Piping Inspector Interview Questionnaire
No.
1.
2.
3.
Question
What is ASME B31.3 all about?
ASTM stands for?
What is NACE MR0175 all about?
4.
What is the difference between a PIPE and
TUBE?
5.
In what service does ASTM A333 pipe
specification is applicable?
What ASTM pipe specification usually used
for High Temperature Service
ASTM A105 is the specs for what?
How many bolt holes does a 3” 150#
flange have? Same size but 300#, how
many bolt holes?
In the installation of flanges on horizontal
pipe, how do you orient the bolt holes
with respect to the vertical centerline?
What is the maximum bolt holes offset
between the two flanges?
In orifice flange, what is the required
internal (root) weld profile?
In weld fit-up, What is the tolerance of
weld encroachment (toe to toe)
What is the recommended min. tack weld
size and how many locations are required
for 6” pipe.
What depth shall be removed by grinding
or machining after flame cutting?
What is the usual cleaning method of pipe
internals before hydrotest?
If P is your design pressure, what is the
usual test pressure for a) Hydrotest? b)
Pneumatic Test
As per code and standard practice, what is
the minimum holding test pressure
holding time?
In testing underground pipe installation,
what is the minimum holding time?
In testing and flushing of stainless steel,
what is the required water quality
requirement?
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Answer Key Word
Process Piping Code
American Standard for Testing & Materials
Material Resistant to Sulfide Stress Cracking
(SSC) - for Sour Service application.
The difference is in size designation with
respect to its outside diameters. PIPE NPS 12
and smaller have Outside Diameters (OD)
numerically greater than their corresponding
sizes, whereas for TUBE the Outside Diameter is
numerically identical with their size designation
for all sizes.
Low Temperature service
ASTM A335
Flanges
3”-150# = 4 holes
3”-300# = 8 holes
The bolt shall STRUDDLE to vertical centerline
2.4 mm
Flush
20 mm or 3 x thickness, whichever it lesser
3 x 12.5 mm (tack weld thickness x Length and
for 6” size min. location is 4 (Saudi Aramco
standard).
1.5 mm
Flushing by water, flushing by air, Mechanical
cleaning for large pipe sizes
a) For Hydrotest, Test pressure is 1.5 x P.
b) For Pneumatic, Test Pressure is 1.1 x P.
2 hours
24 hours
Chloride is less than 50 ppm
Piping Inspector Interview Questionnaire
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The nominal thickness of pipe is T. What is
minimum acceptable thickness (or mill
tolerance).
Stainless steel pipe is directly in contact
with Carbon steel support, is this allowed?
And why?
In smaller pipe sizes (in pipe schedule
table) the Nominal Pipe size (NPS)
designation is numerically smaller than
the corresponding Outside Diameter (OD),
whereas in larger sizes the NPS is
numerically equal to OD. Question: At
what size of pipe the OD and NPS are
identical.
You have pipe schedule table for carbon
steel (ASME B36.10), can you use this for
stainless steel? Why?
During Pressure Testing of piping
system/components, there will be
possibility that the system will be over
pressurized. What additional safety
equipment do you install to avoid over
pressurizing the system?
What is the pressure setting of relieve
valve with respect to the test pressure?
What is SMYS?
What is the usual Range of Pressure Gauge
to be used in pressure testing, with
respect to test pressure?
For above ground pipe, what is the
minimum distance from the bottom of
pipe to the ground level?
What is the minimum distance
requirement between pipe to pipe and/or
pipe to structure crossing.
What is the purpose of Check valve?
What ASME designate Flange Rating/Class
Is the flange rating/Class based only on
pressure?
32
Enumerate the 7 flange ratings/class?
33
What is a Miter Bend?
34
In socket welding, what is the gap
required between the pipe and the
Not less than 12.5% (Min. is .875 x T).
Not allowed because it will create bi-metallic
(galvanic) corrosion.
14” and above.
No, difference in thickness for same pipe
size/schedule of some size/schedule
combination.
Install relief valve
Usual Practice (Aramco standard) is 5% above
the test pressure.
Specified minimum yield strength
The Pressure Gauge shall be 30 to 80% of test
pressure.
300 mm
50 mm
To prevent flow reversal.
ASME B16.5
No.
It is based on Pressure/Temperature
combination.
Class 150#, 300#,400#, 600#, 900#, 1500# &
2500#
Sections of straight pipes welded together to
produce the required bend (i.e. 90 deg bend, 45
deg bend, etc.).
Gap is 1.5 to 3 mm. By push-pull technique
(push the pipe completely against the socket,
Piping Inspector Interview Questionnaire
socket? How to ensure the required gap is
maintained?
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40
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44
mark the end of socket to the pipe and pull it
back to required gap. Can also be verified by RT
to check the gap after welding the socket).
What is PMI? What is MPI?
PMI is Positive Material Identification
MPI is Magnetic Particle Examination
What is RTR? FRP?
RTR - Reinforced Thermo-Resin; FRP – Fiber
Reinforced Plastic.
What is the requirement of bolt protrusion 2 to 3 threads protrusion.
in flanges?
Latest Rev. of ISO Drawings; WPS applicable to
When performing Fit-up Inspection, what
the joint and Project specifications and
documents will you use as your basis or
Procedures.
reference?
As per ASME B 31.3, for Carbon steel, at
Above 25 mm need preheat
what Thickness you need to do preheat?
Metal surface Temperature Below 10 deg C
And what is the metal temperature in
need preheat
which you need to preheat?
What is the difference between a short
Long radius – R = 1.5 x D; Short radius – R = D.
radius and long radius elbow?
Ni content shall not be more than 1%. The
When you are performing material
receiving of NACE MR0175 pipe materials, material should have been heat treated above
the Lower critical Temperature and Hardness
what 3 main items in the Material Test
shall not be more than 22 HRC.
certificates you need to check?
The items is a Flange: WNRF means Weld neck
If you have specs: 4” sch. 40 x WNRF,
Raise Face, A105 is for the chemical
A105, B16.5, what is WNRF? For what is
composition requirement of the material used,
A105 required, For what is B16.5 require
B16.5 is the dimension standard used and the
and to what is sch. 40 required?
schedule 40 is for the thickness requirement of
the Neck.
Impact Test
What Mechanical Testing is distinctly
requirement in Low Temperature service
application
Please explain buttering used in joint fitButtering is the weld build up on base metal to
up
maintain fit-up alignment requirement, bevel
defect or other purpose.