CRC · California Residential Code
Fuel-gas piping test, pressure and leak-check procedure (manufactured homes & general)
If you own or install a manufactured home, the code requires you to test the home's gas piping with air at 10 to 14 inches water column, hold that isolated pressure for at least 10 minutes with no perceptible leak, then open appliance valves and test connections with non‑corrosive soapy solution; do not overpressurize the system (§ E404.5, § E404.5.1, § E404.5.2) .
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
For manufactured homes, the fuel-gas piping must be tested only with air at a pressure between 10 inches water column and 14 inches water column with all appliance shutoff valves closed, and the system must hold that pressure for not less than 10 minutes with no perceptible leakage (see § E404.5 and § E404.5.1). After a satisfactory pressure test, appliance valves are opened and appliance connectors (and the manufactured-home supply connector after installation) are tested with a non‑corrosive soapy/bubble solution; a warning must be provided not to overpressurize the system (see § E404.5.1 and § E404.5.2) .
The single most important rule: for manufactured homes, test the manufactured-home gas piping with air at 10–14 in. water column and hold the isolated pressure for at least 10 minutes with no perceptible leakage (§ E404.5 / § E404.5.1) .
Requirements in detail
Scope / test medium (manufactured homes)
- Test medium: air only for manufactured-home piping prior to connection to the site gas supply. See § E404.5 .
Test pressure & hold time (manufactured homes)
- Test pressure: not less than 10 inches water column and not more than 14 inches water column (that is ≈ 2.5–3.5 kPa). See § E404.5.1 .
- Duration: maintain the isolated pressure for not less than 10 minutes without perceptible leakage. See § E404.5.1 .
Leak-detection procedure (manufactured homes)
- Perform the pressure test with all appliance shutoff valves closed. See § E404.5 .
- After a satisfactory pressure test, open appliance valves and test gas appliance connectors with soapy water or bubble solution while the piping remains under the system pressure. Solutions must not contain corrosive chemicals. See § E404.5.1 .
- After the manufactured-home gas supply connector is installed, test its connections with the same non‑corrosive soapy/bubble solution. See § E404.5.1 .
Pressure measurement & instruments
- Pressure may be measured with a manometer, slope gauge, or gauge calibrated in inches of water or psi (kPa).
- Required gauge increments: 1/10 inch (≈ 2.5 mm) of water or 1/10 psi (≈ 0.7 kPa) increments, as applicable, for the accuracy needed in low‑pressure tests. See § E404.5.1 and related gauge requirements in inspection/test gauge provisions .
Decision-relevant dimensions / values
| Item | Required value / range | Code Reference |
|---|---|---|
| Manufactured-home test medium | Air only | § E404.5 |
| Manufactured-home test pressure | 10 in. wc to 14 in. wc (2.5–3.5 kPa) | § E404.5.1 |
| Hold time for manufactured-home test | Not less than 10 minutes without perceptible leakage | § E404.5.1 |
| Leak-detection fluid | Soapy/bubble solution — non‑corrosive | § E404.5.1 |
| Gauge increments for low-pressure tests | 1/10 inch (water) or 1/10 psi | § E404.5.1 |
| Warning about overpressurization | Installer warning required — do not overpressurize | § E404.5.2 |
How this compares to general (non‑manufactured) piping tests
- General fuel‑gas piping test requirements in the California Plumbing/Mechanical provisions call for higher test pressures (for example, a common requirement is not less than 10 psi (69 kPa) gauge for many piping tests) and longer minimum durations for some higher‑pressure systems — see § 1213.3 (Plumbing) / § 1313.3 (Mechanical) for the general test-pressure framework and test‑media options (air, CO2, nitrogen, inert gas) . Use the manufactured‑home E404 provisions when the installation is a manufactured home; use the general plumbing/mechanical sections for other systems.
Exceptions & special cases
- If an appliance or equipment is connected that is designed for operating pressures less than the test pressure, those appliances must be isolated from the piping system (by disconnecting and capping outlets) before performing a higher‑pressure test — see § 1213.2.4 (general piping test prep) .
- The manufactured-home rule is explicit about the test medium: only air is permitted for the manufactured-home fuel‑gas piping before connection to the supply (no inert gas alternatives are authorized in § E404.5) .
- For general (non-manufactured) systems, the test medium may include air, CO2, or nitrogen and test pressures are higher (see § 1213.3 / § 1313.3) — do not substitute those general rules for manufactured‑home testing unless the installation is covered by those general sections .
Common mistakes
- Overpressurizing the manufactured‑home system (exceeding 14 in. wc) — the code explicitly warns against overpressurization because it can damage valves, regulators, and appliances (§ E404.5.2) .
- Testing manufactured‑home piping with anything other than air, or later trying to pressure the system with the site gas before the required air test — both violate § E404.5 .
- Failing to close all appliance shutoff valves during the pressure test (the code requires them closed) or failing to isolate appliances that cannot tolerate the test pressure — see § E404.5 and general prep rules in § 1213.2.4 .
- Using a corrosive leak-detection fluid (the code requires non‑corrosive solutions) or using a gauge with insufficient graduation to detect small pressure changes — see § E404.5.1 and test‑gauge increments guidance .
- Neglecting to test the manufactured‑home supply connector after installation as required in § E404.5.1 .
Worked example — concrete scenario
Scenario: A manufactured home’s internal fuel‑gas piping has been installed and capped; appliance shutoffs are in place. The installer will perform the required manufactured‑home test.
- Set the test source to 12 inches water column (mid‑range between 10 and 14 in. wc) and isolate the manufactured‑home piping from the pressure source so the manufactured‑home piping is under the desired test pressure. (Requirement: § E404.5 / § E404.5.1) .
- Verify all appliance shutoff valves are closed. Start the timing and confirm the pressure holds for at least 10 minutes with no perceptible leakage. (Requirement: § E404.5.1) .
- If the pressure holds, open each appliance shutoff valve and spray the appliance connector fittings and the appliance inlet connection with a non‑corrosive soapy/bubble solution while the remainder of the piping remains under the pressure left in the system. Look for bubbles to indicate leaks. (Requirement: § E404.5.1) .
- After satisfactory connector checks, install the manufactured‑home gas supply connector and test its connections with soapy solution as required. (Requirement: § E404.5.1) .
- Do not exceed 14 in. wc at any time — the required installer warning about overpressurization must be heeded (§ E404.5.2). If leakage is found at any step, repair and retest until the system meets the code requirements. .
Related provisions
- § E404.5 — Fuel Gas Piping Test (manufactured homes)
- § E404.5.1 — Procedures for the manufactured‑home fuel‑gas piping test (pressures, duration, leak detection, gauges)
- § E404.5.2 — Installer warning: do not overpressurize the fuel gas piping system
- § 1213.2.4 — Isolation of appliances designed for operating pressures less than the test pressure (general piping prep)
- § 1213.3 / § 1313.3 — General fuel‑gas piping test pressures, acceptable test media, and test durations for non‑manufactured piping systems (Plumbing / Mechanical)
- § 1303.3.3.x — Test gauge graduation requirements for various test-pressure ranges (Mechanical inspection/test gauges)
Code references
Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:
CRC § 404.3 High relevance — show source text
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APPENDIX E
E 404.3 Mechanical Protection. All gas outlet risers, regulators, meters, valves, and other exposed equipment shall be protected against accidental damage. [NFPA 501A:4.4.3]
E 404.4 Special Rules on Atmospherically Con- trolled Regulators. Atmospherically controlled regulators shall be installed in such a manner that moisture cannot enter the regulator vent and accumulate above the diaphragm. Where the regulator vent is obstructed due to snow and icing conditions, shields, hoods, or other suitable devices shall be provided to guard against closing of the vent opening. [NFPA 501A:4.4.4.1 – 4.4.4.2]
E 404.5 Fuel Gas Piping Test. The manufactured home fuel gas piping system shall be tested only with air before it is connected to the gas supply. The manufactured home gas piping system shall be subjected to a pressure test with all appliance shutoff valves in their closed positions. [NFPA 501A:4.4.5]
E 404.5.1 Procedures. The fuel gas piping test shall consist of air pressure at not less than 10 inches water column or more than 14 inches water column (2.5 kPa to 3.5 kPa). The fuel gas piping system shall be isolated from the air pressure source and shall maintain this pressure for not less than 10 minutes without perceptible leakage. Upon satisfactory completion of the fuel gas piping test, the appliance valves shall be opened, and the gas appliance connectors shall be tested with soapy water or bubble solution while under the pressure remaining in the piping system. Solutions used for testing for leakage shall not contain corrosive chemicals. Pressure shall be measured with a manometer, slope gauge, or gauge that is calibrated in either water inch (mm) or psi (kPa) with increments of either [1] ⁄ 10 inch (2.5 mm) or [1] ⁄ 10 psi (0.7 kPa) gauge, as applicable. Upon satisfactory completion of the fuel gas piping test, the manufactured home gas supply connector shall be installed, and the connections shall be tested with soapy water or bubble solution. [NFPA 501A:4.4.5.1.1 – 4.4.5.1.6]
E 404.5.2 Warning. The following warning shall be supplied to the installer:
WARNING: Do not overpressurize the fuel gas piping system. Damage to valves, regulators, and appliances can occur due to pressurization beyond the maximums specified. [NFPA 501A:4.4.5.2]
E 404.5.3 Vents. Gas appliance vents shall be visually inspected to ensure that they have not been dislodged in transit and are connected securely to the appliance.
[NFPA 501A:4.4.5.3]
E 404.6 Oil Tanks. Oil tank capacities shall comply with the following:
(1) No more than one 660 gallon (2498 L) tank or two tanks with an aggregate capacity of 660 gallons (2498 L) or less shall be connected to one oil-burning appliance.
CRC § 8.1.1.6 High relevance — show source text
[NFPA 54:8.1.1.6] 1213.1.6 Test Medium. The test medium shall be air, nitrogen, carbon dioxide, or an inert gas. Oxygen shall not be used as a test medium. [NFPA 54:8.1.2] 1213.2 Test Preparation. Test preparation shall comply with Section 1213.2.1 through Section 1213.2.6. 1213.2.1 Pipe Joints. Pipe joints, including welds, shall be left exposed for examination during the test. Exception: Covered or concealed pipe end joints that have been previously tested in accordance with this code.
[NFPA 54:8.1.3.1] 1213.2.2 Expansion Joints. Expansion joints shall be provided with temporary restraints, if required, for the additional thrust load under test. [NFPA 54:8.1.3.2] 1213.2.3 Appliances and Equipment. Appliances and equipment that are not to be included in the test shall be either disconnected from the piping or isolated by blanks, blind flanges, or caps. Flanged joints at which blinds are inserted to blank off other equipment during the test shall not be required to be tested. [NFPA 54:8.1.3.3] 1213.2.4 Designed for Operating Pressures Less Than Test Pressure. Where the piping system is connected to appliances or equipment designed for operating pressures of less than the test pressure, such appliances or equipment shall be isolated from the piping system by disconnecting them and capping the outlet(s). [NFPA 54:8.1.3.4] 1213.2.5 Designed for Operating Pressures Equal to or Greater Than Test Pressure. Where the piping system is connected to appliances or equipment designed
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FUEL GAS PIPING
for operating pressures equal to or greater than the test pressure, such appliances or equipment shall be isolated from the piping system by closing the individual appliance or equipment shutoff valve(s). [NFPA 54:8.1.3.5]
1213.2.6 Safety. All testing of piping systems shall be performed in a manner that protects the safety of employees and the public during the test. [NFPA 54:8.1.3.6]
1213.3 Test Pressure. This inspection shall include an air, CO 2, or nitrogen pressure test, at which time the gas piping shall stand a pressure of not less than 10 psi (69 kPa) gauge pressure. Test pressures shall be held for a length of time satisfactory to the Authority Having Jurisdiction but in no case less than 15 minutes with no perceptible drop in pressure. For welded piping, and for piping carrying gas at pressures in excess of 14 inches water column pressure (3.5 kPa), the test pressure shall be not less than 60 psi (414 kPa) and shall be continued for a length of time satisfactory to the Authority Having Jurisdiction, but in no case for less than 30 minutes. For CSST carrying gas at pressures in excess of 14 inches water column (3.5 kPa) pressure, the test pressure shall be not less than 30 psi (207 kPa) for 30 minutes.
CRC § 1313.2.5 High relevance — show source text
1313.2.5 Designed for Operating Pressures Equal to or Greater than Test Pressure. Where the piping system is connected to appliances or equipment designed for operating pressures equal to or greater than the test pressure, such appliances or equipment shall be isolated from the piping system by closing the individual appliance or equipment shutoff valve(s). [NFPA 54:8.1.3.5] 1313.2.6 Safety. All testing of piping systems shall be performed in a manner that protects the safety of employees and the public during the test. [NFPA 54:8.1.3.6]
1313.3 Test Pressure. This inspection shall include an air, CO2, or nitrogen pressure test, at which time the gas piping shall stand a pressure of not less than 10 psi (69 kPa) gauge pressure. Test pressures shall be held for a length of time satisfactory to the Authority Having Jurisdiction but in no case less than 15 minutes with no perceptible drop in pressure. For welded piping, and for piping carrying gas at pressures in excess of 14 inches water column (3.5 kPa) pressure, the test pressure shall be not less than 60 psi (414 kPa) and shall be continued for a length of time satisfactory to the Authority Having Jurisdiction, but in no case for less than 30 minutes.
For CSST carrying gas at pressures in excess of 14 inches water column (3.5 kPa) pressure, the test pressure shall be 30 psi (207 kPa) for 30 minutes. These tests shall be made using air, CO2, or nitrogen pressure and shall be made in the presence of the Authority Having Jurisdiction. Necessary apparatus for conducting tests shall be furnished by the permit holder. Test gauges used in conducting test shall be in accordance with Section 1303.3.3.1 through Section 1303.3.3.4. 1313.4 Detection of Leaks and Defects. The piping system shall withstand the test pressure specified without showing any evidence of leakage or other defects. Any reduction of test pressures as indicated by pressure gauges shall be deemed to indicate the presence of a leak unless such reduction can be readily attributed to some other cause. [NFPA 54:8.1.5.1] 1313.4.1 Detecting Leaks. The leakage shall be located by means of an approved gas detector, a noncorrosive leak detection fluid, or other approved leak detection methods. [NFPA 54:8.1.5.2] 1313.4.2 Repair or Replace. Where leakage or other defects are located, the affected portion of the piping system shall be repaired or replaced and retested. [NFPA 54:8.1.5.3] 1313.5 Piping System Leak Test. Leak checks using fuel gas shall be permitted in piping systems that have been pressure-tested in accordance with Section 1313.0 through Section 1313.4.2. [NFPA 54:8.2.1] 1313.5.1 Turning Gas On. During the process of turning gas on into a system of new gas piping, the entire system shall be inspected to determine that there are no open fittings or ends and that all valves at unused outlets are closed and plugged or capped. [NFPA 54:8.2.2] **1313.5.2 Leak Check.
CRC § 113.3 High relevance — show source text
D 113.3 Mechanical Protection. All gas outlet risers, regulators, meters, valves, and other exposed equipment shall be protected against accidental damage. [NFPA 501A:4.4.3]
D 113.4 Special Rules on Atmospherically Con- trolled Regulators. Atmospherically controlled regulators shall be installed in such a manner that moisture cannot enter the regulator vent and accumulate above the diaphragm. Where the regulator vent is obstructed due to snow and icing conditions, shields, hoods, or other suitable devices shall be provided to guard against closing of the vent opening. [NFPA 501A:4.4.4.1 – 4.4.4.2]
D 113.5 Fuel Gas Piping Test. The manufactured home fuel gas piping system shall be tested only with air before it is connected to the gas supply. The manufactured home gas piping system shall be subjected to a pressure test with all appliance shutoff valves in their closed positions. [NFPA 501A:4.4.5]
D 113.5.1 Procedures. The fuel gas piping test shall consist of air pressure at not less than 10 inches water column or more than 14 inches water column (2.5 kPa to 3.5 kPa). The fuel gas piping system shall be isolated from the air pressure source and shall maintain this pressure for not less than 10 minutes without perceptible leakage. Upon satisfactory completion of the fuel gas piping test, the appliance valves shall be opened and the gas appliance connectors shall be tested with soapy water or bubble solution while under the pressure remaining in the piping system. Solutions used for testing for leakage shall not contain corrosive chemicals. Pressure shall be measured with a manometer, slope gauge, or gauge that is calibrated in either water inch (mm) or psi (kPa) with increments of either [1] ⁄ 10 of an inch (2.5 mm) or [1] ⁄ 10 psi (0.7 kPa) gauge, as applicable. Upon satisfactory completion of the fuel gas piping test, the manufactured home gas supply connector shall be installed and the connections shall be tested with soapy water or bubble solution.
[NFPA 501A:4.4.5.1.1 – 4.4.5.1.6]
D 113.5.2 Warning. The following warning shall be supplied to the installer:
WARNING: Do not overpressurize the fuel gas piping system. Damage to valves, regulators, and appliances can occur due to pressurization beyond the maximums specified. [NFPA 501A:4.4.5.2]
D 113.5.3 Vents. Gas appliance vents shall be visually inspected to ensure that they have not been dislodged in transit and are connected securely to the appliance.
[NFPA 501A:4.4.5.3]
D 113.6 Oil Tanks. Oil tank capacities shall comply with the following:
(1) No more than one 660 gallon (2498 L) tank or two tanks with an aggregate capacity of 660 gallons (2498 L) or less shall be connected to one oil-burning appliance.
(2) Two supply tanks, where used, shall be cross-connected and provided with a single fill and single vent, as described in NFPA 31 and shall be on a common slab and rigidly secured, one to the other.
CRC § 403.13 High relevance — show source text
(a) Where the distribution system is supplied from a gravity tank and the maximum hydrostatic head of oil in the tank is such that the oil pressure at the appliance inlet will not exceed a gauge pressure of 8 psig (55 kPa).
(b) Where a means is provided to automatically shut off the oil supply if the pressure-regulating device provided in accordance with Section E 403.13(8) fails to regulate the pressure as required.
(10)Only appliances equipped with primary safety controls specifically listed for the appliance shall be connected to a centralized oil distribution system. [NFPA 31:9.2.10 – 9.2.15]
E 404.0 Fuel Supply Systems Installation.
E 404.1 Flexible Gas Connector. Except for manufactured homes located on an all-weather wood, concrete, or concrete block foundation system or on a foundation constructed in accordance with the local building code or, in the absence of a local code, with a recognized model building code, each gas supply connector shall be listed for outside manufactured home use, shall be not more than 6 feet (1829 mm) in length, and shall have a capacity rating to supply the connected load.
[NFPA 501A:4.4.1]
E 404.2 Use of Approved Pipe and Fittings of Exten- sion. Where it is necessary to extend a manufactured home inlet to permit connection of the 6 foot (1829 mm) listed connector to the site gas outlet, the extension shall be of approved materials of the same size as the manufactured home inlet and shall be adequately supported at no more than 4 foot (1219 mm) intervals to the manufactured home. [NFPA 501A:4.4.2]
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APPENDIX E
E 404.3 Mechanical Protection. All gas outlet risers, regulators, meters, valves, and other exposed equipment shall be protected against accidental damage. [NFPA 501A:4.4.3]
E 404.4 Special Rules on Atmospherically Con- trolled Regulators. Atmospherically controlled regulators shall be installed in such a manner that moisture cannot enter the regulator vent and accumulate above the diaphragm. Where the regulator vent is obstructed due to snow and icing conditions, shields, hoods, or other suitable devices shall be provided to guard against closing of the vent opening. [NFPA 501A:4.4.4.1 – 4.4.4.2]
E 404.5 Fuel Gas Piping Test. The manufactured home fuel gas piping system shall be tested only with air before it is connected to the gas supply. The manufactured home gas piping system shall be subjected to a pressure test with all appliance shutoff valves in their closed positions. [NFPA 501A:4.4.5]
E 404.5.1 Procedures. The fuel gas piping test shall consist of air pressure at not less than 10 inches water column or more than 14 inches water column (2.5 kPa to 3.5 kPa). The fuel gas piping system shall be isolated from the air pressure source and shall maintain this pressure for not less than 10 minutes without perceptible leakage.
CRC § 1324.5.1.1 High relevance — show source text
1324.5.1.1 Required Test Pressure. The test pressure for pressure gases and vacuum systems shall be 1.5 times the system operating pressure but not less than a gauge pressure of 150 psi (1034 kPa). The test pressure shall be maintained until each joint has been examined for leakage by means of a leak detectant that is safe for use with oxygen and does not contain ammonia. [NFPA 99:5.1.12.2.3.4, 5.1.12.2.3.5]
1324.5.1.2 Leaks. Leaks, if any, shall be located, repaired (if permitted), replaced (if required), and retested. [NFPA 99:5.1.12.2.3.6]
1324.5.2 Initial Cross-Connection Test. It shall be
determined that no cross-connections exist between the
various medical gas and vacuum piping systems. [NFPA 99:5.1.12.2.4]
1324.5.2.1 Atmospheric Pressure. All piping systems shall be reduced to atmospheric pressure.
[NFPA 99:5.1.12.2.4.1]
1324.5.2.2 Sources of Test Gas. Sources of test
gas shall be disconnected from all piping systems, except for the one system being tested. [NFPA 99:5.1.12.2.4.2]
1324.5.2.3 System to Be Charged. The system under test shall be charged with oil-free, dry nitrogen NF to a gauge pressure of 50 psi (345 kPa).
[NFPA 99:5.1.12.2.4.3]
1324.5.2.4 Check Outlets and Inlets. After the
installation of the individual faceplates with appropriate adapters matching outlet/inlet labels, each individual outlet/inlet in each installed medical gas and vacuum piping system shall be checked to determine that the test gas is being dispensed only from the piping system being tested. [NFPA 99:5.1.12.2.4.4]
1324.5.2.5 Repeat Test. The cross-connection test referenced in Section 1324.5.2 shall be repeated for each installed medical gas and vacuum piping system. [NFPA 99:5.1.12.2.4.5]
1324.5.2.6 Identification of System. The proper labeling and identification of system outlets/inlets shall be confirmed during these tests. [NFPA 99:5.1.12.2.4.6]
1324.5.3 Initial Piping Purge Tests. The outlets in each medical gas piping system shall be purged to remove any particulate matter from the distribution piping. [NFPA 99:5.1.12.2.5]
1324.5.3.1 Procedure. Using appropriate adapters, each outlet shall be purged with an intermittent high-volume flow of test gas until the purge produces no discoloration in a clean white cloth.
[NFPA 99:5.1.12.2.5.1]
CRC § 8.1.3.5 High relevance — show source text
** Where the piping system is connected to appliances or equipment designed
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FUEL GAS PIPING
for operating pressures equal to or greater than the test pressure, such appliances or equipment shall be isolated from the piping system by closing the individual appliance or equipment shutoff valve(s). [NFPA 54:8.1.3.5]
1213.2.6 Safety. All testing of piping systems shall be performed in a manner that protects the safety of employees and the public during the test. [NFPA 54:8.1.3.6]
1213.3 Test Pressure. This inspection shall include an air, CO 2, or nitrogen pressure test, at which time the gas piping shall stand a pressure of not less than 10 psi (69 kPa) gauge pressure. Test pressures shall be held for a length of time satisfactory to the Authority Having Jurisdiction but in no case less than 15 minutes with no perceptible drop in pressure. For welded piping, and for piping carrying gas at pressures in excess of 14 inches water column pressure (3.5 kPa), the test pressure shall be not less than 60 psi (414 kPa) and shall be continued for a length of time satisfactory to the Authority Having Jurisdiction, but in no case for less than 30 minutes. For CSST carrying gas at pressures in excess of 14 inches water column (3.5 kPa) pressure, the test pressure shall be not less than 30 psi (207 kPa) for 30 minutes. These tests shall be made using air, CO 2, or nitrogen pressure and shall be made in the presence of the Authority Having Jurisdiction. Necessary apparatus for conducting tests shall be furnished by the permit holder. Test gauges used in conducting tests shall be in accordance with Section 318.0.
1213.4 Detection of Leaks and Defects. The piping system shall withstand the test pressure specified without showing any evidence of leakage or other defects. Any reduction of test pressures as indicated by pressure gauges shall be deemed to indicate the presence of a leak unless such reduction can be readily attributed to some other cause. [NFPA 54:8.1.5.1]
1213.4.1 Detecting Leaks. The leakage shall be located by means of an approved gas detector, a noncorrosive leak detection fluid, or other approved leak detection methods. [NFPA 54:8.1.5.2]
1213.4.2 Repair or Replace. Where leakage or other defects are located, the affected portion of the piping system shall be repaired or replaced and retested. [NFPA 54:8.1.5.3]
1213.5 Piping System Leak Test. Leak checks using fuel gas shall be permitted in piping systems that have been pressure-tested in accordance with Section 1213.0 through Section 1213.4.2. [NFPA 54:8.2.1]
1213.5.1 Turning Gas On. During the process of turning gas on into a system of new gas piping, the entire system shall be inspected to determine that there are no open fittings or ends and that all valves at unused outlets are closed and plugged or capped. [NFPA 54:8.2.2]
CRC § 318.0. High relevance — show source text
These tests shall be made using air, CO 2, or nitrogen pressure and shall be made in the presence of the Authority Having Jurisdiction. Necessary apparatus for conducting tests shall be furnished by the permit holder. Test gauges used in conducting tests shall be in accordance with Section 318.0.
1213.4 Detection of Leaks and Defects. The piping system shall withstand the test pressure specified without showing any evidence of leakage or other defects. Any reduction of test pressures as indicated by pressure gauges shall be deemed to indicate the presence of a leak unless such reduction can be readily attributed to some other cause. [NFPA 54:8.1.5.1]
1213.4.1 Detecting Leaks. The leakage shall be located by means of an approved gas detector, a noncorrosive leak detection fluid, or other approved leak detection methods. [NFPA 54:8.1.5.2]
1213.4.2 Repair or Replace. Where leakage or other defects are located, the affected portion of the piping system shall be repaired or replaced and retested. [NFPA 54:8.1.5.3]
1213.5 Piping System Leak Test. Leak checks using fuel gas shall be permitted in piping systems that have been pressure-tested in accordance with Section 1213.0 through Section 1213.4.2. [NFPA 54:8.2.1]
1213.5.1 Turning Gas On. During the process of turning gas on into a system of new gas piping, the entire system shall be inspected to determine that there are no open fittings or ends and that all valves at unused outlets are closed and plugged or capped. [NFPA 54:8.2.2]
1213.5.2 Leak Check. Immediately after the gas is turned on into a new system or into a system that has been initially restored after an interruption of service, the piping system shall be checked for leakage. Where leak
age is indicated, the gas supply shall be shut off until the necessary repairs have been made. [NFPA 54:8.2.3]
1213.5.3 Placing Appliances and Equipment in Operation. Appliances and equipment shall not be placed in operation until after the piping system has been checked for leakage in accordance with Section 1213.5.2, the piping system is purged in accordance with Section 1213.6, and connections to the appliance are checked for leakage. [NFPA 54:8.2.4]
1213.6 Purging Requirements. The purging of piping shall be in accordance with Section 1213.6.1 through Section 1213.6.3. [NFPA 54:8.3]
1213.6.1 Piping Systems Required to be Purged Outdoors. The purging of piping systems shall be in accordance with Section 1213.6.1.1 through Section 1213.6.1.5 where the piping system meets either of the following:
(1) The design operating gas pressure is greater than 2 psig (14 kPa).
(2) The piping being purged contains one or more sections of pipe or tubing meeting the size and length criteria of Table 1213.6.1. [NFPA 54:8.3.1]
TABLE 1213.6.1
SIZE AND LENGTH OF PIPING
CRC § 1303.3.3.1 High relevance — show source text
Necessary apparatus for conducting tests shall be furnished by the permit holder. Test gauges used in conducting test shall be in accordance with Section 1303.3.3.1 through Section 1303.3.3.4. 1313.4 Detection of Leaks and Defects. The piping system shall withstand the test pressure specified without showing any evidence of leakage or other defects. Any reduction of test pressures as indicated by pressure gauges shall be deemed to indicate the presence of a leak unless such reduction can be readily attributed to some other cause. [NFPA 54:8.1.5.1] 1313.4.1 Detecting Leaks. The leakage shall be located by means of an approved gas detector, a noncorrosive leak detection fluid, or other approved leak detection methods. [NFPA 54:8.1.5.2] 1313.4.2 Repair or Replace. Where leakage or other defects are located, the affected portion of the piping system shall be repaired or replaced and retested. [NFPA 54:8.1.5.3] 1313.5 Piping System Leak Test. Leak checks using fuel gas shall be permitted in piping systems that have been pressure-tested in accordance with Section 1313.0 through Section 1313.4.2. [NFPA 54:8.2.1] 1313.5.1 Turning Gas On. During the process of turning gas on into a system of new gas piping, the entire system shall be inspected to determine that there are no open fittings or ends and that all valves at unused outlets are closed and plugged or capped. [NFPA 54:8.2.2] 1313.5.2 Leak Check. Immediately after the gas is turned on into a new system or into a system that has been initially restored after an interruption of service, the piping system shall be checked for leakage. Where leakage is indicated, the gas supply shall be shut off until the necessary repairs have been made. [NFPA 54:8.2.3]
1313.5.3 Placing Appliances and Equipment in Operation. Appliances and equipment shall not be placed in operation until after the piping system has been checked for leakage in accordance with Section 1313.5.2, the piping system is purged in accordance with Section 1313.6, and connections to the appliance are checked for leakage. [NFPA 54:8.2.4]
1313.6 Purging Requirements. The purging of piping shall be in accordance with Section 1313.6.1 through Section 1313.6.3. [NFPA 54:8.3]
1313.6.1 Piping Systems Required to be Purged Outdoors. The purging of piping systems shall be in accordance with Section 1313.6.1.1 through Section 1313.6.1.4 where the piping system meets either of the following:
(1) The design operating gas pressure is greater than 2 psig (14 kPag).
(2) The piping being purged contains one or more sections of pipe or tubing meeting the size and length criteria of Table 1313.6.1. [NFPA 54:8.3.1]
292 2025 CALIFORNIA MECHANICAL CODE
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CRC § 25270.2 High relevance — show source text
as described in Health and Safety Code Section 25270.2(o)(1)(C)(i)._ 3. Piping systems connected to a petroleum hazardous waste tank in an underground area that complies with the hazardous waste tank standards pursuant to the California Code of Regulations, Title 22, Chapter 15, Article 10 (commencing with Section 66265.190), and the facility has been issued a unified program facility permit pursu- ant to Health and Safety Code Section 25404.2 for generation, treatment, accumulation or storage of hazardous waste, as described in Health and Safety Code Section 25270.2(o)(1) (C)(ii).
5703.6.3 Testing. Unless tested in accordance with the applicable section of ASME B31.9, piping, before being covered, enclosed or placed in use, shall be hydrostatically tested to 150 percent of the maximum anticipated pressure of the system, or pneumatically tested to 110 percent of the maximum anticipated pressure of the system, but not less than 5 pounds per square inch gauge (psig) (34.47 kPa) at the highest point of the system. This test shall be maintained for a sufficient time period to complete visual inspection of joints and connections. For not less than 10 minutes, there shall be no leakage or permanent distortion. Care shall be exercised to ensure that these pressures are not applied to vented storage tanks. Such storage tanks shall be tested independently from the piping.
2025 CALIFORNIA FIRE CODE 57-7
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
FLAMMABLE AND COMBUSTIBLE LIQUIDS
5703.6.3.1 Existing piping. Existing piping shall be tested in accordance with this section where the fire code official has reasonable cause to believe that a leak exists. Piping that could contain flammable or combustible liquids shall not be tested pneumatically. Such tests shall be at the expense of the owner or operator.
Exception: Vapor-recovery piping is allowed to be tested using an inert gas.
5703.6.4 Protection from vehicles. Guard posts or other approved means shall be provided to protect piping, valves or fittings subject to vehicular damage in accordance with Section 312.
5703.6.5 Protection from external corrosion and galvanic action. Where subject to external corrosion, piping, related fluidhandling components and supports for both underground and above-ground applications shall be fabricated from noncorrosive materials, and coated or provided with corrosion protection. Dissimilar metallic parts that promote galvanic action shall not be joined.
5703.6.6 Valves. Piping systems shall contain a sufficient number of manual control valves and check valves to operate the system properly and to protect the plant under both normal and emergency conditions. Piping systems in connection with pumps shall contain a sufficient number of such valves to control properly the flow of liquids in normal operation and in the event of physical damage or fire exposure.
5703.6.6.1 Backflow protections. Connections to pipelines or piping by which equipment (such as tank cars, tank vehicles or marine vessels) discharges liquids into storage tanks shall be provided with check valves or block valves for automatic protection against backflow where the piping arrangement is such that backflow from the system is possible. Where loading and unloading is done through a common pipe system, a check valve is not required. However, a block valve, located in an area where it is provided with ready access or remotely operable, shall be provided.
CRC § 112.3 High relevance — show source text
(9) A device shall be provided that will automatically shut off the oil supply to the appliance if the oil pressure at the appliance inlet exceeds a gauge pressure of 8 psig (55 kPa). The device shall not be required under either of the following conditions:
(a) Where the distribution system is supplied from a gravity tank and the maximum hydrostatic head of oil in the tank is such that the oil pressure at the appliance inlet will not exceed a gauge pressure of 8 psig (55 kPa).
(b) Where a means is provided to automatically shut off the oil supply if the pressure-regulating device provided in accordance with Section D 112.3(8) fails to regulate the pressure as required.
(10) Only appliances equipped with primary safety controls specifically listed for the appliance shall be connected to a centralized oil distribution system. [NFPA 31:9.2.10 – 9.2.15]
2025 CALIFORNIA MECHANICAL CODE 407
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APPENDIX D
D 113.0 Fuel Supply Systems Installation.
D 113.1 Flexible Gas Connector. Except for manufactured homes located on an all-weather wood, concrete, or concrete block foundation system or on a foundation constructed in accordance with the local building code or, in the absence of a local code, with a recognized model building code, each gas supply connector shall be listed for outside manufactured home use, shall be not more than 6 feet (1829 mm) in length, and shall have a capacity rating to supply the connected load.
[NFPA 501A:4.4.1]
D 113.2 Use of Approved Pipe and Fittings of Exten- sion. Where it is necessary to extend a manufactured home inlet to permit connection of the 6 foot (1829 mm) listed connector to the site gas outlet, the extension shall be of approved materials of the same size as the manufactured home inlet and shall be adequately supported at no more than 4 foot (1219 mm) intervals to the manufactured home. [NFPA 501A:4.4.2]
D 113.3 Mechanical Protection. All gas outlet risers, regulators, meters, valves, and other exposed equipment shall be protected against accidental damage. [NFPA 501A:4.4.3]
D 113.4 Special Rules on Atmospherically Con- trolled Regulators. Atmospherically controlled regulators shall be installed in such a manner that moisture cannot enter the regulator vent and accumulate above the diaphragm. Where the regulator vent is obstructed due to snow and icing conditions, shields, hoods, or other suitable devices shall be provided to guard against closing of the vent opening. [NFPA 501A:4.4.4.1 – 4.4.4.2]
D 113.5 Fuel Gas Piping Test. The manufactured home fuel gas piping system shall be tested only with air before it is connected to the gas supply. The manufactured home gas piping system shall be subjected to a pressure test with all appliance shutoff valves in their closed positions. [NFPA 501A:4.4.5]
D 113.5.1 Procedures. The fuel gas piping test shall consist of air pressure at not less than 10 inches water column or more than 14 inches water column (2.5 kPa to 3.5 kPa).
CRC § 1213.0 High relevance — show source text
1213.0 Pressure Testing, Inspection, and Purging . . . . . . . . . . . . . . . . .231
1213.1 Piping Installations . . . . . . . . . . . .231
1213.2 Test Preparation . . . . . . . . . . . . . .231
1213.3 Test Pressure . . . . . . . . . . . . . . . .232
1213.4 Detection of Leaks and Defects . .232
1213.5 Piping System Leak Test . . . . . . .232
1213.6 Purging Requirements . . . . . . . . .232
Table 1213.6.1 Size and Length of Piping . . . . . .232
1214.0 Required Gas Supply . . . . . . . . . .233
1214.1 General . . . . . . . . . . . . . . . . . . . . .233
1214.2 Volume . . . . . . . . . . . . . . . . . . . . .233
1214.3 Gas Appliances . . . . . . . . . . . . . .233
1214.4 Size of Piping Outlets . . . . . . . . . .233
1215.0 Required Gas Piping Size . . . . . .234
1215.1 Pipe Sizing Methods . . . . . . . . . . .234
1215.2 Sizing of Gas Piping Systems . . .234
1215.3 Sizing Equations . . . . . . . . . . . . . .234
Table 1215.3 Cr and Y for Natural Gas
and Undiluted Propane at Standard Conditions . . . . . . . . . . .234
1215.4 Sizing of Piping Sections . . . . . . .234
1215.5 Engineering Methods . . . . . . . . . .235
1215.6 Variable Gas Pressure . . . . . . . . .235
Table 1215.2(1) Schedule 40 Metallic Pipe . . . . . .237
Table 1215.2(2) Schedule 40 Metallic Pipe . . . . . .238
Table 1215.2(3) Schedule 40 Metallic Pipe . . . . . .239
Table 1215.2(4) Schedule 40 Metallic Pipe . . . . . .240
Table 1215.2(5) Schedule 40 Metallic Pipe . . . . . .241
Table 1215.2(6) Schedule 40 Metallic Pipe . . . . . .242
Table 1215.2(7) Semi-Rigid Copper Tubing . . . . . .243
Table 1215.2(8) Semi-Rigid Copper Tubing . . . . . .244
Table 1215.2(9) Semi-Rigid Copper Tubing . . . . . .245
Table 1215.2(10) Semi-Rigid Copper Tubing . . . . . .246
Table 1215.2(11) Semi-Rigid Copper Tubing . . . . . .247
Table 1215.2(12) Semi-Rigid Copper Tubing . . . . . .248
Table 1215.2(13) Semi-Rigid Copper Tubing . . . . . .249
Table 1215.2(14) Corrugated Stainless Steel Tubing (CSST) . . . . . . . . . . . . . . .250
Frequently asked questions
Can I pressure-test a manufactured‑home gas system with nitrogen or CO2?
No. For manufactured homes the code requires the manufactured‑home fuel‑gas piping system be tested only with air before it is connected to the gas supply (see § E404.5) .
What pressure should I set for the manufactured‑home test?
Set the test pressure between 10 in. wc and 14 in. wc; keep the system isolated and maintain pressure for at least 10 minutes with no perceptible leak (§ E404.5.1) .
Do I need to test appliance connectors after the pressure test?
Yes. After the piping passes the pressure hold, open appliance valves and apply a non‑corrosive soapy/bubble solution to appliance connectors while the system is still under the remaining pressure, and test the manufactured‑home supply connector after installation (§ E404.5.1) .
What if the system needs a higher test pressure for other piping?
For general (non‑manufactured) piping, other sections (e.g., § 1213.3 / § 1313.3) specify higher test pressures and allow other test media (air, CO2, nitrogen). Do not apply those higher‑pressure procedures to manufactured‑home piping unless the installation falls under those general provisions .
What is the biggest risk to watch for during testing?
Overpressurization: the code explicitly warns that pressurizing beyond the specified maximums can damage valves, regulators, and appliances — do not exceed 14 in. wc for manufactured homes (§ E404.5.2) .
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