4.2.19
Performing Pressure Tests on Gas
Distribution Lines
Gas personnel must understand how to perform pressure
tests on gas distribution lines to ensure the system is gas
tight.
In this module you will learn to identify:
(1) NFPA 54 regulations that apply to pressure testing of a
propane distribution system
(2) Basic elements of pressure testing
(3) Procedures commonly used to pressure test propane piping
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 1
NFPA 54 Regulations that Apply to Pressure Testing
NFPA 54
2002
7.1.4.1 Test pressure shall be measured with a manometer or with a
pressure measuring device designed and calibrated to read, record,
or indicate a pressure loss due to leakage during the pressure test
period. The source of pressure shall be isolated before the pressure
tests are made. Mechanical gauges used to measure test pressures
shall have a range such that the highest end of the scale is not
greater than 5 times the test pressure.
7.1.4.2 The test pressure to be used shall be no less than 1-½ times the proposed
maximum working pressure, but not less than 3 psi, irrespective of design pressure.
7.1.4.3 Test duration shall be not less than ½ hour for each 500 cubic feet of pipe
volume or fraction thereof. When testing a system having a volume less than 10
cubic feet or a system in a single-family dwelling, the test duration shall be a
minimum of 10 minutes. The duration of the test shall not be required to exceed 24
hours.
4.2.19 Student Book  © 2004 Propane Education & Research Council
NFPA 54 Regulations that Apply to Pressure Testing
NFPA 54
2002
7.1.1.3 Where repairs or additions are made following the pressure
test, the affected piping shall be tested. Minor repairs and additions
are not required to be pressure tested provided that the work is
inspected and connections are tested with a non-corrosive leakdetecting fluid or other leak-detecting methods approved by the
authority having jurisdiction.
7.1.1.4 Where new branches are installed from the point of delivery to new
appliance(s), only the newly installed branch(es) shall be required to be pressure
tested. Connections between the new piping and the existing piping shall be tested
with a non-corrosive leak-detecting fluid or approved leak-detecting methods.
7.1.1.5 A piping system shall be tested as a complete unit or in sections. Under no
circumstances shall a valve in a line be used as a bulkhead between gas in one
section of the piping system and test medium in an adjacent section, unless two
valves are installed in series with a valved “tell tale” located between these valves.
A valve shall not be subjected to the test pressure unless it can be determined that
the valve, including the valve closing mechanism, is designed to safely withstand
the pressure.
4.2.19 Student Book  © 2004 Propane Education & Research Council
Pages 1 & 2
Identifying Basic Elements of Pressure Testing
Test Medium. According to NFPA 54, 7.1.2, the test medium shall be air,
nitrogen, or carbon dioxide, or an inert gas. Do not use oxygen or fuel gas.
Test Pressure. NFPA 54 requires a test pressure that is 1 ½ times the
maximum working pressure for the piping section, but not less than 3 psig.
For example, pipe supplying propane vapor to a second-stage or 2-PSI service
regulator may have a working pressure of 10 psig. In this situation, the test
pressure is at least 15 psig (1 ½ x 10). However, the second stage pipe supplying
propane to the appliances has an operating pressure of 11 inches water column.
In this situation, the test pressure is at least 3 psig, and appliances and their
controls are not connected to the piping system during the test.
Test Duration NFPA 54 and most state and local codes require a 10 minute
test duration for single-family dwellings and small capacity distribution systems
with less than 10 cubic feet (1,840 lineal feet of 1” steel pipe). However, if the
distribution piping is more than 10 cubic feet, NFPA 54, requires a test duration of
30 minutes for each 500 cubic feet of piping. Regardless of size, NFPA 54 states
that the duration of the test need not exceed 24 hours.
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page
2
NFPA 54 Regulations that Apply to Pressure Testing
Pressure Measuring Devices. NFPA 54,
7.1.4.1 requires: Test pressure shall be measured
with a pressure measuring device designed and
calibrated to read, record, or indicate a pressure
loss due to leakage during the pressure test period.
The source of pressure shall be isolated before the
pressure tests are made.
Mechanical gauges used to measure test
pressures shall have a range such that the highest
end of the scale is not greater than 5 times the test
pressure.
Figure 1. Test Gauges Installed
At Piping Connections at Two
2-PSI Piping Service Entrances
For example, a 0-15 psi gauge should be used for
a 3 psig pressure test, while a 0-75 psi gauge is
required for a 15 psig test.
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 3
Procedures Used to Pressure Test Propane Piping
Before testing, check the installation carefully to be sure it is properly
installed and meets applicable state and local codes and regulations.
•
All pipe, tubing, and fittings used in the installation must meet the requirements
in all applicable state and local codes and standards, particularly the National
Fuel Gas Code, NFPA 54.
•
For new installations, the underground lines and the lines inside buildings must
be left uncovered for the duration of the pressure testing.
•
All aboveground lines must be properly supported as necessary, and protected
from physical damage.
•
Before beginning a test, be sure the gauge(s) and test fittings are in good
condition. Test fittings equipped with Schrader valves should be fitted with
appropriate sealing caps and cap gaskets.
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 4
Procedures Used to Pressure Test Propane Piping
Pressure Testing Integral Two-Stage Distribution Systems: 11 Inches
Water Column Operating Pressure— Integral 2-Stage Regulator
Description
Test Pressure
Minimum Test
Duration
Before
appliances are
connected
3 psig minimum
10 minutes
Test Medium
Air, nitrogen, or
carbon dioxide
Pressure
Measuring
Device
A pressure gauge
designed and
calibrated to read,
record, or indicate
a pressure loss
due to leakage
during the
pressure test
period.
Figure 2. Pressure Testing Integral Two-Stage Distribution
Lines Operating Pressure: 11 Inches Water Column
This method is intended for testing the main and branch lines before they are connected
to the appliance shutoff valves and the integral two-stage regulator. The piping system
must withstand a test pressure of at least 3 psig for a minimum of 10 minutes without
showing any drop in pressure.
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 4
Procedures Used to Pressure Test Propane Piping
Figure 3. Example of Integral Two-Stage Piping Diagram
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 5
Procedures Used to Pressure Test Propane Piping
Step 1:
Make sure the entire line is disconnected from the propane
storage container regulator and the ends of all branch lines
are either capped or plugged.
Step 2:
Install a test adaptor and suitable gauge at any connection
in the piping system.
Step 3:
Install in the piping system a pressure-measuring device
designed and calibrated to read, record, or indicate a
pressure loss caused by leakage.
Step 4:
Pressurize the piping system to at least 3 psig. A hand
pump may be used, as illustrated in Figure 4. The source
of pressure shall be isolated before the pressure test is
made.
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page
5
Procedures Used to Pressure Test Propane Piping
Step 5:
Ensure the pressure on the piping system being pressure
tested remains constant for a minimum time period of 10
minutes.
Step 6:
If the piping system holds the test pressure for a minimum
of 10 minutes without any drop, the piping system is
considered gastight. (If the piping system is not
considered gastight, take appropriate action to locate the
leak and make necessary repairs.)
Step 7:
Prepare a record that indicates which portions of the piping
system were pressure-tested.
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page
5
Procedures Used to Pressure Test Propane Piping
Pressure Testing Two-Stage Distribution Systems: 11 Inches Water
Column Final Delivery Pressure— 1st & 2nd Stage Regulators
Description
Test Pressure
Buried
Distribution Line
(before regulator
is installed).
Not less than 1.5
(1½) times the
maximum working
pressure of the first
stage line. The
typical working
pressure of the first
stage regulator is
10 psig; therefore,
the test pressure
should be at least
15 psig.
Second Stage
Line, Before
appliances are
installed.
3 psig minimum
Minimum Test
Duration
Test Medium
10 minutes
Air, nitrogen, or
carbon dioxide
10 minutes
Air, nitrogen, or
carbon dioxide
Pressure
Measuring
Device
A pressure gauge
designed and
calibrated to
read, record, or
indicate a
pressure loss due
to leakage during
the pressure test
period.
Figure 5. Pressure Testing Two Stage Distribution Lines
Appliance Operating Pressure: 11" w.c.
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 6
Procedures Used to Pressure Test Propane Piping
Figure 6. Pressure Testing First-Stage Line
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 7
Procedures Used to Pressure Test Propane Piping
Step 1:
Disconnect the line from the storage container regulator
and the second-stage regulator.
Step 2:
Plug or cap the terminating ends of the first-stage line.
Step 3:
Install a pressure-measuring device designed and
calibrated to read, record, or indicate a pressure loss due
to leakage during the pressure test period in the container
end of the line.
Figure 7. Installing Test Gauge and Fittings
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 7
Procedures Used to Pressure Test Propane Piping
Step 4:
Pressurize the piping system to at least 15 psig. (An air
pump may be used, as illustrated in Figure 6.) Then
isolate the source of pressure.
Step 5:
Ensure the pressure remains constant for a minimum time
period of 10 minutes.
Step 6:
If the line holds the test pressure without any drop, the line
is considered gastight. (If the line is not considered
gastight, take appropriate action to locate the leak and
make necessary repairs.)
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 8
Procedures Used to Pressure Test Propane Piping
Step 7:
Prepare a record indicating the section(s) of pipe tested.
Figure 8. Recording the Pressure Test
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 8
Procedures Used to Pressure Test Propane Piping
Test the second-stage line(s) by using the same basic method used for
integral two-stage systems (a minimum 3-psig test for 10 minutes).
F
irs
tS
tage
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egulator
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ressure
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auge
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erviceV
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heckor
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ontainer
Figure 9. Pressure Testing Distribution Lines
Downstream of 2nd-Stage Regulator
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 9
D
is
connected
Procedures Used to Pressure Test Propane Piping
Pressure Testing 2-Pound Distribution Systems: 10 psig buried distribution line
pressure and 2-psi delivery pressure to one or more line regulators controlling 11
inches water column final delivery pressure. If the system uses a first-stage and
2-PSI service regulators connected by a buried distribution line, the system is tested as
a two-stage piping system (Figure 10).
First-Stage
Regulator
(10 psig outlet pressure)
Buried PE Tubing
Water Heate
Figure 10.
2-psi Service
Regulator
(2 psi g outl et pressure)
Furnace
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 9
R
Line Regulator Manifold
Procedures Used to Pressure Test Propane Piping
Minimum Test
Duration
Test Medium
10 minutes
Air, nitrogen, or
carbon dioxide
3 psig minimum
10 minutes
Air, nitrogen, or
carbon dioxide
3 psig minimum
10 minutes
Air, nitrogen, or
carbon dioxide
Description
Test Pressure
Buried
Distribution Line
(before regulator
is installed).
Not less than 1.5
(1½) times the
maximum working
pressure of the first
stage line. The
typical working
pressure of the first
stage regulator is 10
psig; therefore, the
test pressure should
be at least 15 psig.
Line Connecting
2-PSI Service
Regulator to
Distribution
Manifold.
Distribution Manfold and
distribution lines
to appliances
4.2.19 Student Book  © 2004 Propane Education & Research Council
Pressure
Measuring
Device
A pressure gauge
designed and
calibrated to
read, record, or
indicate a
pressure loss due
to leakage during
the pressure test
period.
Page 10
Procedures Used to Pressure Test Propane Piping
First-S
tage
R
egulator
A
irV
alve-E
quipped
Test Fittingw
ith
0to60psi Gauge
2-P
S
IS
ervice
R
egulator
P
ipe
C
ap
Figure 12. Pressure Testing First-Stage Line
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 11
Procedures Used to Pressure Test Propane Piping
Step 1:
Disconnect the line from the storage container regulator
and the second-stage regulator.
Step 2:
Plug or cap the terminating ends of the first-stage line.
Step 3:
Install a pressure-measuring device designed and
calibrated to read, record, or indicate a pressure loss due
to leakage during the pressure test period in the container
end of the line.
Step 4:
Pressurize the piping system to at least 15 psig. Then
isolate the source of pressure.
Step 5:
Ensure the pressure remains constant for a minimum time
period of 10 minutes.
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 11
Procedures Used to Pressure Test Propane Piping
Step 6:
If the line holds the test pressure without any drop, the line
is considered gastight. (If the line is not considered
gastight, take appropriate action to locate the leak and
make necessary repairs. Repeat the pressure test as
needed until a gastight condition is maintained.)
Step 7:
Prepare a record indicating the section(s) of pipe tested.
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 11
Procedures Used to Pressure Test Propane Piping
To test lines in a 2-psi system that uses a single line regulator and
distribution manifold:
Step 1:
Remove the line regulator located upstream of the distribution
manifold and replace with a pipe nipple. (Figure 13) Verify
that all valves at the manifold are manufacturer approved for
the pressure that will be used for the test and that the valves
are in their open positions.
Figure 13a. Line Regulator
and Manifold
Figure 13b. Line Regulator
Replaced with Pipe Nipple
for Pressure Test
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 11
Procedures Used to Pressure Test Propane Piping
Step 2:
Plug or cap the terminating ends of the lines at appliance
locations.
Step 3:
Install a pressure-measuring device designed and calibrated
to read, record, or indicate a pressure loss due to leakage
during the pressure test period in the outside connection
where the 2-PSI service regulator is disconnected for the
pressure test.
Step 4:
Pressurize the piping system to at least 3 psig. Then isolate
the source of pressure.
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 12
Procedures Used to Pressure Test Propane Piping
Step 5:
Ensure the pressure remains constant for a minimum time
period of 10 minutes.
Step 6:
If the line holds the test pressure without any drop, the lines
and manifold are considered gastight. (If the lines are not
considered gastight, take appropriate action to locate the leak
and make necessary repairs. Repeat the pressure test as
needed until a gastight condition is maintained.)
Step 7:
Prepare a record indicating the section(s) of pipe tested.
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 12
Procedures Used to Pressure Test Propane Piping
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Figure 14. 2-PSI System
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4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 13
Procedures Used to Pressure Test Propane Piping
Water Heater
Furnace
3 6 ,0 0 0 Btu h
8 0 ,0 0 0 Btu h
2-psi Service
Regulator
Dryer
Line
Re g u l a to r
2 8 ,0 0 0 B
R
Manifold
Range
A = 2 0 fe e t
5 2 ,0 0 0 Btu
B = 4 0 fe e t
Furnace
6 0 ,0 0 0 Btu h
Water Heat
Figure 15. CSST Multiple
R
Manifold System
Manifold
3 6 ,0 0 0 Bt
Line
Re g u l a to r
Fireplace
4 5 ,0 0 0Council
Btu h
4.2.19 Student Book  © 2004 Propane Education & Research
Page 13
Procedures Used to Pressure Test Propane Piping
Be sure to comply with your company’s pressure testing
procedures, along with code requirements of jurisdictional
authorities in your area. Also read and follow manufacturer
recommendations for pressure testing corrugated stainless
steel tubing as appropriate.
4.2.19 Student Book  © 2004 Propane Education & Research Council
Page 13
Time to See If You Got the Key Points of
This Module…
• Complete the Review on page 14.
• See if you are ready for the Certification
Exam by checking off the
performance criteria on page 15.
4.2.19 Student Book  © 2004 Propane Education & Research Council
Pages 14 & 15