sketch supplied by the
contractor, the cover fillet weld was deposited in a horizontal position, for which the welding
operator lacks the qualification. To qualify for the production weld in question the welding
operator, as minimum, needs to pass a 2F or 2G position qualification test, or use the alternative
rule in QW-305 by examining the first 3ft of his production weld by radiography.
-------------------------------------------------------------------------------43. - VIII Div 1 - UW-13 head to shell alignment
Question: What if the vessel head to shell joint offset differs by more than 1/4 the thickness of
the thinner section or by more than 1/8", then does the subject par. apply, otherwise, the joint
shall be evaluated by UW-33? Is this correct?
Response: If the situation is similar to that shown in UW-13(b)(3). This paragraph describes the
requirements for a joint depicted in Figure UW-13.1 Sketches (l),(m),(n), and (o). Sketches (l)
and (m) are when the shell is thicker than the head, Sketches (n) and (o) are when the head is
thicker than the shell. Here is what the essence of the requirements are. If one element has a
thickness that is greater the other element (regardless of which one is the thicker element), by
more than the lesser of 1/4t (where t is the thickness of the thinner element) or 1/8 inch, a
mandatory tapered transition between the different thicknesses is required. This taper shall be at
a 3:1 ratio. The reference point for the taper is the tangent point of the head knuckle. The tangent
point is where the head acts more like a shell than a head under stress analysis. The shell shall
have the minimum required thickness on it's side of this point, and the head shall have it's
minimum required thickness on it's side of this point. Material may be added to either element to
achieve the transition taper as needed. But, material may not be removed from these elements
reducing either below the minimum required thickness on their respective sides of the tangent
point.
Example: A thick head is attached to a thinner shell. The head has a straight flange beyond the
tangent point. The required thickness of the straight flange in the area between the tangent point
and the attachment where it meets the shell is the required thickness for the shell. Since it does
not have the same required thickness as the head in this area, some of the excess material may be
removed to achieve the transition taper. Therefore, the straight flange may be tapered to
accomplish the required transition. If the difference in thickness is less than the lesser of 1/4t
(where t is the thickness of the thinner element) or 1/8 inch, no transition taper is required.
Centerline misalignment is controlled as well to limit a differential bending moment across the
joint around the circumference.
-------------------------------------------------------------------------------44. - QW-202.4 Combination Welding
Question: If welder welds a test coupon that is 1-1/2 inches thick, using two different welding
processes (GTAW and SMAW) for a deposited weld metal thickness of 3/4 inch for each, what
are the limits of qualification for this coupon for procedure and performance? Is it possible for
the welder to weld the coupon in more than one position, say 2G and 3G, and get benefit for both
in qualification limits?
Response: Question 1: Qualified Procedures may be used in combination, or a single procedure
with multiple processes may be qualified. If applying the situation as described, the limits of
qualification are:
Procedure: Base metal thickness: 3/16 to 8 inches; Weld metal thickness: GTAW and SMAW
both qualified for 8" max (if 3/4" min. deposited)
Performance: Weld metal thickness: GTAW and SMAW both qualified for "Max to be welded"
Question 2: The coupon could be partially welded in one position and then another position, with
the qualified weld metal thickness limits for each position based on the actual weld metal
thickness deposited in each position. Example: Same coupon described as above. Weld in 2G
position with 3/8" GTAW and 3/8" SMAW, change the position to 3G and weld 3/8" GTAW and
3/8" SMAW again. If the coupon successfully passes the required tests, the welder would be
qualified to weld in 1G, 2G, or 3G using GTAW and SMAW with a qualified deposited weld
metal thickness of 3/4" maximum for each position. Only the first process (GTAW) would be
qualified without backing, and then only in 2G and 1G. SMAW would be qualified with backing
only in positions 1G, 2G, and 3G. GTAW is qualified in 3G with backing only.
-------------------------------------------------------------------------------45. Material Certification
Question about a material acceptability issue. The shop rolled and welded a shell out of ASME
Material, and documented their work on an ASME Partial Data Report. The shell was received
by the purchaser, who was sent a copy of the Material Test Report (MTR) along with the Partial
Data Report. They were balking at accepting the part, because the MTR had a different Edition
and Addenda for the material specification than the Current Edition and Addenda as listed on the
Partial Data Report. Is this a problem?
Response: Editions and Addenda's do not apply to Material Specifications. ASME Materials are
always acceptable as ASME Materials. If the newly published specification has more restrictive
requirements than the material was manufactured to, this needs to be evaluated. If the material
has an ASTM Specification date on it, this can be checked against Appendix A of the Section II,
Part A book for acceptability of the date code. If only designated with an ASME Specification
number, it is acceptable under that specification. This is addressed in the Foreword of the Code
books, where it discusses Addenda, and states "Revision, except for revisions to material
specifications in Section II, Parts A and B, become mandatory six months after the date of
issuance,…". It is the intent of this statement to specifically exempt the material specifications
from the Addenda mandatory implementation date. New materials shall always be ordered
against the current Code requirements, but materials in inventory are acceptable under their
material designation if ASME Spec material.
-------------------------------------------------------------------------------46. Welder Continuity and Qualification
Question: A welder that was an employee before, left the company and went to weld for another
firm, and then came back. The period away from the company was greater than six months. The
first company (original qualifier) wanted to reinstate the welder as fully qualified, based upon a
phone conversion with the interim employer stating that the welder had been continuously
welding. Is this acceptable?
Response: This is not in keeping with the letter or intent of the Code. Welder qualifications are
specific to an employer, unless a pooled qualification scheme has been applied as stated in QW300.2 of Section IX. A pooled qualification scheme does not appear to be the case here. The
welder's continuity gap with a specific employer exceeds six months, requiring re-qualification
under the provisions of QW-322.1. The re-qualification is very simple, requiring the welder to
weld only one coupon with a given process per QW-322.2(a). If the coupon passes the
requirements of QW-301 and 302, the welder is fully reinstated in that process for all of his
previous qualification ranges. The test may be a simple as a spot RT on a production weld, or
two bend tests on a test coupon. This can be done for all processes previously qualified. For
those processes not previously qualified, or when the qualifications have been revoked for cause
per QW-322.1(b), full qualification tests are required.
-------------------------------------------------------------------------------47. - Section VIII Div 1 - "Low Temperature Vessel"
Question: What defines a "low temperature service" vessel? If a vessel is considered a low
temperature service vessel, what requirements are to be met?
Response: All of the following are considered to be "low temperature service" vessels:
1. Vessels made of Part UCS materials with an MDMT of colder than 55F and have a coincident
ratio of greater than 0.35, as set forth in UCS-68(a).
2. Vessels made of Part UHA materials that require impact testing of the base metal or weld
metal per the rules of UHA-51.
3. Vessels fabricated under the rules of Part ULT of Section VIII, Division 1.
For vessels in categories (1) or (2) above, the provisions of UW-2(b) must be met. These
provisions limit weld joint of specific Categories to a specific joint type. Vessels in category (3)
above need to meet the requirements of Part ULT.
-------------------------------------------------------------------------------48. - Calibration of pressure gauges
Question: What is ASME's policy is with respect to the calibration of pressure gauges for:
* New construction pressure testing (non nuclear)
* In-service pressure testing and testing and setting of safety valves. (NBIC) (Boilers, air
receivers, pressure equipment generally)
Is it required that these pressure gauges to be traceably calibrated back to a national standard?
Answer: The AI is required to verify that the Manufacturer follows their QC Manual, which is in
line with our role as an Authorized Inspection Agency. The QC Manual is written in accordance
with the applicable sections of the Code that the fabricator deals with. Each of the ASME Nonnuclear Boiler & Pressure Vessel Codes has specific paragraphs regarding calibration of test
equipment. Essentially they say it has to be done and traceability maintained but do not specify a
standard. For example, Section VIII, Division 1, UG-102(c) states "All pressure gages shall be
calibrated against a standard dead weight tester or a calibrated master gage. Gages shall be
recalibrated at any time that there is reason to believe that they are in error." Except for Section
VIII, Division 2 & 3, which require recalibration every 6 months, there are no references to
frequency or specific standards. Section III (nuclear) requires recalibrating before each test or
series of test (anything within 2 week period). Although it is not specifically stated in any of the
code books, it is commonly understood and industry practice that the Manufacturers use some
nationally recognized standard for calibration and how the records/certifications can be traced
back to the standard and state so in the QC Manual. This national standard that is used may be
one established by the National Institute of Standards and Technology (NIST) or any other
agency recognized by a government as a standards organization (i.e., they may use NIST, DIN,
JIS, etc.). I believe the ASME changed this so that it was not nation specific (restraint of free
trade and all that). In-service testing would be the same. The requirement would be included in
the owner's or repair organization's QC manual. As far as testing/setting of safety valves this
would fall under the Valve Repair organization's manual. Again this would reference a specific
national standard and some frequency for recalibration.
-------------------------------------------------------------------------------49. Tube hole deburring - Section IV
Question: What about requirements to deburring tube holes in Section IV boiler construction.
The tube to header attachment is by welding as shown in Figure HW-731, sketch (y). The
requirements for deburring are found in HG-360.1(b). Similar requirements are found in HLW309(a), but are addressed to rolled tube attachments only. Should this be necessary for welded
attachments?
Response: The Code does not specifically limit this requirement to rolled attachments. The
primary objective of deburring the hole edges is to minimize the cutting effect they would have
on the tube when rolling, and removing anything that would interfere with a solid seating of the
tube into the hole. No personnel safety issues are at stake for tube to header welds, since header
entry is not likely. Considering the context of HG-360.1, and the presumed reasons for requiring
deburring, it seems unreasonable to require deburring of tube holes for welded tube attachments.
Tube to header attachments per Figure HW-731 sketch (y) are acceptable without deburring.
-------------------------------------------------------------------------------50. Calculated Test Pressure - VIII Div1
Question: How do you determine the "New and Cold" MAWP of a Section VIII, Division 1
vessel. The owner wants to have the New and Cold MAWP included on the nameplate as well as
the traditional MAWP. How is this determined, and why would the purchaser need this
information?
Response: The "New and Cold" MAWP is the value determined as the basis for a calculated
test pressure as discussed in UG-99(c). It references the reader to Appendix 3, which defines a
calculated test pressure as "the highest permissible internal pressure as determined by the design
formulas, for each element of the vessel using the nominal thicknesses with the corrosion
allowances included and using the allowable stresses given in Section II, Part D for the
temperature of the test." In this case, the MAWP calculated for the most limiting component
times the multiplier of 1.3 would be the basis for the calculated test pressure, and no stress ratio
would be applied. The reasons for needing this information are unknown, but an educated guess
would be for the purpose of conducting an acceptance pressure test upon the system after
installation and connection to piping components. Often piping test pressures are limited by
installed component MAWP, and the purchaser may want to minimize the limiting influence of
the vessel MAWP on the system acceptance test. Be sure that the nameplate clearly indicates the
different MAWPs as being either new and cold and operating values. Also remember that the
marked MDMT is based upon the operating MAWP.
-------------------------------------------------------------------------------51. - VIII Div 1 - Vacuum, RT- nameplate
1.Question: Is it acceptable to mark a vessel with a "FV" rating on the nameplate? The
Manufacturer wants to know if putting "-15" (minus fifteen) was acceptable. Is it permissible to
mark supplementary information on a nameplate?
Response: Marking a vessel rated for both internal and external pressure in a manner such as
"MAWP 150 and FV at 400F" is a long standing industry practice, and acceptable. An
alternative method is to mark it "MAWP 150 (INT)/15 (EXT) at 400F". Putting a negative
pressure such as -15 on the vessel is so contrary to standard practice that I do not recommend it,
as it might be too ambiguous. Supplementary information may be added to a nameplate by the
Manufacturer, provided that the required information and formatting shown in Figure UG-118 is
not interfered with. Such information should appear at the bottom of the nameplate. The only
thing that should appear above the "certified by" is the National Board No. when so registered.
2. Question: What is the correct RT designator for a Section VIII, Division 1 U-tube heat
exchanger shell per UG-116(e). Vessel has a seamless shell, seamless head on one end attached
with a Type 2 weld joint that is fully radiographed, and a slip on flange on the other end attached
by double fillet welds. Is this RT1 or RT4?
Response: This is RT1. All butt welds in the vessel have been subjected to a full radiography,
meeting the requirements of UW-11(a). This is the criteria of UG-116(e)(1) for RT1.
52. SAW welding procedure Changes, PQR requirements for Corrosion Resistant Overlay
1.Question: What is required to revise a SAW procedure to change from double welding a joint
(with back gouging before welding the backside) to single welding using a ceramic tape
backing? Is there a qualification issue here?
Response: Joint design is not an essential variable, and neither is the addition or deletion of
backing, so re-qualification of the WPS is not required to make this revision. Some revisions in
the heat input may be required, such as adjusting the electrode diameter, amperage, and travel
speed to get good burn through and fusion in a single pass. This would have qualification
implications for an impact test qualified procedure. There are no qualification implications for
welder performance.
2.Question: What is the correct interpretation of QW-404.37. The Manufacturer has a corrosion
resistant weld metal overlay procedure qualified for the SMAW process using E309L electrode.
He was wondering if the change in electrode designation from E309L to another alloy such as
E316L would require a new PQR be prepared. The filler metals have the same A-No. and F-No.,
but QW-404.37 tends to indicate that for A-8 and A-9 weld metal analysis, a change of AWS
classification requires re-qualification.
Response: Yes this is a correct interpretation of QW-404.37. A change in AWS classification
requires re-qualification.
Flux trade name LINCOLN:760/Flux Type: ACTIVE
3. Question: One of my clients was told that the above type of flux is not allowed for Subarc
welding because that it adds alloy?
What is the correct answer?
Response: Changing from an active to a neutral flux or vice versa requires re-qualification per
QW-404.34. Fluxes that add alloying elements are acceptable once qualified under Section IX
requirements. The variables addressing alloy fluxes are QW-404.10 and QW-404.27, which are
both essential variables. These are not normally addressed when fluxes that do not contain
alloying elements are used.
-------------------------------------------------------------------------------53. Inspection Openings - VIII Div 1
Question: What about the requirements for inspection openings per UG-46 in Section VIII,
Division 1. The vessel in question is 42" ID, and 11 ft. long, with elliptical heads attached, that
has only two 2 inch openings in the bottom head. Is this acceptable?
Answer: This is an acceptable condition if the vessel is intended for non-corrosive service. If so,
the data report needs to state "For Noncorrosive Service" in the remarks section per UG-46(a)(4).
-------------------------------------------------------------------------------54. - Root pass WPS - QW-200.4(b)
Detail: Does a WPS for a root welding process qualified on a 3/8 inch coupon which is then to
be applied in a 1 inch production base metal thickness weld meet the QW-200.4(b)
requirements?
Response: For a root process to be applied, it must meet the qualified base metal thickness
ranges of QW-451, or have been qualified on a coupon at least 1/2 inch thick for unlimited base
metal thickness applications. The example cited can be used as a root pass weld for metal up to
3/4 inch thick without additional qualification. The basis of this requirement is a phenomenon
known as the "3D cooling effect". There is a fundamental difference between the heat dissipation
rates in thin metals and thick metals. The difference occurs due to the available paths of
dissipation within the base metal during welding. At thicknesses around 1/2 to 5/8 inch and less,
the thickness of the material acts as a bottleneck to the flow of conductive heat in the metal. At
greater thicknesses, the cross sectional area is great enough that the heat flux is not constricted
and flows more freely, hence the 3D effect. Cooling rate has a great deal to do with fusion
properties of welds, as well as the structures formed within the weld and HAZ. This is why
impact testing requirements and qualified base metal thicknesses are based on the thickness
qualified.
-------------------------------------------------------------------------------54. - Boiler External Piping – design
Question: How do you verify the adequacy of a spool piece design for a Section I boiler
installation, with a MAWP of 600 psi and design temperature of 489F. Safety Valve settings are
570 and 595 psi? The spool piece consists of SA-106B seamless pipe with an ASME B16.5 Cl
600 flange on the inlet and a Cl 300 flange on the outlet. At issue is the acceptability of the Cl
300 flange, which is present to allow connection with the client's Cl 300 flanged valve in the
steam system.
Is this design adequate for the conditions cited?
Response: Yes. The Cl 300 flange is good for 600 psi at 500 F, and the design requirement of
B31.1 paragraph 122.1.2 (A.1) requires the design to have a value of "P" that is not less than the
lowest set safety valve setting. Since this value is 570 psi, the flange is acceptable.
-------------------------------------------------------------------------------55. Use of SA 36 - VIII Div 1
Question: What about the acceptability of SA-36 for use in fabricating pressure vessels? Some
people have been questioning this, and pointing out that the Scope of the material is structural. Is
there a problem with using this material?
Response: This material is acceptable for use within the restrictions of Paragraph UCS-6 of
Section VIII, Division 1.
Question: Are there any restrictions on the use of SA-36 material in Section VIII, Division 1?
Reply: The only restrictions on the use of SA-36 material is on plate called out in UCS-6(b) and
specifically UCS-6(b)(4) of Section VIII, Division 1. These restrictions prohibit the use of such
plate material where strength welding is applied and only for heads, shells, and nozzles which
exceed 5/8 in. in thickness. There is no restriction on the use of SA-36 bar stock.
Question: Is it permissible under the requirements of UCS-6(b) in Section VIII, Division 1 to use
SA-36 plate material in thicknesses over 5/8 in. in the construction of welded covers, similar to
that shown in Fig. UG-34 sketch (g)?
Reply: No. In addition, there has been a recent action to remove the penalty applied to the
allowable stress values for structural materials. There has been an error in Table 1A for the past 3
years with respect to SA-36 allowable stresses. It all started when Section II decided to publish
the values unadjusted by the 0.92 quality factor, and then rely on General Notes to apply the
factor for pressure applications. However, somewhere along the line the applicable note
[currently G37] was dropped. Customers should use the values as published, and not apply the
0.92 factor, although Table 1-100 says it should be applied. The information supplied in
Appendix 1 is for information only; code users should not have to review this material in order to
figure out what allowable stress to use. This problem will finally be put to rest in the upcoming
2000 Addenda, when the 0.92 penalty factor will be deleted from Table 1-100, and dropped for
all cases.
-------------------------------------------------------------------------------56. Nozzle replacement - VIII Div 1
Question is about a "repair" replacing a NPS 1-1/2 coupling with a NPS 3 SCH 10 pipe stub in
the head of a Section VIII, Division1 vessel. Head is 0.3125" thick. Vessel rated at 150 psi for 20 to 650F. Nozzle attachment detail per Figure UW-16.1 sketch (i). The concern is about the
thickness of the nozzle being from a pipe stub, since it is not as heavy as a coupling, and the fact
that a SCH 10 pipe was specified. Is there any problem with this?
Response: Yes, the thickness will not meet the requirements of UG-45. The wall thickness
needs to be either the same as the shell or head that it penetrates or Sch 40 (STD), whichever is
less. Since SCH 40 for this size pipe is 0.216 inches, which is less than the head thickness, this is
the minimum wall thickness needed. For the stated head thickness, this diameter of opening may
be attached without reinforcement calculations unde the provisions of UG-36(c)(3)(a), and the
weld strength can be exempted from calculations per UW-15(b)(2). Since this is a new opening
size for the vessel and not a like-for-like replacement, it is an Alteration and not a Repair.
-------------------------------------------------------------------------------57. DA Tank - small nozzle welds
Inspector did a DA tank internal inspection and noted three nozzles were not full penetration
welded. These three nozzles used a fitting that is fillet welded from the outside only with just a
hole in the shell on the inside. Shouldn't DA tanks nozzles be full penetration and welded as
such? I know the code allows the fillet type fitting, but isn't it good engineering practice to use
full penetration type nozzle?
Response: Fittings less than NPS 3 may be attached with a single fillet weld from the outside
only per UW-16(f)(2). The welds may actually be quite small and still be acceptable. In addition,
UG-36(c)(3)(a) permits these openings to be installed without having to evaluate them for
sufficient reinforcement, and UW-15(b)(2) exempts them from weld strength calculations.
Assuming that these "fittings" are in fact couplings, half couplings, threaded bushings or some
other forged type of pipe fitting. If this is not the case (i.e.; the nozzles are pipe segments), UW16(f)(2) cannot be applied. Pipe segments can only be attached with full penetration groove
welds or double full fillet welds. Another potential problem is if they are too closely spaced.
They must be spaced at a distance of not less than twice their average diameters (center-tocenter) or they will be subject to some additional requirements.
-------------------------------------------------------------------------------58. - NCRs - Section I and VIII Div 1
Question: What is an "NCR" in an ASME QC Program? (Ref: ASME Section VIII Div 1
Appendix 10-8, ASME Section I A-302.6)
Answer: The ASME Code requires the Manufacturer to have a system for identifying and
resolving nonconformances, but does not specify how to do so. The Code intentionally leaves
this open to the Manufacturer to decide, since nonconformances may vary considerably from job
to job. The nonconformance system shall be described in the Manufacturer's Quality Control
Program, and shall be followed. Once a nonconformance has been identified on a NCR, this
usually involves having the engineering department and/or manufacturing propose a resolution to
the NCR. The NCR is reviewed for acceptance of the proposed corrective action by the QC
Manager and AI, who are responsible for verifying Code compliance. There are typically three
choices that apply to resolving a NCR. They are: 1. Scrap, 2. Rework, or 3. Use as is. For the
instances cited, the proposed resolution should be to "use as is"; with the additional actions of
either providing a marked up copy of the drawing or some other documentation of what was
done differently than specified during production. Many firms use a "deviation" document. This
document reports and documents a "one time" change to the drawing or specifications for a
particular vessel or series of vessels, and documents approval of those changes. This becomes a
permanent part of the job package. The NCR should also become a permanent part of the job
package as well. Then, additional care needs to be taken to ensure that the Manufacturer's Data
Report properly documents the specifications of the vessel. In the case of the actual head
thickness, this is not an issue, since the minimum specified head thickness is recorded, not the
actual thickness. A change in reinforcement material may need to be properly recorded on the
Data Report (ie nozzle or shell), and calculations need to be adjusted to verify the suitability of
such a change.
--------------------------------------------------------------------------------
59. WPS qualification with impacts
Question: When impact tests are required to be added to an existing WPS, a new test coupon has
to be welded for the impact testing. Does the new test coupon also have to have complete
physical tests if all parameters fall within the limits of the original WPS?
Response: No, the other mechanical testing is not required. If the coupon was welded following
all the currently qualified essential variables merely to expand the qualification to include
toughness applications, the impact test alone is sufficient to qualify the current WPS for
toughness. The WPS should be revised to address the supplementary essential variables applied
to the test weldment, and to reflect the new supporting PQR as well.
Question: When a change is made in a Supplementary Essential Variable for work done
according to a Section which specifies notch toughness tests, are tension, bend, and impact tests
required or only weld deposit and heat affected zone impacts?
Reply: When a change is made in a Supplementary Essential Variable for work done according
to a Section which specifies notch toughness tests, all tests are not required to re-qualify the
procedure.
The second paragraph of QW-403.5 states:
When a procedure has been previously qualified to satisfy all requirements other than notch
toughness, it is then necessary only to prepare an additional test coupon using the same
procedure with the plates only long enough to provide the necessary notch toughness specimens.
If a previously qualified weld procedure has satisfactory notch toughness values in the weld
metal then it is necessary only to test notch toughness specimens from the heat affected zone.
Question: If a welding procedure has already been qualified to satisfy all requirements other than
notch toughness and a new procedure is to be qualified without changing essential variables but
incorporating additional supplementary essential variables, will it be necessary to prepare an
additional test coupon using the new procedure, only to provide necessary notch toughness
specimens?
Reply: Yes.
-------------------------------------------------------------------------------60. Section I - connection off water column, & B31.1 valve
1.Question about connections in a FTSM Section I boiler. Apparently a repair/installation
company wants to put a steam connection on the water column in a dry cleaners. They want to
install piping that would take the steam for warm-up purposes for some of the equipment in the
store. Is this permitted?
Answer: PG-60.30.4 and PG-60.3.8 are paragraphs that address connections for the water
column. PG-60.3.4 discusses the piping sizes and states that "These connections shall be
completely independent of other connections for any function other than water level indication".
PG-60.3.8 states "No outlet connections, except for control devices... or apparatus of such form
as does not permit the escape of an appreciable amount of steam or water therefrom shall be
placed on the piping connecting the water column or gage glass to a boiler".
2.Question: How do you determine the valve pressure rating for a blowoff B31.1 valve?
Answer: Example: Per B31.1, paragraph 122.1.7(C.6), the pressure rating of the flange or valve
must be increased by 25%. Therefore, for a blowoff line with a MAWP of 325 psi, the pressure
rating must be greater than 406 psi (325 x 1.25=406). A 300# flange has a rating of up to 490 psi
for blowoff piping. This would be ok for a water temperature up to about 486 F. This is based
on the fact that the same class rating (300#) is acceptable for steam use up to 605 psi. The
saturation temperature of steam at this pressure is about 486 F. The temperature of water at 406
psi is about 445 F.
-------------------------------------------------------------------------------61. PWHT - placement of thermocouples VIII Div 1
Question: What are the requirements regarding the number of thermocouples for PWHT
(postweld heat treatment) in accordance with UCS-56 of ASME Section VIII Div.1? When
PWHT is to be carried out, the proper number of thermocouples shall be attached to the parts or
vessel surface. How many numbers of thermocouples should be attached to the vessel in a
furnace? Is it sufficient for furnaces to have been calibrated by qualification block attaching
thermocouples with 15ft interval of length annually? Are four(4) or five(5) thermocouples in a
furnace are sufficient for PWHT regardless of item size?
Response: The only requirements for thermocouple placement are found in UW-40(c). It
discusses the placement of thermocouples near the top, middle, and bottom of the charge, to
ensure true metal temperature indication for all zones when more than one vessel is included in
the oven charge. Referenced footnote 10 states that furnace gas temperature measurement is
insufficiently accurate to use as a guide. It is intended that the time at temperature shall be based
on the metal temperature, not the oven temperature, otherwise the PWHT will be ineffective. So,
a specific number of thermocouples for a given oven charge is not specified. But, based upon the
guidance of UCS-56, sufficient numbers of thermocouples need to be present to verify that the
thermal gradient limitation of 250 F (139 C) within a distance of 15 feet (4.6 m) is not exceeded
during the heating period [per UCS-56(d)(2)], and to ensure that the temperature difference
between the highest and lowest temperatures of any parts being PWHT does not exceed 150 F
(83 C) [per UCS-56(d)(3)].
-------------------------------------------------------------------------------62. In process inspection by the AI? - VIII Div 1
Question: Can the AI get by with "no" in-process inspections of a pressure vessel during
fabrication?
Answer: We do not believe that the intent of the Code is being met when an AI performs no inprocess inspections. Yes, there are many items in UG-90(c)(1) which require the AI to "verify"
that a Code requirement has been complied with, but which do not necessarily require an inprocess inspection in every case. However, as a minimum there are some inspections that must
always be performed, such as:
UG-93(a)(1) The Inspector shall examine the Material Test Report or certificate of compliance
and shall determine that it .
UG-94 The Inspector shall inspect materials used in the construction
UG-97 When conditions permit the Inspector shall perform an internal inspection, and he shall
make an external inspection at the time of the hydrostatic test.
UG-90(c)(1)(j) Making a visual inspection of vessel to confirm that the material identification
numbers have been properly transferred.
UG-90(c)(1)(k) Making a visual inspection of the vessel to confirm that there are no material
with dimensional defects.
This is not a complete list for Section VIII-1, but it does show that the Code mandates a
minimum amount of in-process inspections.
-------------------------------------------------------------------------------63. WPS for Dissimilar Thickness Joint
Question: An ASME Code stamp holder called about a Welding Procedure Specification for a
dissimilar thickness joint they were reviewing. The weld is a set-on [Figure UW-16.1(a)] 20
inch diameter nozzle with 1.281 inch wall thickness to a shell with 1.812 inch wall thickness.
Both base metal are P-No.1. The WPS assigned to weld the nozzle to shell joint has a maximum
qualified base metal thickness of 1.5 inch. Is the WPS acceptable to use on this joint?
Answer: No, the Welding Procedure Specification is not acceptable per QW-202.4. The welding
procedure must have both base metal thickness, nozzle and shell, within its qualified range.
Question: Is PWHT required for the same joint?
Answer: They should determine the nominal thickness from UW-40(f), which is the greater of
the nozzle groove weld size and fillet weld throat dimension, to evaluate whether PWHT is
required.
-------------------------------------------------------------------------------64. RT designator Section VIII Div1?
1.Question: This is regarding a vessel that has a smls pipe shell and smls (one piece) elliptical
head. The girth was single spot RT examined at time of mfg and the nameplate was stamped
RT-3. If the vessel is altered, can a spot be taken on the girth again (either single spot or double
spot)and call it RT-2 as well as claim the increased joint efficiency to increase the MAWP as
part of the alteration?
Answer: RT-3 is the incorrect designation for the original vessel. The correct marking should be
RT-2 if all the following are correct:
1. seamless shell and two seamless heads
2. Category B girth welds are Type 1 or 2, welded by a single welder, and combined length less
than or equal to 50'
3. A single spot x-ray taken on one of the girth seams per UW-11(a)(5)(b)
4. Design Efficiencies: Shell Circumferential stress - E = 1.0 for Type 1, E = 0.9 for Type 2
Shell Longitudinal Stress - E = 0.7 for Type 1, E = 0.65 for Type 2, Seamless heads - E = 1.0
Although the joint efficiencies for longitudinal stress are less than 1.0, this will not control the
design, since the longitudinal stress is one-half the circumferential stress when pressure is the
only load. You don't describe the extent of the alterations, or whether it will require further RT.
Assuming the answer is no further RT is required, then you can increase the MAWP for the
vessel based on the information provided above; the nameplate and data reports should be
corrected to RT-2, etc.
2.Question. A rolled and welded shell has seamless heads attached. The shell to head joints are
given spot radiography to allow the heads to be calculated with E=1.0. What RT designator fits
this situation?
Response:2. RT-4 is the best fit. RT 3 does not apply, since the long seam is to be left as welded
without examination.
-------------------------------------------------------------------------------65. Lifting Lug calculations VIII Div 1
Background: During an ASME Joint Review for a "U" Certificate of Authorization it was noted
by the ASME Team Leader that no calculation was made for the lifting lugs which were welded
directly on the vessel wall. He pointed out that this is a Code deficiency in the light of paragraph
UG-22, and asked the stamp holder to issue an NCR and prepare the calculation.
Question: Does the Code require the calculation be made for lifting lug when it is welded
directly on the vessel wall?
Answer: ASME has previously issued the following interpretation for this situation:
Interpretation: VIII-1-98-81
Subject: Section VIII, Division 1 (1998 Edition, 1998 Addenda); U-1(e)(2)
Date Issued: September 10, 1999
File: BC99-373
Question: Are the calculations for lifting of the vessel considered a part of Code, Section VIII,
Division 1, design calculations and required to be made available to the Authorized Inspector?
Reply: No. When a lifting lug is welded directly to a vessel, the scope of the vessel ends with the
attachment weld. The only time we would consider any reaction loads at the lug attachment point
is during pressurized operation of the vessel, where these reaction loads may produce stresses
which are additive to pressure induced stresses. However, if the lift lugs are solely used to move
the vessel, then as stated by VIII-1-98-81, these are not Code mandated calculations.
-------------------------------------------------------------------------------66. - VIII Div 1 - Opening Reinforcement Calculations
Question: Regarding a blind flange design:
The C of A Holder submitted a design to their customer for review, and they rejected it based on
incorrect reinforcement calculations. Looking over the customer's drawing for this vessel and
cover; indeed they have an 2" NPT and 1/4" NPT spaced at 2.311", which is slightly closer than
that permitted by UG-36(c)(3)(c), which is the sum of their diameters (2.625"). The C of A
holder missed this, and did not run reinforcement calculations. Unless their cover plate is
designed such that tr = tn, they should be able to satisfy reinforcement calculations for each
opening using a smaller set of limits.
Answer: This question is about exemptions from reinforcement calculations for small openings.
Oil separators use a bolted blind flange for one of their closures. These blind flanges have
several NPT fittings installed in them. The question deals with the application of the UG36(c)(3) and UG-36(c)(3)(c) reinforcement exemption and spacing requirement for these small
openings. If you look at the C of A holder's drawing, they would position a 1/4" NPT near a
larger 2" NPT. The two openings are spaced too close to meet UG-36(c)(3)(c); however,
calculations can be performed for the 1/4" NPT which would show it to be adequately
reinforced. If this is done, then is there any need to perform reinforcement calculations for the 2"
NPT, since the spacing requirement of UG-36(c)(3)(c) is for two UNREINFORCED openings,
and we now only have one unreinforced opening, the 2" NPT?
-------------------------------------------------------------------------------67. VIII Div 1 - production impact test?
Situation: A vessel is being built to Section VIII-1. MDMT -50F
Shell material is SA-350 LF2 1.63" nom.
Flat head material is either SA- 516GR 70N Impact tested to -50 or SA-350 LF2[ 2" nom.]
WPS is a combination (short circuiting GMAW and FCAW) and has been impact tested to -50 F
Welding consumables are GMAW ER70S-2 and FCAW E71T-1 neither of which
is impact test certified to -50 F.
Question:. Are production impacts required to meet UCS-67?
Answer: Based on the information presented, the Welding Procedure Qualification shall include
impact tests of the weld and HAZ, since none of the paragraphs of UCS-67 provide an
exemption. Specifically UCS-67(a)(2) does not waive qualifying the WPS with impacts since the
welding consumable use was not classified by impact tests at the MDMT by the applicable SFA
specification. Per UG-84(i)(2), once the WPS has to be qualified with impacts, then production
impact tests are also required. The rules of UG-84(i) shall be followed regarding the production
impact tests.
-------------------------------------------------------------------------------68. Impact Test Exemptions for ERW Pipe
Except as exempted in UG-20(f), UCS-67(b) requires impact testing of Weld Procedure's of
welds made without the use of filler metals if the weld exceeds 1/2" for all MDMT and when the
weld exceeds 5/16" with MDMT colder than 50 deg F.
Question 1) Does this apply to ERW Pipe supplied by a pipe manufacturer? If the answer is no,
is this by ASME interpretation?
Question 2) If the answer to question 1 is yes, how does a Certificate holder obtain certification
of this?
The below interpretation was the response:
Interpretation: VIII-1-89-322
Subject: Section VIII, Division 1 (1989 Edition); UG-20(f) and UCS-67
Date Issued:
January 9, 1991
File:
BC90-683
Question: When material is exempted from impact testing by UG-20(f) of Section VIII, Division
1, must impact tests per UCS-67 be performed on the longitudinal welds of SA-53 ERW pipe in
thickness up to and including 1 in.?
Reply: No.
The rational for this response is that when you purchase ERW pipe, you are essentially
purchasing material; the vessel Manufacturer is not responsible for the autogenous weld. Also,
UCS-67(b) would also not apply if UCS-66(a) or (b) were used to establish the impact test
exemption. In my opinion the only time UCS-67(b) would apply is when the Manufacturer
makes the weld himself.
-------------------------------------------------------------------------------69. Section IX Welder Qualification using S numbers
Question: Client is using A-36 for qualification of welders for use in ASME Code construction.
Is this acceptable?
Answer: Per QW-420.2 (last para), qualification interchangeability between P No's and S No's is
acceptable i/a/w QW-403.18. This is an essential variable that applies to all welding processes in
Section IX. QW-403.18 also references QW-423. QW-423.2 allows for welder qualification
using any material (to a natl' or internatl' spec, e.g. DIN spec) as long as it meets the mechanical
and chemical requirements of the target P or S No. Therefore, since Section IX allows for the
interchangeability of P and S No's for welder qualification, use of A-36 is acceptable to qualify
Code welders. The fact that the addenda year is not listed for the A-36 material is a moot point.
The listing of a specification year and addenda is not a requirement for Section IX purposes as it
is in the referencing book sections. Further, the wide latitude of acceptable materials used for
performance qualification in Section IX confirms that the particular material does not have as
much importance in the qualification as other variables do that confirm a welder's ability to make
a sound weldment.
-------------------------------------------------------------------------------70. VIII Div 1 - production impact test?
Situation: A vessel is being built to Section VIII-1. MDMT -50F
Shell material is SA-350 LF2 1.63" nom.
Flat head material is either SA- 516GR 70N Impact tested to -50 or
SA-350 LF2[ 2" nom.]
WPS is a combination (short circuiting GMAW and FCAW) and has been
impact tested to -50 F
Welding consumables are GMAW ER70S-2 and FCAW E71T-1 neither of which
is impact test certified to -50 F.
Question:. Are production impacts required to meet UCS-67?
Answer: Based on the information presented, the Welding Procedure Qualification shall include impact
tests of the weld and HAZ, since none of the paragraphs of UCS-67 provide an exemption. Specifically
UCS-67(a)(2) does not waive qualifying the WPS with impacts since the welding consumable use was not
classified by impact tests at the MDMT by the applicable SFA specification. Per UG-84(i)(2), once the
WPS has to be qualified with impacts, then production impact tests are also required. The rules of UG84(i) shall be followed regarding the production impact tests.
-------------------------------------------------------------------------------71. Impact Test Exemptions for ERW Pipe
Except as exempted in UG-20(f), UCS-67(b) requires impact testing of
Weld Procedure's of welds made without the use of filler metals if the
weld exceeds 1/2" for all MDMT and when the weld exceeds 5/16" with
MDMT colder than 50 deg F.
Question 1) Does this apply to ERW Pipe supplied by a pipe
manufacturer? If the answer is no, is this by ASME interpretation?
Question 2) If the answer to question 1 is yes, how does a Certificate
holder obtain certification of this?
The below interpretation was the response:
Interpretation: VIII-1-89-322
Subject: Section VIII, Division 1 (1989 Edition); UG-20(f) and
UCS-67
Date Issued:
January 9, 1991
File:
BC90-683
Question: When material is exempted from impact testing by UG-20(f)
of Section VIII, Division 1, must impact tests per UCS-67 be performed
on the longitudinal welds of SA-53 ERW pipe in thickness up to and
including 1 in.?
Reply: No.
The rational for this response is that when you purchase ERW pipe, you
are essentially purchasing material; the vessel Manufacturer is not
responsible for the autogenous weld. Also, UCS-67(b) would also not
apply if UCS-66(a) or (b) were used to establish the impact test
exemption. In my opinion the only time UCS-67(b) would apply is when
the Manufacturer makes the weld himself.
-------------------------------------------------------------------------------72. Section IX Welder Qualification using S numbers
Question: Client is using A-36 for qualification of welders for use in ASME Code construction.
Is this acceptable?
Answer:
Per QW-420.2 (last para), qualification interchangeability between P No's and S
No's is acceptable i/a/w QW-403.18. This is an essential variable that applies to all welding
processes in Section IX. QW-403.18 also references QW-423. QW-423.2 allows for welder
qualification using any material (to a natl' or internatl' spec, e.g. DIN spec) as long as it meets the
mechanical and chemical requirements of the target P or S No. Therefore, since Section IX
allows for the interchangeability of P and S No's for welder qualification, use of A-36 is
acceptable to qualify Code welders. The fact that the addenda year is not listed for the A-36
material is a moot point. The listing of a specification year and addenda is not a requirement for
Section IX purposes as it is in the referencing book sections. Further, the wide latitude of
acceptable materials used for performance qualification in Section IX confirms that the particular
material does not have as much importance in the qualification as other variables do that confirm
a welder's ability to make a sound weldment.
73. Internal Inspection
Question from a Code stamp holder in regard to internal inspections.
The QC Manager feels after carefully reviewing UG-90, that the requirement stated in UG-90(l),
"performing internal and external inspections and witnessing the hydrostatic or pneumatic tests
(UG-96, UG-97, UG-99,UG-100, and UG-101)", does not infer that every vessel requires an
internal inspection. The QCM believes the words provided in UG-90(c)(1) "some but not all, of
the required inspections and verifications, which are defined in the applicable rules, are
summarized as follows", is where the QCM feels that there is reason to question the need for
internals on each vessel manufactured at his facility.
Response: The words from UG-90(c)(1) are referring to the list of activities (a, b, c, etc.) not
really specific parts of the activities list. UG-90(c)(1)(a) through (n) are also just SOME of the
activities that should be performed. If the AI feels that there should be other things checked then
that is his/her prerogative. Also see UG-97(a), "When conditions permit entry into the vessel, as
complete an examination as possible shall be made before final closure."
Internal inspections are a necessary option for the AI.
Weld penetration, weld size, material condition, nozzle stick through etc. can only be verified by
internal inspection. As the AI, he has the right to perform any inspections he deems necessary
and the option to check inside the vessel is within this scope. Therefore because we recognize
the importance, we have a hold point on the Vessel Traveler for this inspection.
-------------------------------------------------------------------------------74. Application of UCS-68(c) to UG-20(f)
Detail: When UG-20(f) is used for evaluation of impact test for P-No. 1 and Group 1 or 2 materials, the
resulting MDMT without impact test is -20 F. If the PWHT other than that required by the Code is
performed, can this resulting MDMT be further reduced by 30 F to -50 F per UCS-68(c)?
Reply: No, the words of UCS-68(c) say that the 30 F reduction may be given to the minimum
permissible temperature from Figure UCS-66. You have to determine the impact exemption temperature
per UCS to be able to apply UCS-68(c) to P-No. 1 materials.
-------------------------------------------------------------------------------Question: The client has 1" think stainless steel. The client has no WPS qualified for over 3/4". He does
have 2 WPSs - one GTAW and one GMAW qualified to 3/4" with/without backing. The question is can the
2 WPSs be used together to make this weld as long as neither process goes over 3/4"?
Answer: This approach is called piggy backing of welding procedures which is not acceptable to Section
IX,.
The practice violates QW-202.2(a) and QW-451.1.
----------------------------------------------------------------------------------------------------------------------------- ---
75. VIII-1 material marking and "piggy back welding"
Subject: VIII-1, Required Marking of SA-53 Pipe Received in Cut Up Lengths:
Question:
An ASME Certificate Holder buys standard full length (6Meters) of SA 53 pipes
from a supplier with instruction that the pipe be divided (by the
supplier)into the length required and that heat numbers be transferred onto
each piece.
It is their opinion that this meets the requirement of UG-77. Material
certificates are provided in all cases and traceable to the material. The C
of A holder verifies that the heat number are on all the cut pieces during
receiving inspection. The heat number transferred satisfies the term "coded
marking" which is traceable to the MTR. However the customer commented it
should satisfy
the Section 24 of SA 53 for subdividing the pipe for sale and all the
markings required by the material specification be transferred and the
processor's marking or name be included in the marking. Since the C of A
holder is not buying short length of pipe but a full length of 6M is this
required?
Answer:
1. Section VIII-1 UG-94 and UG-93 take precedent over Section II part A when it comes to material
marking and identification. For pipe, the minimum marking required is Specification and Type, Class and
Grade, as applicable. So Paragraph 24 of SA-53 does not control the required marking.
2. Per UG-93(a)(2), Material Test Reports are not required for product form pipe. The pipe need only be
marked with spec/type/class/grade.
3. New paragraph UG-77(c) permits a vessel Manufacturer to receive shapes/parts marked with a coded
marking system from a supplier. How they trace the original required marking to the coded marking must
be described in the Manufacturer's QC program.
The procedure being used satisfies UG-77, UG-93 and UG-94.
------------------------------------------------------------------------------------------------------------------------------76. Calculating the MDMT - VIII Div1
Question: In calculating the MDMT on a vessel with the following conditions:
1) The joint to be calculated is a category B butt weld between a seamless head and a seamless shell.
2) The shell is curve-B and the head is curve-A and the shell is thicker than the minimum head thickness.
3) The shell has a lower allowable stress than the head.
4) The shell will be welded to a straight flange on the head.
In calculating the ratio=trE*/(tn-c):
A) Should the tr to be calculated be based on the longitudinal stress ?
B) Should the lower allowable stress be used in this calculation ?
C) Should the tn to be used be the greater thickness of the two ?
D) Should the reduction temperature be subtracted from the greater of the MDMT shown in Table UCS66 for curve-A or curve-B material ?
Answer:
UCS-66 requires you to evaluate EACH COMPONENT for its impact test exemption temperature versus
its minimum design metal temperature. If you do not have a specified MDMT then the highest impact test
exemption temperature may be used to avoid impact testing all of the components. The governing
thickness for that determination is defined in UCS-66(a)(1) - (3). The governing thickness may or may not
be based on a welded joint.
So the ratio needs to be done for each component if the exemption temp per Figure UCS-66 determined
for each component is warmer than your MDMT.
So, to answer the questions:
A) Should the tr to be calculated be based on the longitudinal stress?
Ans: tr is based whatever you equation you used in Part UG (e.g. usually circ for cylinders)
B) Should the lower allowable stress be used in this calculation?
Ans: component only has one allowable (usually)
C) Should the tn to be used be the greater thickness of the two?
Ans: tn of the component being evaluated
D) Should the reduction temperature be subtracted from the greater of the MDMT shown in Table UCS66 for curve-A or curve-B material?
Ans: reduction temperature is taken from the component.
----------------------------------------------------------------------------------------------------------------------------- --
77. - Material Test Reports - EDI (Electronic Data Interchange)
The General Specifications in ASME Section II Part A, such as SA-6, SA-20, SA-480
have been revised to accept (EDI).
Note: SA-530 was not revised to accept (EDI).
Question: Is EDI acceptable per ASME Section VIII, Division 1, UG-93 (a)(1) where
the supplier is transcribing information? The way I read SA-20 19.7, you still must have
the original manufacturer's test report [the company that melted the steel] in addition to
any subsequent test reports. The acceptance of EDI has not changed anything with regard
to validation of an MTR. The definition of a Material Test Report in Appendix 3,
including the statements concerning transcribing information are still valid when using
EDI to report information.
Answer: Lets look at this from a practical point of view. If a vessel Mfg. purchases plate
material from a supplier, and the MTR reporting all the information required by the
material specification is only on the supplier's letterhead, then one has to assume a) the
material supplier is the material manufacturer who melted and produced the raw material
and finished product; b) the supplier transcribed information from the material
manufacturer. If it is not case a), then there must two pieces of paper [material certs]
supplied with the plate; one from the material manufacturer, one from the material
supplier. To just identify the material manufacturer on the Supplier's cert. does not meet
the code. The test report printed from an EDI from the original material manufacturer
may not contain a logo, etc., but so long as the original manufacturer is listed on this
printout, then it should be accepted.
----------------------------------------------------------------------------------------------------------------------------- --
78. PWHT Question - ASME I
Question: I recently found out strip chart recorders are required for all PWHT. I've had some instances in
the past at various field sites, which is basically owner/user type facilities, where PWHT was done by the
R Stamp Holder by logging the results every 15 minutes. I had approved the procedure. The stress
relieving was done on tube to tube welds, and/or weld buildup, on the secondary superheater, P5b
material tubes, with 5% chromium. Stress relieving was required due to greater than 3% Chromium. The
whole superheater assembly in Boiler #2 has been replaced, so the subject tubes in this boiler are now
gone.
Where is it documented that strip chart records are required? I seen in the QC Manual where it
references calibrated instruments, but it doesn't specifically require strip chart recorders. I try to make
sure they are used now, but occasionally, an emergent job comes up that makes it difficult to go this
route. I'm still not sure where it is written.
Answer: There are numerous requirements in both I and VIII Div 1 that talk about controls for PWHT.
Most people require a written procedure and since they do not want the AI to have to witness the PWHT
then they require a chart. PG-90.1.11 is hard to verify if you do not have a chart. "Duties of AI are to "
verify that all required heat treatments have been performed and are properly documented". I would not
want to try to defend not having a chart to the ASME/NB team leader. This same requirement is in the NB
rules for Commissioned Inspectors par 8.1 (q).
Interpretation: I-81-16
Section I, PW-39 Requirements for PWHT
Subject:
Date Issued: August 6, 1981
File:
BC-80-621
Question (1): If a time-temperature chart is utilized to satisfy the requirements
of PW-39.3, must the chart also reflect the cooldown in a still atmosphere to
800°F?
Reply (1): No.
Question (2): If the answer to the first question is no, how is it demonstrated
that the cooldown to 800°F has been achieved?
Reply (2): The Manufacturer's procedure shall be such that it demonstrates
compliance with PW-39.3.
----------------------------------------------------------------------------------------------------------------------------- -79. VIII Div 1 - UG-93 material marking
Question: (1) A "U" stamp manufacturer purchased SA-106 pipes, they accepted these pipes according
to UG-93(a)(2) without obtaining a Material Test Report or Certificate of Compliance. After a few years,
the manufacturer can not identify the edition of the specification to which the pipes were fabricated. In this
case, can these pipes be used for Code vessel without test and recertification?
Question (2) Can bolts be accepted if the marking requirements of UG-93(a)(2)or(3)are met. According
to SA-193, Para.18, certification is required. Can the vessel manufacturer accept SA-193 bolts if material
certification is not furnished ?
Answer:
1) Yes
2) Yes
Section VIII-1 only requires material certificates for plate material; all other product forms can be accepted
at receiving if marked with specification, grade, type and class. However a lot (maybe even most) U
stamp holders require MTRs for pipe for other reasons such as;
* the final customer may ask for them
* to verify their suppliers quality control identification system works (and pipe is shipped with just heat
numbers and not full marking)
* just to have extra insurance and traceability in case problems occur later or the material remnants are
kept in stock for future use.
----------------------------------------------------------------------------------------------------------------------------- --
80. Boiler Parts and BEP
Question 1: Are pipe spools built to Sect.I req'd to be "S" Part stamped? PG106.8.1 Are they
req'd to be documented on P4 or can they be doc'd on a P4a? PG112.2.4, PG112.2.5, PG109.3
Reply 1: Generally boiler internal piping is considered a part of a completed boiler. As such, it
SHOULD be recorded on a P-4 form and stamped as an S Part. However, there could be
exceptions. The P-4A form is routinely used as form for fabricated piping, regardless if it is
internal or external piping. It really doesn't matter much which form is used, as long as it IS
recorded accurately. But I think the stamping does matter. If someone stamps them as Parts,
they are then indicating they are not taking full design responsibility for the item. If it is NOT
stamped as a part, then it indicates they are responsible for the design.
Question 2: Are small bore parts in PG106.8.2 req'd to be doc'd on P4 or can they be doc'd on
a P4a?
Reply 2:
In this context, they should be reported on a P-4 form. But as mentioned in Reply
1, there could be exceptions. The Code stamping exclusion in PG-106.8.2 is just a subset to the
requirements in PG-106.8. Whatever reporting provisions apply to Parts in PG-106.8, they
would also apply to small parts.
Question 3: May boiler external pipe spools built to B31.1 within the Sect.I jurisdiction, be
stamped "S"Part? PG109.1, PG109.3
Reply 3:
No. BEP is to be stamped with either a PP or S stamp.
Question 4: Re: making flat end closures in headers under a PP stamp. This is not permitted.
PG-109.3 allows a PP stamp holder to fabricate cylindrical parts with a PP stamp if the parts are
welded in accordance with PW-41. PW-41 clearly allows only circumferential welds and not so
clearly allows attachment of connections to piping such as a weld-o-let. But it does not allow the
attachment of a flat plate or end closure similar to that shown in fig PG-31, sketch (g). We
believe that the end closure weld is not a circumferential weld. It is a corner joint. And it is
certainly not a butt weld.
Section I, as you are aware, has several inconsistencies. It is sometimes difficult to discern the
exact rule when there are so many apparent contradictions. Our suggestion is that if you, or you
customer, find areas where a resolution cannot be achieved because of apparent contradictions
then send in an inquiry to the Committee for their interpretation.
81. Section I - Use of SA-36 material
Question: Customer called on the use of SA-36 plate as a flush patch and or plug in a power
boiler. Is this acceptable in Section I construction or NBIC repairs?
Answer: The only permitted usage in Section I is for stays, as referenced in PG-13. The stamp
holder, claims it is acceptable and is listed in Section II Part D. They are correct that it
is listed in II D, but it is only listed as bar stock for Section I.
PG-13 is the only place in Section I that allows the use of SA-36 material and that is only for
stay material.
SA-36 material cannot be used for anything except stays in Power Boilers. Just because a
material is listed in Section II D, that does not mean that it can be used indiscriminately. Section
II D also limits the use of SA-36 in the notes. You are limited to the acceptable use as defined in
the Construction Code.
The ASME Boiler and Pressure Vessel Committee establishes rules to afford reasonably certain
protection of life and property and to provide a margin for deterioration in service so as to give a
reasonably long, safe period of usefulness. It is divided into Sections which determines the rules
for the manufacture of the respective types of vessel. Section II is the Material Specification
Section which specifies material which has been adopted by at least one of the other Sections of
the Code. Section II does not a govern when determining what type of material is permissible
for use in each respective Construction Code. It is only a list of adopted material which is
acceptable in one of the other Codes. Each Section of the Code for construction will govern and
adopt the material which is acceptable for construction to their rules.
See ASME Section I, 2001 edition.
First turn to the 'Forward' on the second page, viii, read the last paragraph on this page. You will
get to a sentence that clearly states what we are discussing. "Not all materials included in the
material specifications in Section II have been adopted for Code use. Usage is limited to those
materials and grades adopted by at least one of the other Sections of the Code for application
under rules of that Section. All materials allowed by these various Sections and used for
construction within the scope of their rules shall be furnished in accordance with material
specifications contained in Section II or referenced in Appendices A of ........" It goes on to say,
"Materials covered by these specifications are acceptable for use in items covered by the Code
Sections only to the degree indicated in the applicable Section.
PG-5, page 5 simply states that all material that is subject to stress due to pressure shall conform
to one of the specifications given in Section II. The last sentence in PG-5, "Specific additional
requirements described in PG-5 through PG-13 shall be met as applicable.
If you read PG-5 through PG-13 it outlines the specific type of material which is acceptable for
use in the construction of boilers. It is broken down into each type of pressure part. You will
clearly see that SA-36 is not an acceptable material for use in Section I.
82. NDE Level III qualification
Question:
The Level III of Company A has left the company, this Level III was qualified as Level III based
on Experience ability ... The QCM is going to subcontract the Level III services to a Company B
that has a U Stamp, the Level III of Company B is a Level III qualified by experience, ability and
continuous satisfactory performance. Is this acceptable?
Response:
Yes, this Level III assignment is acceptable. There are some issues to be verified to ensure that
all is well, however.
Level III examiners are qualified to their employer's Written Practice. The Written Practice must
be developed with SNT-TC-1A as a guide. The Edition of SNT-TC-1A at the time of the Level
III qualification is the key. If this individual was qualified as a Level III under any Edition of
SNT-TC-1A prior to 1992, it is acceptable for him to be qualified under experience. 1992 was
when the requirement for qualification by written examination became effective.
Once qualified, the Level III may be recertified based upon sustained satisfactory performance,
regardless of the Edition of SNT-TC-1A in effect. All versions allow recertification by
experience. Once his qualifications lapse. he comes under the requirements for initial
certification again. It is important that the Manufacturer appoint the Level III to act as their Level
III by letter, and receive a letter accepting the appointment from the appointed individual. These
should be kept on file by the Manufacturer. Copies of the Level III qualification records and
current eye exams must be kept on file by the Manufacturer. The Written Practice for the
subcontracted organization must be compliant with the current Code accepted Edition of SNTTC-1A, which is the 1996 Edition with 1998 Addenda. It should be kept on file as well. Finally,
the written procedure to be applied when performing radiography should be compliant with the
current Edition and Addenda of Section V, Article 2, and also kept on file by the Manufacturer.
83. VIII Div 1 - UCS-66 - "GOVERNING" thickness for establishing MDMT?
Question: Manufacturer is intending to weld a heavy series LWN flange (SA105 – Curve B)
into a shell (SA516-70 Curve D). The flange does not qualify for the UCS66(C)(4) B16.5, –20 F
impact exemption due to its outside diameter. The flange neck is 3.875” thk and the shell is 2.0”
thk. UCS66(a)(1)(b) states that the thinner of the 2 components should be used as the governing
thickness. Does this mean that this lesser thickness, of 2”, should be applied to the Curve B
material, which is actually 3.875’, or should it be applied to the Curve D material?
Answer: Yes, you have interpreted the rules of UCS-66(a) correctly. When you go into Figure
UCS-66, you use the so-called "GOVERNING" thickness for each material on either side of the
joint. Therefore, for your example since UCS-66(a) says to use the thinner of the two
components in a corner joint, the governing thickness would be 2". You would then go to Curve
B at 2" to assign an MDMT for the flange, and to Curve D at 2" to assign an MDMT for the
shell.
This part of the process is described in Fig UCS-66.2, Step 2 and Note (5).
These 2 values of "raw" MDMT could then each be further modified by UCS-66(b) using the
coincident ratio defined in Fig. UCS-66.1 when the ratio is less than one.
84. - Rods and Bars used as nozzles in VIII Div 1 vessels?
Question: My AI says I cannot machine rod or bar to use as nozzles in my Section VIII Div 1
vessel! Why not?
Answer: Your AI is correct, however there is a Code Cases (2148) that may allow it with some
restrictions. If you look at UG-14 in VIII Div1 you will note the restrictions on the use of rod
and bar and you will see that nozzles are not mentioned as one of the permitted applications.
The purpose of the "rod and bar" Code Case is the perceived anisotropic properties (the worst
case being laminations) of these product forms - that the properties are not the same in all 3
directions. Therefore, if a rod or bar is loaded other than along its axis, it may experience a
premature failure. This case is exemplified by a rod that is bored out and exposed to internal
pressure such that the hoop stress is not oriented along the axis of the bar.
Side note: Other rod and bar Code Cases of interest (2155 - heads, 2156 shells)
85. VIII Div 1 vessel hydrostatically tested in the vertical position
Background: An ASME VIII Div 1 fabricator is building small "UM" heat exchangers in which
the tube side is made up of a coiled tube that penetrated the shell side shell wall with an inlet and
outlet coupling. This coiled tube is less than 6 in. in diameter and contains water at 150 psi at
150 degrees Fahrenheit.
Question:
What about note 39 of Appendix W? This note states that if a vessel is hydrostatic tested in a
vertical position this must be stated in the remarks section of the Data Report. The customer was
asking why the Code required this? What is the purpose was for remarking on the Data Report if
a vessel is hydrostatically tested in the vertical position? . What is the rationale behind this? If
one were constructing a 200 ft. tower this might be information that would be of value to the end
user. But the situation with this customer is that he builds a small vessel only 13 in. tall that
does get tested in the vertical position. It does seem bizarre to have to state on the Data Report
that such a small vessel was tested in the vertical position!
Answer:
You cite a perfect example of when a generic rule makes no practical sense at all, a situation
when the nonmandatory generic guideline obviously has no structural significance and should,
with the AI's agreement, be ignored. However, there are cases when the exception to the normal
horizontal-position shop hydrotest is practical and is desirable for structural reasons, and of
course for field assembly/construction situations it is necessary. In those situations, the fact that a
vertical hydrotest test was conducted can be very useful information, information that could
prevent a dumb mistake during future( post construction ) situations. Accordingly, I think the
guideline should stay. Besides, it probably prevents us from having to develop a guideline as to
when the effects of a hydrotest head should be, and need not be, considered, a virtually
impossible task. For applications involving very tall vessels it is important for the end user to
know whether not such a vessel is tested in the vertical position. This is the problem with
writing a generic rule to cover everything from pressure cookers to 200' long towers.
86. VIII Div 1 vessel Code boundary
Question: A customer called looking for information regarding whether not the seal weld used to
attach a threaded plug to a coupling in a pressure vessel would be considered a Code weld?
Answer: The ASME Section VIII, Division 1 Code defines the pressure vessel boundary in the
Introduction chapter, paragraph U-1(e). The purpose of this paragraph is to define the Code
boundary for the vessel when it is stamped and certified by the Manufacturer. The general rules
of thumb are as follows:

Nozzles, couplings, necks, etc. and their attachment welds to the vessel are always
considered part of the Code Vessel.

When a nozzle or a coupling is connected to piping, the Code boundary ends at the weld
prep of the nozzles or coupling. The weld is not considered part of the Code stamped
vessel unless the vessel manufacturer wanted it to be. He would do this by indicating on
his drawings and on the manufacturer's data report where he intended to end the Vessel
boundary.

In the case of a threaded plug being installed into a coupling and then seal welded, if this
is done during the fabrication of the pressure vessel and prior to certification, then the
threaded plug and weld are considered part of the Coded vessel. However, if the vessel is
stamped and certified without the threaded plug installed, and this plug and seal weld are
installed in the field, then the plug and seal weld come under the jurisdiction of the
applicable piping Code such as B31.3.

In either case the seal weld would be considered a Code weld in as much as the weld
procedure and welder should be qualified to Section IX since both Section VIII and the
piping Codes use Section IX to control all welding. The one difference is that if the
threaded plug and seal weld were originally considered part of the pressure vessel when it
was first constructed, then the activity of removing and reinstalling a welded plug could
be considered a repair under the NBIC code and thus may involve the services of an NB
Commisoned Inspector.
To summarize all of the above, is the threaded plug seal weld a Code weld? Maybe. Should the
seal welding of the threaded plug to the coupling be carried out with a Section IX qualified
procedure and welder? Yes.
87. VIII Div 1 UW-11(a)(5)(b)
Background: ASME Section VIII Div 1 "U" stamp holder and their Authorized Inspector
disagree on the requirements for spot examination of a Section VIII-1 vessel. The vessel has a 40
inch diameter, single wall, seamless head and 1/2 inch wall thickness for the shell and head.
Total length of Cat A and B welds ~29 ft. All welding performed by one welder.
Question: What is the number of RT spot examinations in order to use: E=1 for the head
thickness calculation; E=.85 for the shell (hoop stress) calculation using type 1 joint?
Answer: A minimum of two 6-inch spot examination would be required: 1 for the quality factor
UW-11(a)(5)(b) and 1 for the weld increment UW-11(b).
Another issue is placement of the spot examination. The Code rules [UW-52(b)(3)] is very clear
that the AI has this prerogative, unless the AI waived his prerogative, only then may the
manufacturer designate the area to be examined.
88. Section I, PG-99, Application of Insulation Prior to Hydrostatic Test
AI is having disagreement (difference of opinion) with a boiler "A" assembler about the
quantity of insulation that is present during hydrostatic test of a boiler. ASME has issued past
interpretations, with the most recent as follows:
"Question: May portions of welded power boilers that do not contain longitudinal welded joints
made with the addition of filler metal be covered with insulation or refractory prior to the
hydrostatic test required by PG-99?
Reply: Yes; however, the Authorized Inspector may require the hydrostatic test pressure to be
maintained at the maximum allowable working pressure for an extended period of time,
sufficient to assure there is no indication of leakage. The Authorized Inspector may also require
the removal of insulation for cause."
Note: The reason for specifying the longitudinal seams is that they are usually the higher stresses
seams and more likely to fail. It is ultimately up to that AI, but if the "A" stamp holder insists on
testing with insulation present on circumferential, nozzle, etc. seams, then a much longer hold
time should be imposed, which is within the AI's right. Make it real long so you will definitely
see a pressure drop if there is a leak. You should see all (or as many as possible) seams if you
are the AI signing the Manufacturer’s Data Report.
89. VIII Div 1 purpose of final pressure test
Question: Our heat exchangers are built to ASME Section VIII, Division 1 Code
requirements and hydrostatically tested to the requirements of UG-99. UG-99
does not state a time to hold the pressure vessel at the test pressure to
check for leaks. Our standard hydrostatic test procedure states that we
will hold the heat exchangers at the required test pressure for 15 minutes
per test to check for any leaks. If a test greater than 15 minutes is
required then after the initial 15 minute period at 1.3 test pressure ratio
we drop the pressure to the maximum allowable working pressure for the
remainder of the test period. Our position is that the 1.3 test pressure ratio is a deformation
check and should not be held for extended periods of time. Can you describe
the intention of UG-99 as far as the time that is required for the pressure
test and the acceptance of our test procedure as described above.
Answer:
The purpose of the final pressure test [hydrostatic or pneumatic] is threefold:
1. It is first and foremost a safety test. It is the final opportunity to verify that there were no
gross errors in design or construction of the pressure vessel.
Although VIII-1 does not specify the length of time that the vessel must be held at the test
pressure, it is common that the vessel be maintained at the full test pressure for a least 10
minutes in order to allow the material to reach an equilibrium state, and to be able to determine if
there is going to be any gross deformation.
2. It is a leak test for the purpose of verifying no leakage through any pressure boundary welds
or any permanent gasketed joints. This inspection takes place with the vessel at a lower pressure
equal to the test pressure divided by the pressure test factor [1.3 for hydrostatic test, 1.1 for
pneumatic.
3. Finally by subjecting the vessel to a pressure equal to 1.3 times the MAWP, a small amount of
stress relief occurs as well as some crack blunting. There have been numerous studies conducted
which demonstrated the quantifiable benefits from subjecting a vessel to a pressure higher than
its original design pressure for a short period time.
In conclusion, for the purposes of conducting a final pressure test, holding the vessel at its test
pressure for a period longer than 10 to 15 minutes adds no further value to the process. But at
the same time considering the large design margin built into VIII-1, holding a vessel at the test
pressure for a period of time longer than 10 to 15 minutes should have no detrimental effect for
most pressure vessels.
90. VIII Div 1 impact test requirements for UG-11 manway assemblies.
Question is in reference to a prefabricated manhole ring for an elliptical manhole. This ring is
furnished to the vessel manufacturer with a cover as a completed item, per UG-11, for
installation in a Section VIII, Division 1 vessel. The standard ring is formed from SA-675 Gr 70
3/4" x 4" bar material and the ring is welded and stress relieved prior to machining.
This material appears to be a curve-A material and would require impact testing, based on the
3/4" thickness, for the standard -20 deg.F MDMT as a component.
The ring would be welded to a 1/2" plate SA-516 Gr 70 shell and the shell would govern under
UCS-66(a)(1)(b) for impact testing exemption.
1) Would the SA-675 bar require impact testing?
2) Should this ring be fabricated from SA-516 Gr 70 and be exempted under UG-20(f)?
Answer:
You said that this is a prefabricated manway ring under UG-11. So, per Figure UCS-66, Note
(b)(4) it is Curve B. Also per UG-11 the parts would be supplied with pressure-temperature
ratings [UG-11(c)(2) and UG-11(a)(1)] which probably say that it is good for -20F.
The manufacturer of the rings most likely takes the value from Figure UCS-66 and then reduces
it by 30F per UCS-68(c) because their PWHT is not required by Code but they do it anyway.
If you manufactured the rings yourself out of SA-675, they would have to be impact tested.
91. B31 Socket Weld Fitting Fit-Up Gap
Question : What is the rationale for mandating that a 1/16th inch gap be maintained when
welding socket welded fittings to pipe per B31?
Answer: The purpose of the gap between the end of the pipe and the bottom of the socket weld
fitting during fit-up is to ensure that any differential thermal expansion between the pipe and
fitting will not place additional stress on the fillet weld. See following B31 interpretations on this
subject, all of which state that the gap must exist during fit-up, but it need not be measured after
welding.
Interpretation: (B31.1) 19-5
B31.1, 127.3.3(A), Gap Requirements for Socket Welds
Subject:
Date Issued: April 5, 1991
B31-91-002
File:
Question (1): Does Para. 127.3.3(A) require that the approximately 1/16 in. gap
required during fitup exist after welding is completed?
Reply (1): No.
Question (2): Does ASME B31.1 require an examination, radiographic or otherwise, to
verify that the fitup gap required by Para. 127.3..3(A) exists in the completed weld?
Reply (2): No.
Interpretation: (B31.3) 10-19
ANSI/ASME B31.3-1984 Edition, Para. 327.4.2, Fillet and Socket Welds
Subject:
Date Issued: December 2, 1991
B31-91-039
File:
Question: Are socket weld joints with intimate contact before welding (i.e., zero gap)
between the end of the pipe and the bottom of the socket weld fitting prohibited by the
Code?
Reply: Yes.
Interpretation: (B31.3) 16-06
ASME B31.3-1996 Edition, Para. 328.5.2, Welding Requirements - Fillet and
Subject:
Date Issued:
Socket Welds
May 20, 1997
File:
B31-96-058B
Question: In accordance with ASME B31.3-1996 Edition, para. 328.5.2 and Fig.
328.5.2c, what is the minimum gap acceptable in a socket-welded joint after welding?
Reply: The 1/16 in. approximate gap shown in Fig. 328.5.2c is "before welding." The
Code does not provide a gap dimension after welding.
92. Question: Where in the ASME Code are international materials listed?
Answer: International materials are treated essentially no different than ASTM materials. (see
Forward to the ASME Construction and Reference Codes ...." Revisions to material
specifications are originated by the American Society for Testing and Materials (ASTM), and
other recognized national or international organizations and are usually adopted by ASME."
The materials that ASME has accepted thus far are listed in:
Section II, Part A on pages xxxvii and 1473-1475, Section II,
Section II Part D on page 6 (lines 7 & 25), page 10 (lines 35 & 36), and page 14 (line 12 &13),
Section I PG-6 (page 6, SA/EN-10028-2),
Section IV Table HF-300.1 Note (19),
Section VIII, Division 1 UCS-6(b) page 177 (SA/CSA-G40.21 38W) and Table UCS-23 page
303 (SA/EN 10028-2, 3 and SA/CSA-G40.21 38W) ,
and Section IX QW/QB-422 p. 110.
93. VIII Div 1, UG-10 and identical ASTM material
Question: An ASME VIII Div 1 "U" stamp holder wants to know if they have to issue a
nonconformity (NCR) referencing "UG-10" for materials that are coming in to their shop
certified as "A" (ASTM) and not "SA" (ASME), which was how they were ordered?
Answer: The QC manual should be followed closely as there may or may not be an NCR
required depending upon the how the Manual is written. An NCR would be one way to
document the situation and corrective action taken. For "A" verses "SA" materials, the word
"identical" is the key. UG-4 states that the "SA" and "SB" material for Section VIII, Div. 1
construction are listed in Section II, Part A or B. The Foreword and Appendix A of Section II,
Part A pretty much says that material produced under an ASTM Specification may be used in
lieu of the corresponding ASME Specification as listed in Appendix A. This means IF the
ASTM material specification that is listed on the MTR is identical with the one in Appendix A
(specification year needs to be listed on the MTR to verify this) then there is no need for
"recertification" under UG-10. Recertification really means something was done to verify the
acceptance of the material - besides just scribbling on the MTR or marking an "S" in front of the
"A" on the material.
An additional note: the exceptions that ASME has taken occur in more than 95% of the
materials. Looking at Appendix A they have taken exception to something in a lot of
specifications - mostly corrections that ASTM hasn't gotten around to yet.
94: VIII Div 1 - UW-16(c) - Nozzle attachment welds, full penetration?
Question:
According to UW-16(c), when complete joint penetration cannot be verified by visual inspection
or other means permitted in this Division, backing strips or equivalent shall be used with full
penetration welds deposited from one side. Besides visual inspection and RT, are there other
means permitted by Code to verify full penetration? When it's not possible to verify complete
joint penetration and if GTAW welding is used for root pass of the joint, does it meet Code
requirements, and can the welding groove be made by gas cutting? If neither use of backing strip
or GTAW is used for root passes of the joints, can we accept it through proper fit-up inspection?
Answer:
Besides visual and RT you may be able to use UT. Although, due to the configuration (corner
joint), it is not clear how useful RT and UT will be. There is really not any other method of
verifying complete penetration of this joint. Using a specific welding technique cannot
guarantee complete penetration. Visual inspection, either direct or indirect (e.g. mirror,
boroscope, fiber optics, etc), is the best method of examination to insure complete penetration.
One main reason for the verification of the full penetration joint is that the Code does not want a
crack left on the inside of the vessel. This is a high stress concentration area and an area where
corrosion will begin.
There is nothing in the Code that tells you how to make the weld groove. UW-9(b) states that
"the dimension and shape of the edges shall be such as to permit complete fusion and complete
penetration." UW-31(a) states that "when plates are shaped by oxygen or arc cutting, the edges
to be welded shall be uniform and smooth and shall be freed of all loose scale and slag
accumulations before welding." So the Code does not specify the method of cutting but does
require that the edges be machined so that they provide a clean surface for the welding.
95: Titanium not reported as an unspecified element as required by SA-20 par. 7.1.1.1
Background: The 2002 Addenda to ASME Section II A of SA-20 SPECIFICATION FOR
GENERAL REQUIREMENTS FOR STEEL PLATES FOR PRESSURE VESSELS (referenced
by numerous plate material specifications), Table 1 requires Titanium to be reported on the
Material Test Report.
Question: How can material be accepted if Titanium is not reported as an unspecified element
on the MTR as required by SA-20 par. 7.1.1.1?
Answer: For right now, the only user options are Appendix A of ASME II A and Code Case
2053 (For Materials in Inventory Sections I, IV, and VIII Div 1 and 2). Code Case 2053 must be
noted on the Manufacturer's Data Report. CC 2053 expires 11-28-03.
96: ASME Section I - difference between tube and pipe
Question: May a SA-335 Seamless Ferritic Alloy Steel Pipe for High Temperature Service be used for
boiler tube? This material is listed in PG-9.1.
Answer: There is nothing in Section I that would prohibit the use of a pipe specification material in a
"tubing" application. In most cases, the only real difference (other than the title of the specification)
between "pipe" and "tube" material is the tolerance's that are listed in the respective specification and PG9.
As general boiler industry practice, if the primary application for the material is heat transfer then it is
usually considered to be "tubing" and the equation from PG-27.2.1 is used to calculate the thickness. If
the primary purpose is fluid conveyance with relatively little or no heat transfer function then it is "piping"
and the equation in PG-27.2.2 is used. These paragraphs make no mention of an appropriate material to
be used. In fact, both sets of equations use the same variable, t, for the minimum required thickness.
I've attached an Interpretation that discusses the definition of "piping" and "tubing" that may help. It is
important to note that "pipe" and "tube" are material product forms and "piping" and "tubing" are
applications or functions. note: see below interpretation.
Interpretation: I-86-25
Subject:
Section I, PG-27.2, Wall Thickness of Pipe and Tube
Date Issued: June 23, 1986
File:
BC81-713, BC83-289, BC83-669, BC84-230
Question: Under what circumstances do the equations under PG-27.2.1 (for tubing)
and PG--27.2.2 (for piping) apply?
Reply: The formulas in ASME Section I, PG-27.2.1, for tubing, are intended primarily
for applications such as boiler tubes, superheater and reheater tubes, or economizer
tubes in which groups of such tubular elements are arranged within some enclosure
for the purpose of transferring heat to or from the fluid within the tubes. For this heat
transfer function, the tubular elements ordinarily do not need fittings or valves.
When the function to be performed is mainly the conveying of a pressurized fluid from
one location to another, with little or no intentional heat transfer, the formulas in PG27.2.2 should be used. The elements commonly used for this purpose are called
piping. The standard piping sizes are available with matching sizes of fittings (tees,
elbows, etc.) and valves to facilitate the installation of piping systems to direct and
control the flow.
97: UG-99 - Hydrostatic test pressure - VIII Div 1
Question from a stamp holder about the difference between UG-99(b) and UG-99(c). The customer has
asked for a test based upon UG-99(c). What is the difference?
According to UG-99 of ASME SEC.VIII, Hydro test press(Ph) is calculated as the follows;
1. HYDRO. TEST PRESSURE(which at every point in vessel for internal pressure)
P(hydro) = 1.3 x M.A.W.P(or D.P) x Ratio
St : Stress Value At Test Temperature per each material
Sd : Stress Value At Design Temperature per each material
Ratio : St / Sd
2. The User spec. is "the test pressure shall be at least 50% higher than design pressure."
P(hydro) = 1.5 x D.P x Ratio or P(hydro) = 1.5 x D.P
Answer:
We will assume that you intend to Code stamp the vessel, and therefore the answer is based on meeting
all of the Code requirements.
1. The minimum hydrostatic test pressure is given in paragraph UG-99(b), and is equal to 1.3 x MAWP x
STratio [STratio is the lowest ratio, considering all of the materials used in the construction of the
pressure vessel, of the stress value S for the test temperature on the vessel to the stress value S for the
design temperature.] The MAWP is the pressure listed on the nameplate and is equal to or greater than
the design pressure. Any additional pressure due to the static head of water that exists during the test is
not included in the determination of the test pressure.
2. Paragraph UG-99(c) provides an option to conduct a hydrostatic test based on a calculated pressure
which considers the vessel in new and cold condition. In this case, the test pressure is normally higher
than the value provided in paragraph UG-99(b). Conducting a hydrostatic test based on calculated test
pressure requires an agreement between the user and the manufacture, and the AI has the right to
review the calculations used to determine this calculated test pressure.
3. Per UG-99(d) there is no upper limit on test pressure and Section VIII, Division 1. However the
Inspector has the right to reject the vessel if he observes any permanent distortion of the vessel following
the test.
4. If you choose to conduct the pressure test per your customer's specification, you should perform the
calculations required by UG-99(c) and determine the Code " calculated test pressure " based on new and
cold conditions. If the test pressure required by the customer's specification (1.5 x design pressure) is
greater than the calculated test pressure given by UG-99(c), then you should calculate the actual stress in
the pressure vessel during the test and compare this to the yield strength of the material, to ensure that
there will be no permanent distortion of the vessel.
98: Section I power boiler hydrostatic test water temperature
Question: PG-99, ASME Section I requires that pressure tests required be conducted using water
at a temperature not less than 70oF.
We use hot water above 70oF but we don't keep the temperature above 70oF during pressure
tests because of ambient temperature.
1) May pressure tests required by PG-99 be conducted using water at a temperature less than
70oF during pressure tests ,if we use hot water above 70oF ?
2) Why does Code require using water at a temperature not less than 70oF?
Answer:
PG-99 is clear that the water temperature shall be no less than ambient temperature, and in no
case less than 70 degrees F. Interpretation I-95-27 (included below) supports the existing Code
words. There are a couple of reasons for the minimum temperature. It is believed that the 70 oF
would keep the metal temperature above the range where brittle fracture could occur since
Section I does not have the same minimum design metal temperature as those in that Section
VIII. A second possible reason is that using a temperature below ambient or 70oF (the warmer
of the two) could result in condensation on the metallic surfaces which could conceal small
leaks. It is often common practice when boilers are installed on-site in cold regions (or in cold
shops) that a secondary boiler or heat exchanger is used to provide the boiler with warm water
for hydrostatic testing purposes.
Interpretation
I-95-27
Subject:
Date Issued:
Section I, 1992 Edition, PG-99, Pressure Testing of Completed
Boiler Using Water at Ambient Temperature
April 16, 1996
File:
BC95-499
Question: May pressure tests required by PG-99 be conducted using water at a
temperature less than 70oF?
Reply: No.
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