ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
Basics of ASME Section VIII Division 1
Pressure Vessels
Structure & Usage of
The Code Book
For
BEGINNERS
This guide is exclusively prepared for training purpose. Relevant specifications, codes &
special requirements of specific project are to be referred for more detailed information
during construction. Examples provided are only for the purpose of illustration.
The objective is to be familiar with Basic / Fundamental concepts of the code.
N.Rajasekaran (RAJ) +971-50-6682960
Page 1 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
Need
Early Boiler
Room Heater
Result
Explosions
Death & Injuries
Corrective
action
Committee
ASME sponsor
ASME Code
Definitions:
Specify
To State or Describe
clearly and exactly.
Pressure
Vessel
U-1(a)(2) For the scope of this
Division,
pressure
vessels
are
containers for the containment of
pressure,
either
internal
or
external. This pressure may be
obtained from an external source, or
by the application of heat from a
direct or indirect source, or any
combination thereof.
Construction
An all inclusive term comprising
materials,
design,
fabrication,
examination,
inspection,
testing,
certification and pressure relief.
Mandatory
describes something which must be
done, or which is demanded by law
Page 2 of 27
something
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
ASME
American Society of Mechanical Engineers
Code Books: New issuance every 3 Years
Edition 2007:
Addenda 2008:
Addenda 2009:
Edition 2010:
White pages (loose-leaf format)
Pink Pages (replacement)
Blue Pages (replacement)
White pages ……..and so on
Contents:
(1) Mandatory requirements,
(2) Specific prohibitions
(2) Non-mandatory guidance
Interpretations:
ASME’s written replies to inquiries concerning
interpretation of technical aspects of the Code.
Issued semi annually (July and Dec) as
separate document.
CODE CASES:
Proposed additions and revisions to the Code.
(to clarify the intent of existing requirements)
or
To provide rules not covered by existing Code.
Page 3 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
.The
ASME Code Books
Sec I
Power Boilers
Part A
Materials : Ferrous
Ref
Part B
Materials : Non Ferrous
Ref
Part C
Materials : Filler & Electrodes
Ref
Part D
Material Properties (US ) or (Metric)
Ref
Sec II
Sec III
Rules for Construction of Nuclear Facility
Components
Sec IV
Heating Boilers
Sec V
Nondestructive Examination
Sec VI
Care and Operation of Heating Boilers
Sec VII
Care of Power Boilers
Sec VIII
Div 1
Pressure Vessels
Div 2
Alternative Rules - Pressure Vessels
Div 3
Alternative Rules – High Pressure Vessels
Sec IX
Welding and Brazing Qualifications
Sec X
Fiber-Reinforced Plastic Pressure Vessels
Sec XI
In-service Inspection of Nuclear Power Plant
Components
Sec XII
Construction and Continued Service of
Transport Tanks
Page 4 of 27
Ref
Ref
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
The Sec VIII Div 1 Code Book
Foreword
Statement of Policy
Personnel
Summary of Changes
Introduction - U
Sub section C
Classes of
Materials
Sub section B
Method of
Fabrication
Sub section A
General
Requirements
Mandatory Appendix – Arabic Numerals
Non Mandatory Appendix – Alphabets
S.I Units
Index
Total Pages 40+675 = 715 (incl. front back cover)
Edition 2007
Page 5 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
Unfired Vessel:
U
General :
UG
Welding :
UW
Carbon Steel:
UCS
……..and so on
Title
0mm
SCOPE
U-1
4 mm
U-1(a)
7 mm
U-1(a)(1)
12 mm
(a)
15 mm
(1)
Numeric-(Alphabetic)-(Numeric)
(Alphabetic)
(Numeric)
The Code does not address all aspects of these activities and those aspects which
are not specifically addressed should not be considered prohibited.
The Code is not a handbook and cannot replace education, experience, and the use of
engineering judgment. The phrase engineering judgment refers to technical
judgments made by knowledgeable designers experienced in the application of
the Code.
Engineering judgments must be consistent with Code philosophy and such
judgments must never be used to overrule mandatory requirements or specific
prohibitions of the Code.
The Code does not fully address tolerances. When dimensions, sizes, or other
parameters are not specified with tolerances, the values of these parameters are
considered nominal and allowable tolerances or local variances may be considered
acceptable when based on engineering judgment and standard practices as determined
by the designer.
Page 6 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
Vessel Scope by application: U-1(c)(2)
Vessels not included
Listed U-1(c)(2) : (a) Thro (j)
Pressure below 3000 psi (in General)
Vessel scope by geometry: U-1(e)
First girth weld (Circumferential joint)-by welding
First threaded joint – for screwed connection
Face of First Flange – by bolting
Including covers – for Manholes
Code accepted Referenced editions : U-3
Units of measurement – U-4 (Code case 2523 )
Page 7 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
Sub Section A
PART UG :
General Requirements
(Common for Sub section B and C)
Materials
UG 4 - UG 15
Design
Openings
Stay
Ligament
Fabrication
Inspection & Tests
Marking & Reports
Pr Relief
Figures
Tables
Page 8 of 27
Fill Here !
Excercise
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
70,000 PSI
7 0pKl S
Exa(m
eI:)
UTS
UTS
SMYS
SA 516 Grade 70 (MSeAtric516M Grade 485)
485 MPa
(70 KSI)
UTS
= 70,000 PSI
= 38,000 PSI
S (allowable stress used in design for Temperature upto 500°F) = 20,000 PSI
[Page 16 of Sec II Part D – U.S Customary]
F.S
= 38 / 20
= 1.9
U-4: UNITS OF MEASUREMENT
For any single equation, all variables shall be expressed in a single system of units.
When separate equations are provided for U.S. Customary and SI units, those equations
must be executed using variables in the units associated with the specific equation.
70,000 PSI
485 - 482.633
2.367 MPa
= 482.633 MPa
= 2.367
= 343 PSI !!!
1 MPa = 145.0377 PSI
Therefore
Do not mix two system of units in calculations.
Sec II Part D ( The stress values) is issued in two versions
U.S Customary & Matric/S.I
Page 9 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
Basic approach of design



σa, sometimes called the longitudinal stress
tangential stress, σt, also referred to as the hoop or circumferential stress
radial stress, σr . . . all of which are taken to be positive tensile.
axial stress,
Cylinders are usually considered to be either thick - in which stress
concentration due to relative curvature is significant - or thin in which
stress concentration is negligible. Other differences are :
Limiting proportions (appr ox)
Analytic treatment
Statically determinate
Stress state
Stress - radial, σ r
- tangential, σt
- axial, σa
Thin
Thick
D/t
> 20
i
Di/t < 25
simple approximation
yes
membrane - ie.
biaxial
accurate
no
zero
uniform
uniform
triaxial
varies with radius
varies with radius
uniform
The dividing line between thin and thick - is not hard and fast.
Page 10 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
σc
=
p Di / 2 t (Circumferential Hoop stress acting on Long seam weld )
σl
=
p Di / 4 t (Longitudinal stress acting on cir seam weld)
Conclusion:
Cir seam weld is TWICE stronger than Long seam weld when subjected to pressure.
Therefore
Long seams are Category A : Cir seams are Category B
Basic Formula : σc = p D / 2 t; therefore t =
i
Code Formula:
pressure
p Ri /
σc
t = (p R )/ (SE-0.6p) : σc = S = allowable stress
i
= 250 PSI (p)
Radius (int) = 32 inch
Stress allowable = 20,000 PSI (SA 516 Gr 70)
Basic Formula
Code Formula
t= 0.4” (10.16 mm)
t= 0.403” (10.24 mm) if FULL RT (E=1.0)
t= 0.475” (12.06 mm) if SPOT RT (E=0.85)
t= 0.578” (14.67 mm) if NO RT (E=0.7)
UG-32:
FORMED HEADS, AND SECTIONS, PRESSURE ON CONCAVE SIDE
All formed heads concave to pressure and intended for butt welded attachment
need not have an integral skirt when the thickness of the head is equal to or less
than the thickness of the shell. When a skirt is provided, its thickness shall be at
least that required for a seamless shell of the same inside diameter.
Flat spot on head max allowable diameter
UG-32 (o)  UG-34 Formula (1), C=0.25
Page 11 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
UG-37:
REINFORCEMENT REQUIRED FOR OPENINGS IN SHELLS AND FORMED
HEADS
Page 12 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
UG-80:
PERMISSIBLE OUT-OF-ROUNDNESS OF CYLINDRICAL, CONICAL,
AND SPHERICAL SHELLS
(Internal pressure)
UG-93:
INSPECTION OF MATERIALS
(a) Except as otherwise provided in UG-4(b), UG-10, UG-11, or UG-15,
requirements for acceptance of materials furnished by the material
manufacturer or material supplier in complete compliance with a material
specification of Section II shall be as follows.
(1) For plates,2 the vessel Manufacturer shall obtain the material
test report or certificate of compliance as provided for in the
material specification and the Inspector shall examine the Material
Test Report or certificate of compliance and shall determine that it
represents the material and meets the requirements of the
material specification.
(2) For all other product forms, the material shall be accepted as
complying with the material specification if the material
specification provides for the marking of each piece with the
specification designation, including the grade, type, and class if
applicable, and each piece is so marked.
UG-99:
STANDARD HYDROSTATIC TEST
(g) Following the application of the hydrostatic test pressure, an
inspection shall be made of all joints and connections. This
inspection shall be made at a pressure not less than the test
pressure divided by 1.3. Except for leakage that might occur at
temporary test closures for those openings intended for welded
connections, leakage is not allowed at the time of the required
Page 13 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
visual inspection. Leakage from temporary seals shall be directed
away so as to avoid masking leaks from other joints.
Static head of water : 0.433 psi for every feet of height.
UG-102:
TEST GAGES
(b)
UG-116:
REQUIRED MARKING
RT 1”
“
RT 2”
“
RT 3”
“
RT 4”
“
Dial indicating pressure gages used in testing shall be
graduated over a range of about double the intended
maximum test pressure, but in no case shall the range be less
than 11⁄2 nor more than 4 times that pressure. Digital
reading pressure gages having a wider range of pressure may
be used provided the readings give the same or greater
degree of accuracy as obtained with dial pressure gages.
when all pressure-retaining butt welds, other than Category B and C butt
welds associated with nozzles and communicating chambers that neither
exceed NPS 10 (DN 250) nor 11⁄8 in. (29 mm) wall thickness [except as
required by UHT-57(a)], satisfy the full radiography requirements of UW11(a) for their full length; full radiography of the above exempted Category
B and C butt welds, if performed, may be recorded on the Manufacturer’s
Data Report; or
when the complete vessel satisfies the requirements of UW-11(a)(5) and
when the spot radiography requirements of UW-11(a)(5)(b) have been
applied; or
when the complete vessel satisfies the spot radiography requirements of
UW-11(b); or
when only part of the complete vessel has satisfied the radiographic
requirements of UW-11(a) or where none of the markings “RT 1,” “RT 2,” or
“RT 3” are applicable.
Page 14 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
Sub Section B
PART UW :
Welding Requirements
UW-2:
SERVICE RESTRICTIONS
(a)
When vessels are to contain lethal1 substances, either liquid
or gaseous, all butt welded joints shall be fully
radiographed, except…….
UW-3:
WELDED JOINT CATEGORY
UW-11:
RADIOGRAPHIC AND ULTRASONIC EXAMINATION
(a)
(b)
(c)
UW-12:
Full Radiography
Spot Radiography.
No Radiography
JOINT EFFICIENCIES
Table UW-12
Page 15 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
UW-33:
ALIGNMENT TOLERANCE
Joint Categories
UW-51:
Thickness (mm)
A
B, C, & D
Up to 13, incl.
¼t
¼t
Over 13 to 19, incl.
3 mm
¼t
Over 19 to 38, incl.
3 mm
5 mm
Over 38 to 51, incl.
3 mm
⅛t
Over 51
Lesser of 1⁄16t or 10mm
Lesser of ⅛ t or 19 mm
RADIOGRAPHIC EXAMINATION OF WELDED JOINTS
(1)
any indication characterized as a crack or zone of incomplete fusion or
penetration;
(2)
any other elongated indication on the radiograph which has length greater
than:
(a) 1⁄4 in. (6 mm) for t up to 3⁄4 in. (19 mm)
(b) 1⁄3t for t from 3⁄4 in. (19 mm) to 21⁄4 in. (57 mm)
(c) 3⁄4 in. (19 mm) for t over 21⁄4 in. (57 mm)
where
t = the thickness of the weld excluding any allowable reinforcement. For
a butt weld joining two members having different thicknesses at the
weld, t is the thinner of these two thicknesses. If a full penetration
weld includes a fillet weld, the thickness of the throat of the fillet
shall be included in t.
(3)
any group of aligned indications that have an aggregate length greater
than t in a length of 12t, except when the distance between the successive
imperfections exceeds 6L where L is the length of the longest imperfection
in the group;
(4)
rounded indications in excess of that specified by the acceptance
standards given in Appendix 4.
Page 16 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
UW-52:
SPOT EXAMINATION OF WELDED JOINTS
1 spot in 50 feet RT
(1) any indication characterized as a crack or zone of incomplete fusion or
penetration;
(2) Elongated > 2/3 t (thinner); ∑l >t in 6t …..; 19 max, 6 on any t..
(3) Rounded indications are not a factor in the acceptability of welds
not required to be fully radiographed.
R
Rectify original repair
All weld is accepted
A
A
R
A
R
Remove entire weld and reweld…
Or
100% RT and rectify the repairs
R
R
R
Page 17 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
Sub Section C
PART UCS :
Material Requirements
UCS-6:
STEEL PLATES
(b)
UCS-56:
Steel plates conforming to SA-36, SA/CSA-G40.21 38W, and SA-283
Grades A, B, C, and D may be used for pressure parts in pressure vessels
provided all of the following requirements are met:
(1)
The vessels are not used to contain lethal substances, either liquid or
gaseous.
(2)
The material is not used in the construction of unfired steam boilers
[see U-1(g)].
(3)
With the exception of flanges, flat bolted covers, and stiffening rings,
the thickness of plates on which strength welding is applied does not
exceed 5⁄8 in. (16 mm).
REQUIREMENTS FOR POSTWELD HEAT TREATMENT
TABLE UCS-56
POSTWELD HEAT TREATMENT REQUIREMENTS FOR CARBON AND LOW ALLOY STEELS
Normal Holding
Temperature, °F
(°C), Minimum
Material
P-No. 1
Gr. Nos. 1, 2, 3
Gr. No. 4
Minimum Holding Time at Normal Temperature
for Nominal Thickness [See UW-40(f)]
Up to 2 in.
(50 mm)
1,100 (595)
1 hr/in. (25 mm),
15 min minimum
= not applicable
None
Over 2 in. to 5 in.
(50 mm to 125 mm)
2 hr plus 15 min for
each additional inch (25
mm) over 2 in. (50 mm)
Over 5 in.
(125 mm)
2 hr plus 15 min for
each additional inch (25
mm) over 2 in. (50 mm)
None
None
NOTES:
(1)
When it is impractical to postweld heat treat at the temperature specified in this
Table, it is permissible to carry out the postweld heat treatment at lower
temperatures for longer periods of time in accordance with Table UCS-56.1.
(2)
Postweld heat treatment is mandatory under the following conditions:
(a)
for welded joints over 1½ in. (38 mm) nominal thickness;
(b)
for welded joints over 11⁄4 in. (32 mm) nominal thickness through 11⁄2 in.
(38 mm) nominal thickness unless preheat is applied at a minimum
temperature of 200°F (95°C) during welding;
Page 18 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
(c)
UCS-57:
for welded joints of all thicknesses if required by UW-2, except postweld
heat treatment is not mandatory under the conditions specified below:
(1)
for groove welds not over ½in. (13 mm) size and fillet welds with a
throat not over ½in. (13 mm) that attach nozzle connections that have
a finished inside diameter not greater than 2 in. (50 mm), provided
the connections do not form ligaments that require an increase in shell
or head thickness, and preheat to a minimum temperature of 200°F
(95°C) is applied;
(2)
for groove welds not over 1⁄2 in. (13 mm) in size or fillet welds with a
throat thickness of 1⁄2 in. (13 mm) or less that attach tubes to a
tubesheet when the tube diameter does not exceed 2 in. (50 mm). A
preheat of 200°F (95°C) minimum must be applied when the carbon
content of the tubesheet exceeds 0.22%.
(3)
for groove welds not over 1⁄2 in. (13 mm) in size or fillet welds with a
throat thickness of 1⁄2 in. (13 mm) or less used for attaching
nonpressure parts to pressure parts provided preheat to a minimum
temperature of 200°F (95°C) is applied when the thickness of the
pressure part exceeds 11⁄4 in. (32 mm);
(4)
for studs welded to pressure parts provided preheat to a minimum
temperature of 200°F (95°C) is applied when the thickness of the
pressure part exceeds 11⁄4 in. (32 mm);
(5)
for corrosion resistant weld metal overlay cladding or for welds
attaching corrosion resistant applied lining (see UCL-34) provided
preheat to a minimum temperature of 200°F (95°C) is maintained
during application of the first layer when the thickness of the pressure
part exceeds 11⁄4 in. (32 mm).
RADIOGRAPHIC EXAMINATION
TABLE UCS-57
THICKNESS ABOVE WHICH FULL RADIOGRAPHIC EXAMINATION OF BUTT WELDED
JOINTS IS MANDATORY
P-No. & Group No. Classification
of Material
Nominal Thickness Above Which
Butt Welded Joints Shall Be Fully
Radiographed, in. (mm)
1 Gr. 1, 2, 3
11⁄4 (32)
3 Gr. 1, 2, 3
3⁄4 (19)
4 Gr. 1, 2
5⁄8 (16)
5A Gr. 1, 2
0 (0)
5B Gr. 1, 2
0 (0)
5C Gr. 1
0 (0)
…….and so on
Page 19 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
LOW TEMPERATURE OPERATION
UCS-66:
MATERIALS
FIG. UCS-66.2
DIAGRAM OF UCS-66 RULES FOR DETERMINING LOWEST MINIMUM DESIGN
METAL TEMPERATURE (MDMT) WITHOUT IMPACT TESTING
Establish nominal thickness [Note (1)] of welded parts, non welded parts, and
attachments under consideration both before and after corrosion allowance is
deducted (tn and tn – c, respectively), and other pertinent data applicable to the
nominal thickness such as:
All applicable loadings [Note (2)] and coincident minimum design metal temperature
(MDMT)
Step 1
Materials of construction
E= joint efficiency [Note (3)]
tn= nominal non-corroded thickness [Note (1)], in. (mm)
tr= required thickness in corroded condition for all applicable loadings [Note (2)],
based on the applicable joint efficiency [Note (3)], in. (mm)
Applicable curve(s) of Fig. UCS-66
c= corrosion allowance, in. (mm)
Step 2
Select MDMT from Fig. UCS-66 [Note (4)] for each
nominal non-corroded governing thickness [Note (5)].
Determine Ratio: (trE*) /( tn – c)
Step 3
Step 4
[Notes (3), (6), (7), and (8)]
Using Ratio from Step 3 to enter ordinate
of Fig. UCS-66.1, determine reduction in Step 2
MDMT [Note (9)].
Step 5
Determine adjusted MDMT for governing
thickness under consideration.
Repeat for all governing thicknesses [Note (5)] and take warmest
value as the lowest allowable MDMT to be marked on nameplate
for the zone under consideration [Note (10)]. See UG-116.
Step 6
See UG-99(h) for coldest recommended metal temperature during
hydrostatic test [Note (6)].
See UG-100(c) for coldest metal temperature permitted during
pneumatic test [Note (6)].
Optional
Required
Page 20 of 27
Refer UG-20(f) also
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
FIG. UCS-66 IMPACT TEST EXEMPTION CURVES (CONT’D)
NOTES:
(1) Curve A applies to:
(a) all carbon and all low alloy steel plates, structural shapes, and bars not listed
in Curves B, C, and D below;
(b)
SA-216 Grades WCB and WCC if normalized and tempered or water-quenched
and tempered; SA-217 Grade WC6 if normalized and tempered or waterquenched and tempered.
(2) Curve B applies to:
(a) SA-216 Grade WCA if normalized and tempered or water-quenched and
tempered SA-216 Grades WCB and WCC for thicknesses not exceeding 2 in.
(50 mm), if produced to fine grain practice and water-quenched and
tempered
Page 21 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
SA-217 Grade WC9 if normalized and tempered
SA-285 Grades A and B
SA-414 Grade A
SA-515 Grade 60
SA-516 Grades 65 and 70 if not normalized
SA-612 if not normalized
SA-662 Grade B if not normalized
SA/EN 10028-2 P295GH as-rolled;
(b)
except for cast steels, all materials of Curve A if produced to fine grain
practice and normalized which are not listed in Curves C and D below;
(c)
all pipe, fittings, forgings and tubing not listed for Curves C and D below;
(d)
parts permitted under UG-11 shall be included in Curve B even when
fabricated from plate that otherwise would be assigned to a different curve.
(3) Curve C applies to:
(a) SA-182 Grades 21 and 22 if normalized and tempered
SA-302 Grades C and D
SA-336 F21 and F22 if normalized and tempered
SA-387 Grades 21 and 22 if normalized and tempered
SA-516 Grades 55 and 60 if not normalized
SA-533 Grades B and C
SA-662 Grade A;
(b)
all material of Curve B if produced to fine grain practice and normalized and
not listed for Curve D below.
(4) Curve D applies to:
SA-203
SA-508 Grade 1
SA-516 if normalized
SA-524 Classes 1 and 2
SA-537 Classes 1, 2, and 3
SA-612 if normalized
SA-662 if normalized
SA-738 Grade A
SA-738 Grade A with Cb and V deliberately added in accordance with the
provisions of the material specification, not colder than −20°F (−29°C)
SA-738 Grade B not colder than −20°F (−29°C)
SA/AS 1548 Grades 7-430, 7-460, and 7-490 if normalized
SA/EN 10028-2 P295GH if normalized [see Note (e)(3)]
SA/EN 10028-3 P275NH
Page 22 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
UCS-68(c)
If postweld heat treating is performed when it is not otherwise a
requirement of this Division, a 30°F (17°C) reduction in impact testing
exemption temperature may be given to the minimum permissible
temperature from Fig. UCS-66 for P-No. 1 materials. The resulting
exemption temperature may be colder than −55°F (−48°C).
Page 23 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
MANDATORY APPENDIX 8
METHODS FOR
LIQUID PENETRANT EXAMINATION (PT)
8-3
EVALUATION OF INDICATIONS
An indication of an imperfection may be larger than the imperfection that
causes it; however, the size of the indication is the basis for acceptance
evaluation. Only indications with major dimensions greater than 1⁄16 in. (1.5
mm) shall be considered relevant.
8-4
(a)
A linear indication is one having a length greater than three times
the width.
(b)
A rounded indication is one of circular or elliptical shape with the
length equal to or less than three times the width.
(c)
Any questionable or doubtful indications shall be reexamined to
determine whether or not they are relevant.
ACCEPTANCE STANDARDS
These acceptance standards shall apply unless other more restrictive standards
are specified for specific materials or applications within this Division. All surfaces
to be examined shall be free of:
(a)
relevant linear indications;
(b)
relevant rounded indications greater than 3⁄16 in. (5 mm);
(c)
four or more relevant rounded indications in a line separated by 1⁄16
in. (1.5 mm) or less (edge to edge).
Indication size
> 5.0 mm
Relevant: Noted & Not Acceptable
(Rejected / Repair)
1.5 – 5.0 mm
Relevant: Noted & Acceptable
< 1.5 mm
Irrelevant: Acceptable
Page 24 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
Code Interpretations
Interpretation:
Subject:
Date Issued:
File:
VIII-1-01-02
Section VIII, Division
Addenda); UG-99(g)
September 8, 2000
BC00-393
1
(1998
Edition,
1999
Question: A vessel is subjected to the hydro test under UG-99.
During the test, a leak is detected from the gasket seat
of a permanent flanged joint. In meeting the
requirements of UG-99(g) in Section VIII, Division 1,
may the hydro test be accepted if the flanged joint and
the vessel as a whole are found to be completely tight
after the pressure is reduced to not less than the test
pressure divided by 1.3?
Reply:
Yes.
Interpretation:
VIII-1-98-86
Subject:
Section VIII, Division 1 (1998 Edition, 1998 Addenda);
UG-99(b) and (c)
Date Issued:
October 25, 1999
File:
BC99-346
Question: Do the requirements of UG-99(b) and (c) in Section VIII,
Division 1 preclude the use of a temperature recorder for
the test medium during the performance of the
hydrostatic test?
Reply:
No.
Interpretation:
VIII-1-98-110
Subject:
Section VIII, Division 1 (1998 Edition, 1999 Addenda);
UW-40(c) and UCS-56(d)(3)
Date Issued:
March 22, 2000
File:
BC00-082
Question: In complying with the requirements of UW-40(c) and
UCS-56(d)(3) in Section VIII, Division 1, is it necessary
to have thermocouples attached to both the inside and
outside surfaces of a vessel during postweld heat
treatment?
Reply:
No.
Page 25 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
Interpretation:
VIII-1-01-85
Subject:
Section VIII, Division 1 (1998 Edition, 2000 Addenda);
UW-31(d) and UW-33(a)
Date Issued:
September 24, 2001
File:
BC01-325
Question(1):In meeting the requirements of Section VIII, Division 1,
may the over thickness tolerance, as permitted by the
plate specification, be excluded from the maximum offset
in evaluating the alignment tolerances of UW-31(d) and
UW-33?
Reply (1): No.
Question(2):May the maximum offset per UW-33(a) be increased by
an amount equal to the difference between the actual
thickness and the required thickness?
Reply (2): No.
Page 26 of 27
ASME Sec VIII Div 1– Basics – nrs (Rev.5 – 12 Mar 2010)
Information
Basics:
the simplest and most important facts
Concept:
Principle or idea
Philosophy: use of principles that govern and influence judgment
Page 27 of 27