CONSTRUCTION STANDARD

FIELD PNEUMATIC LEAK TESTING

8-2CS

DATE: 01 SEP 2003 ENGINEERING SERVICES BY KBR TECHNICAL SERVICES, INC. PAGE 1 OF 11

TABLE OF CONTENTS

Section Title Page No.

1. GENERAL ......................................................................................................................................1
1.1 Scope..............................................................................................................................................1
1.2 Testing Procedure ..........................................................................................................................1
1.3 Definitions .......................................................................................................................................1
2. TEST PLANNING...........................................................................................................................1
2.1 General ...........................................................................................................................................1
2.2 Required Nondestructive Examinations .........................................................................................2
2.3 Check Test Pressure Calculation ...................................................................................................3
2.4 Scheduling of Test ..........................................................................................................................3
2.5 Minimum Metal Temperature..........................................................................................................4
3. TESTING PROCEDURES AND TEST RECORDS........................................................................4
3.1 Preparation and Safety ...................................................................................................................4
3.2 Test Records...................................................................................................................................4
3.3 Technique .......................................................................................................................................6
3.4 Evaluation .......................................................................................................................................6
3.5 Repairs............................................................................................................................................7

APPENDIX I - EXCLUSION DISTANCES ...................................................................................10

1. GENERAL

1.1 Scope

1.1.1 This Standard covers the preparation, arrangement, procedures, and evaluation criteria for pneumatic
leak testing in the field.

1.1.2 The principle objective of the method described herein is the detection, location, and evaluation of leaks
within an assembly. This procedure is applicable to piping and piping systems within the scope of ASME B31.3,
"Process Piping".

1.2 Testing Procedure

A written detailed procedure incorporating applicable local safety regulations shall be followed which includes
personnel training and certification, test equipment and specifications.

1.3 Definitions

1.3.1 "Internal Design Gauge Pressure": The design pressure of the piping system as shown in the pipeline
line list and as defined in ASME B31.3.

1.3.2 "Piping System": A system used for conveying a fluid or transmitting pressure through cylindrical
assemblies of pipe, tube, fittings, and other piping components. A piping system test may contain pressure
vessels or other equipment within the jurisdiction and/or scope of other codes or regulations.

1.3.3 "Repair": The work necessary to stop weld joint leaks or replace seals or gaskets for consummation of
the pressure test.

1.3.4 "Test Pressure": Test pressure shall be 110% of design pressure.

2. TEST PLANNING

2.1 General

2.1.1 The general arrangement for pneumatic leak testing shall be as shown in Figure 1.
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FIELD PNEUMATIC LEAK TESTING

8-2CS

DATE: 01 SEP 2003 ENGINEERING SERVICES BY KBR TECHNICAL SERVICES, INC. PAGE 2 OF 11

2.1.2 Required relief valve setting pressure shall be in accordance with Figure 1.

2.1.3 The range of the pressure gauges to be used shall be in accordance with Figure 1.

2.1.4 The test fluid shall be dry nitrogen or clean, dry, oil-free air.

2.1.5 Exclusion distances have been calculated, using the equations and data in the Appendix I.

2.1.6 Plans for access to the test area shall be based on the calculated stored energy and the requirements of
Figure 2.

2.1.7 All flanges shall be securely taped and a pinhole provided in the tape for leak detection.

2.1.8 All anchors, supports, guides and hangers shall be checked for correct installation. Expansion joints with
tie rods and retaining nuts shall be installed in the test position in accordance with manufacturer's
recommendations.

2.1.9 Blinds at valves and system extremities shall be checked for correct location and thickness.

2.1.10 All valves in the test system shall be fully open. Check valves shall allow free pressuring and
depressuring by removal and subsequent replacement of internals.

2.2. Required Nondestructive Examinations (for piping systems to be pneumatically tested)

2.2.1 When individual pipe spools have been hydrostatically tested to the requirements of ASME B31.3 in a
fabrication shop or in a field lay-down area, the following Nondestructive Examinations are required for field-
welded seams prior to pneumatic testing:

a. All field butt welded seams: 100% radiography using the acceptance criteria for "Normal Fluid Service" of
Table 341.3.2A of ASME B31.3.

b. All field non-butt pressure boundary welds: 100% magnetic particle (for ferritic material) or liquid penetrant
(for non-ferritic material) of root and final passes.

c. The limited access area applies only to those field welds not previously pressure tested.

2.2.2 If the piping spools have not been hydrostatically tested to the ASME B31.3 required leak test pressure,
the following Nondestructive Examinations are required prior to the pneumatic test:

a. All butt welds: 100% radiography of, using the acceptance criteria for "Normal Fluid Service" of
Table 341.3.2A of ASME B31.3.

b. All non-butt pressure boundary welds: 100% magnetic particle (for ferritic material) or liquid penetrant (for
non-ferritic material) of root (if possible) and final passes.

c. The limited access area applies to all components of the pressurized system.

2.2.3 For pipe that is equal to or smaller than 24 NPS, a field pneumatic test may be conducted without
imposing any additional Nondestructive Examinations beyond those listed by the material and piping
specifications if the following criteria are satisfied:

a. The pneumatic test pressure is equal to or less than 100 psig (689 kPa(gage)), and
 CONSTRUCTION STANDARD

FIELD PNEUMATIC LEAK TESTING

8-2CS

DATE: 01 SEP 2003 ENGINEERING SERVICES BY KBR TECHNICAL SERVICES, INC. PAGE 3 OF 11

b. The total stored energy in the system being tested is less than 100 million ft-lbs (135.58x106J). (See the
equation below for determination of stored energy). For welded pipe that did not receive a mill or shop
hydrostatic test, the total stored energy is limited to 25 million ft-lbs (33.89x106J).

Stored Energy:

E = 360 (P+14.7) V {1- [14.7/(P+14.7)]0.286} ft·lbs

Where:

E = stored energy in ft-lbs

P = required test gage pressure in (psig)
V = total volume under test pressure in cubic feet

E = 2500 (P+101.35) V {1- [101.35/(P+101.35)]0.286} J (joules)

Where:

E = stored energy in J (joules)

P = required test gage pressure in (kPa (gage))
V = total volume under test pressure in m3

2.2.4 For piping systems where the hoop stress (Sh) resulting from the pneumatic leak test pressure does not
exceed 7000 psi (48.26 MPa) (not limited by size or pressure), a field pneumatic test may be conducted without
imposing any additional Nondestructive Examinations beyond those listed by the material and piping
specifications. Note: Sh = Pt Do/(2tnom) where Sh is hoop stress, Pt is the pneumatic test pressure, Do is the pipe
outside diameter, and tnom is the nominal pipe wall thickness, may be used to determine the hoop stress during
the test. Personnel, in addition to those involved with the testing, may be allowed in the limited access area
after the pressure has been reduced to the inspection (design pressure) level.

2.2.5 Pressure vessels that have been previously pressure tested at a pressure greater than the system
pneumatic test pressure may be included in a pneumatically tested system. Pressure vessels not previously
pressure tested shall not be subjected to a pneumatic test unless specific agreement is obtained from the
responsible Vessel Mechanical Engineer who will define the appropriate NDE requirements.

2.3 Check Test Pressure Calculation

2.3.1 Piping and piping systems shall be subjected to a pneumatic test at the pressure required by the drawings
and specifications.

2.3.2 As a precautionary measure against overpressuring, the following formula shall be used by the field to
calculate the check test pressure.

Pt = 1.10 P

where: Pt = check test pressure, psig [kPa (gage)]

P = internal design gauge pressure, psig [kPa (gage)]
If the required test pressure exceeds Pt, the required test pressure shall be verified.

2.4 Scheduling of Test

2.4.1 The leak test shall be done after heat treatment, if heat treatment is required.

2.4.2 Pneumatic tests shall not be performed in the rain.

2.4.3 The test pressure shall not be applied until the piping or piping system and the pressurizing medium are
at about the same temperature.
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FIELD PNEUMATIC LEAK TESTING

8-2CS

DATE: 01 SEP 2003 ENGINEERING SERVICES BY KBR TECHNICAL SERVICES, INC. PAGE 4 OF 11

2.5 Minimum Metal Temperature

2.5.1 The minimum metal temperature during the field pneumatic leak test must not be less than the warmer of
the following:

a. The coldest specified temperature in Table I for the most restrictive category of pressure retaining material.

b. The warmest Minimum Design Metal Temperature (MDMT) of ASME Section VIII, Division 1 or Division 2
vessels included in the test, if such vessels have been previously hydrotested per the Code.

c. For other equipment constructed of impact tested materials, and having been previously hydrotested per
their construction codes, the minimum metal temperature for the leak test may be lowered to 30oF (17oC)
warmer than the warmest temperature at which the materials were impact tested.

2.5.2 For piping systems that contain equipment that has been in service, the design engineer shall specify the
minimum metal temperature for pneumatic testing. If the design engineer has not done so, the Chief
Construction Engineer shall contact him and request this information in writing.

2.5.3 Pressurizing shall not commence until the metal temperature has reached the required value or warmer.

2.5.4 Consideration shall be given to heat loss during the test to assure that the minimum metal temperature is
retained while the piping or piping system is pressurized.

3. TESTING PROCEDURES AND TEST RECORDS

3.1 Preparation and Safety

3.1.1 Establish a limited access area and pressure control point in accordance with Figure 2. Signs which read
"PNEUMATIC TEST IN PROGRESS - ACCESS BY PERMISSION ONLY" shall be posted at the perimeter of
the limited access area. Only personnel involved in the particular test operation being performed may be within
the limited access area. For example, during the pressurizing, those personnel who will examine the joints shall
be outside the limited access area.

3.1.2 Two (2) personnel shall be at the Pressure Control Point monitoring the gauge and recorder whenever the
system contains pressure.

3.1.3 For field joints, review NDE and PWHT records to assure that all NDE and PWHT has been performed
and is acceptable, prior to pressurizing the system.

3.1.4 If tightening is required to stop leaks, isolate the immediate work area from personnel not necessary for
the tightening operation. Personnel performing the tightening operation shall remain clear of the gasket plane
projection.

3.2 Test Records

3.2.1 Records shall be kept of testing operations and a complete report, including a copy of the records, charts,
etc., shall be forwarded to KBR or its designee after the operations are completed. The records shall include
the following:

a. Date of test.
b. Identification of system tested.
c. Location/Unit.
d. Test media.
e. Test pressure.
f. Metal temperature.
g. Certification by tester.
h. Approval by Owner's Inspector with sign off.
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FIELD PNEUMATIC LEAK TESTING

8-2CS

DATE: 01 SEP 2003 ENGINEERING SERVICES BY KBR TECHNICAL SERVICES, INC. PAGE 5 OF 11

TABLE I
MINIMUM METAL TEMPERATURE AT TIME OF TESTING (Note 1)
Nominal
Wall Coldest Metal Temp
Materials and Basis Description PWHT
Category Thickness
(Notes 1 and 2) (Note 6)
in. (mm) o o
(Note 5) F C

P1 or P3 carbon or low alloy classified in

A Table A-1 (Note 6) as -20oF (-28.8 oC) or
15 + 30
(Note 3) Curve B, C, or D in Figure 323.2.2. ≤3/4 (19) No 7.2
= 45
(Note 6) Coldest temperature from Curve B at
3/4 in. (19 mm) +30o F (+17o C)
Category A welded spools that have
been PWHT because one or more of the
Per Per Fig.
B Nominal wall thicknesses at the weld is
>3 /4 (19) Yes Fig. 323.2.2, 323.2.2,
(Note 6) >3/4 in. (19 mm). Coldest temperature
Curve B Curve B
from Curve B Fig. 323.2.2 using
maximum nominal thickness.
C P1 or P3 carbon or low alloy classified in
53 + 30
(Note 4) Table A-1 (Note 6) as Curve A, also ≤3/4 (19) No 28
= 83
(Note 6) including valve body castings per Note 4

Category C spools that are PWHT, Max. nominal

D Yes Per Curve A Per Curve A
maximum nominal thickness at weld Thickness

Combination of Category A, B, C, or D.
E -- -- -- --
The warmest temperature controls.
P3, P4 or P5 alloy steels classified in
F Table A-1 with a minimum temperature of Same as Same as
≤1/2 (13) No
(Note 6) -20o F(-28.8o C) that are not required to Category A Category A
be PWHT (t ≤1/2 in.) (13 mm)
Category F spools for which the entire may be Same as Same as
G Yes
welded assembly is required to be PWHT >1/2 (13) Category B Category B

H Fully austenitic welded piping assemblies No Limit No 32 0

NOTES TO TABLE I:

1. Materials in welded piping assemblies (spools) or systems consisting of pipe, forgings, fittings, valves and
supports. Applies to flanges, fittings, and valves conforming to ANSI or MSS standards only.

2. ASTM materials unless otherwise noted. ASME materials have the same designation as the ASTM
materials, but prefixed by an "S" (e.g., SA-516). ASME materials shall be in accordance with
ASME Section II-Part A.

3. Cast steel valve bodies must be A-216 Grade WCA normalized and tempered or quenched and tempered,
or A-216 Grades WCB or WCC if produced to fine grain practice and water-quenched and tempered, or
A217 Grade WC9 if normalized and tempered.
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FIELD PNEUMATIC LEAK TESTING

8-2CS

DATE: 01 SEP 2003 ENGINEERING SERVICES BY KBR TECHNICAL SERVICES, INC. PAGE 6 OF 11

4. Includes cast steel valve body materials that are A-216 Grades WCB and WCC if not made to fine grain
practice and water quenched and tempered, and A-217 Grade WC6 normalized and tempered or water-
quenched and tempered.

5. The thicknesses indicated for flanges, fittings, forgings, and castings are at the ends at which butt welds are
made.

6. All table and figure references are to ASME B31.3 - 1996. For PWHT definitions and requirements, refer to
Table 331.1.1.

3.3 Technique

3.3.1 Take a temperature reading of metal to assure that it is warmer than the coldest temperature allowed.

3.3.2 The test fluid shall be introduced into the piping or piping system gradually until the pressure is the lesser
of one-half of the test pressure or 25 psig [172 kPa (gage)]. At this point, the pressure shall be maintained for
10 minutes, followed by a preliminary check.

3.3.3 Chloride-free leak detection fluid shall be applied (using a chemist's wash bottle or other suitable means)
to the areas of interest. Ordinary household soaps or detergents are not permitted. If tightening is required to
stop leaks, isolate the immediate work area from personnel not necessary for the tightening operation.

3.3.4 The pressure shall be gradually increased to the test pressure in steps equal to or less than those shown
in Table II. Piping strains shall be allowed to equalize between steps. Once the test pressure has been attained
and held for 10 minutes, the pressure shall be reduced to the internal design gauge pressure.

TABLE II
TEST PRESSURE STEPS

PT < 75 psig (5 barg) PT ≥ 75 psig (5 barg)

Step Pressure Step Pressure
Lesser of 50% PT or
1 1 25 psig (1.7 barg)
25 psig (1.7 barg)
2 90% of PT 2 25% of PT
3 100% of PT 3 50% of PT
4 PD 4 75% of PT
5 90% of PT
6 100% of PT
7 PD

PT = Test Pressure
PD = Design Pressure

3.3.5 The internal design gauge pressure shall then be held for at least 10 minutes and until all joints and
connections are examined for leaks.

3.3.6 Perform a visual inspection of all joints and connections at internal design gauge pressure using leak
detection fluid. This inspection shall be witnessed by the Owner's Inspector or his delegated inspector.

3.4 Evaluation

Any bubbles observed because of seepage shall be considered rejectable.

 CONSTRUCTION STANDARD

FIELD PNEUMATIC LEAK TESTING

8-2CS

DATE: 01 SEP 2003 ENGINEERING SERVICES BY KBR TECHNICAL SERVICES, INC. PAGE 7 OF 11

3.5 Repairs

Repairs shall be re-examined by the same procedure. Acceptability of repaired areas shall be determined by
the same acceptance standards.

FIGURE 1
GENERAL ARRANGEMENT FOR PNEUMATIC LEAK TESTS
 CONSTRUCTION STANDARD

FIELD PNEUMATIC LEAK TESTING

8-2CS

DATE: 01 SEP 2003 ENGINEERING SERVICES BY KBR TECHNICAL SERVICES, INC. PAGE 8 OF 11

Limited Access Boundary (See Note 1)

R
R
R
R Piping

EXCHANGER

R
R
R

n Zon e
Boundary of Exclusio

R = Exclusion Distance = Projectile Range

FIGURE 2

EXCLUSION ZONE
 CONSTRUCTION STANDARD

FIELD PNEUMATIC LEAK TESTING

8-2CS

DATE: 01 SEP 2003 ENGINEERING SERVICES BY KBR TECHNICAL SERVICES, INC. PAGE 9 OF 11

NOTES:

The projectile model selected, a 2 in. x 12 in. (50 mm x 300 mm) long nozzle detaching from the main pipe or
equipment item results in the following exclusion zone distances which have all been rounded up to multiples of
33 feet (10 m). These distances shall be observed for all pneumatic tests.

EXCLUSION
TEST PRESSURE psia (kPa (absolute))
DISTANCE
From To feet (meter)

14.5 (100) 72.5 (500) 66 (20)

72.6 (501) 145 (1000) 98 (30)

145.1 (1001) 203 (1400) 131 (40)

203.1 (1401) 261.0 (1800) 164 (50)

261.1 (1801) 319.0 (2200) 197 (60)

319.1 (2201) 377.0 (2600) 230 (70)

377.1 (2601) 435.0 (3000) 262 (80)

435.1 (3001) 522.0 (3600) 295 (90)

522.1 (3601) 580.0 (4000) 328 (100)

580.1 (4001) 667.0 (4600) 361 (110)

667.1 (4601) 754.0 (5200) 394 (120)

754.1 (5201) 841.0 (5800) 427 (130)

841.1 (5801) 928.0 (6400) 459 (140)

928.1 (6401) 1000.5 (6900) 492 (150)

1000.6 (6901) 1087.5 (7500) 525 (160)

1087.6 (7501) 1160.0 (8000) 558 (170)

over 1160.0 (8000) Not Recommended

 CONSTRUCTION STANDARD

FIELD PNEUMATIC LEAK TESTING

8-2CS

DATE: 01 SEP 2003 ENGINEERING SERVICES BY KBR TECHNICAL SERVICES, INC. PAGE 10 OF 11

APPENDIX I
EXCLUSION DISTANCES

1. Credible Failure Modes

1.1 The access to the system to be pneumatically tested is determined by calculating the distance traveled by a
projectile, which is considered to be the most likely type of failure.

1.2 The distance traveled by such a projectile is a function of mass, initial velocity after detachment and its
aerodynamic profile.

1.3 For piping systems the possible types of failure are:

• Brittle fracture of a pipe creating small shrapnel projectiles with small aerodynamic profile

• Buttweld failure of pipes up to 6 NPS causing them to whip or “snake”. However, the remainder of the pipe
still attached restricts this effect and therefore the exclusion distance does not have to be large.

• Although it would be catastrophic, buttweld failure of pressure vessels, exchangers or equipment within a
piping system is not considered to be a credible event during a pneumatic test, since all this equipment will
have been shop hydrotested.

• Sudden detachment of a branch welded nozzle connection or other pipe attachment. This would result in a
tumbling projectile, which could travel a large distance and could cause significant injury or loss of life. It is
not practicable nor possible to 100% radiograph branch welds due to their geometry. Therefore, a failure
here is considered to be far more likely than buttwelds which have been 100% radiographed.

1.4 Exclusion distances have therefore been calculated for the "guillotine failure" and detachment of a small
nozzle connection welded to a larger pipe or to an item of equipment.

2. Calculation of Exclusion Distances

2.1 Calculations were based on the references and equations quoted in Section 3. of this Appendix.

2.2 The following assumptions were made :

a. The largest dead-ended branch connections in a piping system will generally be an instrument, vent or
drain connection with a maximum diameter of 2 NPS. Furthermore analysis shows that for nozzle necks
exceeding 12 in. (300 mm) long the distance traveled by the projectile will not increase significantly.
Therefore, the credible projectile is 2 NPS, 12 in. (300 mm) long.

b. The initial velocity at detachment depends on the stored energy of the compressed gas inside the system.

c. No energy is transferred to the nozzle from the compressed gas in the main pipe run or equipment item.

d. All the energy from the compressed gas in the branch connection is adiabatically converted into kinetic
energy when the nozzle becomes detached.

e. The energy required to break the branch weld, overcome friction losses as the gas escapes and to cause
the tumbling nozzle to rotate is ignored.

f. The drag area of the nozzle as it tumbles is the average of its face areas.

g. The only resistance to the flight of the nozzle is the still air.
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2.3 Above assumptions d, e and f are conservative whereas assumptions a, b, c, and g are not. On balance, it
is considered that the deviations cancel out and that the rounded up calculated distances traveled by the
projectile tabulated in Fig. 2 are realistic.

3. References and Equations Used To Calculate Exclusion Distances

3.1 References

Baker W E et al "Explosion Hazards and Evaluation"

Elesevier Scientific Publishing Company, Amsterdam, 1983, pp 463-474

Baker W E "Blast and Blast Fragments from Bursting Pressure Vessels" ASME Journal 83-PVP-61.

3.2 Equations

Er = 1000·(P-Po)·V·ln(P/Po) Stored energy within the nozzle

Er = 0.5·M·Vo2 Kinetic energy = stored or potential energy above

Fdp = (dair·Cd·Ad·Vo)/M Dimensionless force parameter

Rdp = (dair·Cd·Ad·Range)/Mg Dimensionless force parameter

Rdp = 0.2·Fdp0.61 Curve fit of Rdp to Fdp

3.3 Constants and variables

P = Test pressure (kPa absolute)

Po = Ambient pressure (101 kPa)
V = Volume of projectile (m3)
M = Mass of projectile (kg)
Vo = Initial velocity of projectile (m/s)
dair = Density of air (1.614 kg/m3)
Cd = Drag coefficient (0.99)
Ad = Drag area (m2)
R = Range or travel distance (m)