CPC · California Plumbing Code
Blowdown, purging, initial pressure tests and leak testing for new or altered systems
For homeowners: when medical gas piping is installed or altered (e.g., in a clinic), the contractor must first blow the lines clear with clean nitrogen, pressure‑test each section at a higher safety pressure (1.5× operating pressure but at least 150 psi), remove particles by purging, leak‑test final connections with the system gas, and keep permanent test records — all required by the California Plumbing Code (§ 1324.3, § 1324.4, § 1324.5, § 1324.5.8, § 1324.5.9) .
Last reviewed: July 6, 2026
What the code requires — plain English
Piping for medical gas and vacuum systems must be blown clear with oil‑free, dry nitrogen NF before installing outlets or other components (§ 1324.4) and every section must be pressure tested at specified times and pressures (§ 1324.5, § 1324.5.1.1) . After final tie‑in the new joint(s) must be leak‑tested with the system gas and vacuum joints require ultrasonic or equivalent detection; outlets downstream of a brazed connection must be purged and particle removal performed as required (§ 1324.5.8, § 1324.5.9) .
The single most important rule: blow the new piping clean with oil‑free, dry nitrogen before installing outlets, test each section at 1.5× operating pressure (but never less than 150 psi), locate and repair leaks, then purge and verify gas concentration before patient‑use (§ 1324.3, § 1324.4, § 1324.5.1.1) .
Requirements in detail
Key defined terms (bolded on first mention)
- Blowdown — blowing the distribution piping clear with gas prior to installing outlets or sensitive components (§ 1324.4) .
- Test gas — oil‑free, dry nitrogen NF required for blowdown and many tests (§ 1324.3) .
- Final tie‑in test — leak testing of the joints connecting new work to existing system using the system gas at normal operating pressure (§ 1324.5.9) .
- Heavy, intermittent purging — the particulate removal purging required after construction debris may be present (§ 1324.5.8) .
When tests/operations must be done
- Blowdown: after distribution piping is installed but before station outlet/inlet rough‑ins or other components are installed (§ 1324.4) .
- Initial pressure tests: for each piping section (1) after blowdown, (2) after station outlet/inlet rough‑ins, and (3) before installing components that would be damaged by test pressure (§ 1324.5) .
- Source shutoff: the source shutoff valve must remain closed during the pressure tests specified in § 1324.5 (§ 1324.5.1) .
- Cross‑connection check: confirm no cross‑connections; piping reduced to atmospheric pressure; test charging for this cross‑connection check to 50 psi with oil‑free, dry nitrogen NF (§ 1324.5.2, § 1324.5.2.1–.3) .
- Particulate removal: perform heavy, intermittent purging to remove construction particulates (§ 1324.5.8) .
- Final tie‑in leak test: use the gas of system designation at normal operating pressure and a leak detectant safe for oxygen and free of ammonia; vacuum joints require ultrasonic detection or equivalent (§ 1324.5.9 and subsections) .
- Records: permanent records of the final tie‑in tests must be maintained per NFPA 99 references in § 1324.5.9.4 .
Decision‑relevant values and actions (summary table)
| Decision / value | Required action or value | Code Reference |
|---|---|---|
| Test gas for blowdown and most tests | Oil‑free, dry nitrogen NF | § 1324.3 |
| When to perform blowdown | After distribution piping installation but before station outlet/inlet rough‑ins or other components | § 1324.4 |
| Timing for initial pressure tests | (1) After blowdown (2) After outlet/inlet rough‑ins (3) Before installing pressure‑sensitive components | § 1324.5 |
| Required test pressure (pressure gases & vacuum) | 1.5 × system operating pressure, but not less than 150 psi (1034 kPa); maintain while inspecting joints with safe leak detectant | § 1324.5.1.1 |
| Cross‑connection verification charge | Charge system under test to 50 psi (345 kPa) with oil‑free, dry nitrogen NF | § 1324.5.2.3 |
| Particulate removal | Heavy, intermittent purging of pipeline to remove construction deposits | § 1324.5.8 |
| Final tie‑in leak test (pressure gases) | Leak‑test joints with gas of system designation at normal operating pressure; use oxygen‑safe, ammonia‑free detectant | § 1324.5.9 |
| Vacuum joint testing method | Use ultrasonic leak detector or equivalent capable of detecting leaks in an active vacuum system | § 1324.5.9.1 |
Exceptions & special cases
- The code text we retrieved does not provide alternate test pressures or specific exceptions for very high‑pressure systems beyond the 1.5×/150‑psi rule; if your system operating pressure would make 1.5× exceed typical fitting ratings, consult the AHJ and NFPA 99 references cited in the sections (§ 1324.5.1.1) .
- Cryogenic central supply testing and specialized cryogenic procedures are addressed elsewhere (see referenced NFPA/ANSI standards); the CPC text we have points to specialized requirements for cryogenic systems but the detailed method is not reproduced in the retrieved snippets — consult § 1324.5.7.3 and the standards cited there for those specifics .
- The CPC requires testing and certification by a technically competent third party per § 1324.5.7; where in‑house personnel perform testing, they must meet the competency criteria in the code (§ 1324.5.7.2–.3) .
If you need a ruling about a very specific, unusual pressure or material condition, the code references (NFPA 99 and ASSE/IAPMO/ANSI standards cited in these sections) will be the next source; the retrieved CPC excerpts do not include the full NFPA test tables or cryogenic details.
Common mistakes
- Assuming atmospheric blowdown alone is sufficient — the CPC requires blowdown with oil‑free, dry nitrogen NF prior to installing outlets (§ 1324.4) .
- Testing at the system operating pressure only — the code requires 1.5× operating pressure, but not less than 150 psi for pressure tests (§ 1324.5.1.1) .
- Using a leak check fluid that is not safe for oxygen or that contains ammonia — the final tie‑in must use a detectant safe with oxygen and free of ammonia (§ 1324.5.9) .
- Forgetting to keep the source shutoff valve closed during the pressure test (§ 1324.5.1) .
- Failing to perform heavy, intermittent purging to remove particulates after construction — leaving particulate can cause downstream device problems and fails the requirement in § 1324.5.8 .
- Not documenting test results — permanent records for final tie‑in tests are required (§ 1324.5.9.4) .
Worked example — tie‑in of a new oxygen branch to an existing system
Scenario: You are connecting a new branch of oxygen piping to an existing Category‑1 medical oxygen system whose normal operating pressure is 50 psi.
Step 1 — Blowdown: After the new distribution piping is installed, blow the pipe clear with oil‑free, dry nitrogen NF before installing station outlets or other components, per § 1324.4 .
Step 2 — Initial pressure test: Compute required test pressure: 1.5 × operating pressure = 1.5 × 50 psi = 75 psi, but the code requires not less than 150 psi, so you must test at 150 psi gauge. Maintain that pressure while examining EVERY joint with an oxygen‑safe, ammonia‑free leak detectant (§ 1324.5.1.1) . Ensure the source shutoff valve is closed during this test (§ 1324.5.1) .
Step 3 — Cross‑connection test: When verifying no cross‑connections, reduce other systems to atmospheric and charge the system under test with oil‑free, dry nitrogen NF to 50 psi for that check, per § 1324.5.2.3 .
Step 4 — Particle purge and final tie‑in: After final brazed connection and successful leak test, perform heavy, intermittent purging downstream to remove particulates (per § 1324.5.8) and purge the outlet(s) immediately downstream of the tie‑in in accordance with § 1324.5.9.2; then perform final leak test with the system gas at normal operating pressure and keep records (§ 1324.5.8, § 1324.5.9) cite .
Step 5 — Operational verification: Before use for patient care, perform the operational pressure and gas concentration checks required by the following operational test sections (see § 1324.5.10 and § 1324.5.11) — these are referenced in the CPC and must be completed before putting the new branch into service .
Related provisions
- § 1324.3 — Test gas specification: oil‑free, dry nitrogen NF .
- § 1324.5.1.1 — Required test pressure (1.5× operating pressure; not less than 150 psi) .
- § 1324.5.2 — Initial cross‑connection test procedures and charging to 50 psi for that test .
- § 1324.5.7 — System verification testing competency and third‑party tester requirements .
- § 1324.5.10 — Operational flow/pressure drop tests at outlets/inlets .
- § 1324.5.11 — Medical gas concentration testing after purging (§ references gas‑specific concentration checks) .
Code references
Grounded in the retrieved California Plumbing Code — click a citation to read the verbatim passage:
CPC § 1324.4 High relevance — show source text
1324.4 Initial Piping Blowdown. Piping in medical gas and vacuum distribution systems shall be blown clear by means of oil-free, dry nitrogen NF after installation of the distribution piping but before installation of station outlet/inlet rough-in assemblies and other system components (e.g., pressure/vacuum alarm devices, pressure/vacuum indicators, pressure relief valves, manifolds, source equipment). [NFPA 99:5.1.12.2.2]
1324.5 Initial Pressure Tests – Medical Gas and Vac- uum Systems. Each section of the piping in medical gas and vacuum systems shall be pressure tested. Initial pressure tests shall be conducted as follows:
(1) After blowdown of the distribution piping.
(2) After installation of station outlet/inlet rough-in assemblies.
(3) Prior to the installation of components of the distribution piping system that would be damaged by the test pressure (e.g., pressure/vacuum alarm devices, pressure/vacuum indicators, line pressure relief valves). [NFPA 99:5.1.12.2.3.1, 5.1.12.2.3.2]
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HEALTH CARE FACILITIES AND MEDICAL GAS AND MEDICAL VACUUM SYSTEMS
1324.5.1 Shutoff Valve. The source shutoff valve shall
remain closed during tests specified in Section 1324.5 through Section 1324.5.1.2. [NFPA 99:5.1.12.2.3.3]
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]
CPC § 1324.0 High relevance — show source text
1324.0 Performance Criteria and Testing Category 1 (Gases, Medical Surgical Vacuum). 1324.1 Where Required. Inspection and testing shall be performed on components, or portions thereof, of new, piped medical gas or vacuum systems, additions, renovations, temporary installations, or repaired systems in accordance with Section 1324.2 through Section 1324.5.11, and certified in accordance with Section 1306.0.
1324.2 Breached Systems. All systems that are breached and components that are subject to additions, renovations, or replacement (e.g., new gas sources: bulk, manifolds, compressors, dryers, alarms) shall be inspected and tested. Systems shall be deemed breached at the point of pipeline intrusion by physical separation or by system component removal, replacement, or addition. Breached portions of the systems subject to inspection and testing shall be confined to only the specific altered zone and components in the immediate zone or area that is located upstream for vacuum systems and downstream for pressure gases at the point or area of intrusion. [NFPA 99:5.1.12.1.3 – 5.1.12.1.5]
1324.2.1 Reports. The inspection and testing reports shall be submitted directly to the party that contracted for the testing, who shall submit the report through channels to the responsible facility authority and any others that are required. Reports shall contain detailed listings of all findings and results. [NFPA 99:5.1.12.1.6, 5.1.12.1.7] 1324.3 Test Gas. The test gas shall be oil-free, dry nitrogen NF. [NFPA 99:5.1.12.2.1.2]
1324.4 Initial Piping Blowdown. Piping in medical gas and vacuum distribution systems shall be blown clear by means of oil-free, dry nitrogen NF after installation of the distribution piping but before installation of station outlet/inlet rough-in assemblies and other system components (e.g., pressure/vacuum alarm devices, pressure/vacuum indicators, pressure relief valves, manifolds, source equipment). [NFPA 99:5.1.12.2.2]
1324.5 Initial Pressure Tests – Medical Gas and Vac- uum Systems. Each section of the piping in medical gas and vacuum systems shall be pressure tested. Initial pressure tests shall be conducted as follows:
(1) After blowdown of the distribution piping.
(2) After installation of station outlet/inlet rough-in assemblies.
(3) Prior to the installation of components of the distribution piping system that would be damaged by the test pressure (e.g., pressure/vacuum alarm devices, pressure/vacuum indicators, line pressure relief valves). [NFPA 99:5.1.12.2.3.1, 5.1.12.2.3.2]
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HEALTH CARE FACILITIES AND MEDICAL GAS AND MEDICAL VACUUM SYSTEMS
1324.5.1 Shutoff Valve. The source shutoff valve shall
remain closed during tests specified in Section 1324.5 through Section 1324.5.1.2. [NFPA 99:5.1.12.2.3.3]
CPC § 1324.5.8 High relevance — show source text
1324.5.8 Particulate Matter. In order to remove any traces of particulate matter deposited in the pipelines as a result of construction, a heavy, intermittent purging of the pipeline shall be done. [NFPA 99:5.1.12.4.6]
1324.5.9 Final Tie-In Test. Each joint in the final connection between the new work and the existing system shall be leak-tested with the gas of system designation at the normal operating pressure by means of a leak detectant that is safe for use with oxygen and does not contain ammonia. [NFPA 99:5.1.12.4.9.2]
1324.5.9.1 Vacuum Joints. Vacuum joints shall be tested using an ultrasonic leak detector or other means that will allow detection of leaks in an active
vacuum system. [NFPA 99:5.1.12.4.9.3] 1324.5.9.2 Pressure Gases. For pressure gases, immediately after the final brazed connection is made and leak-tested, an outlet in the new piping and an outlet in the existing piping that are immediately downstream from the point or area of intrusion shall be purged in accordance with the applicable requirements of Section 1324.5.8. [NFPA 99:5.1.12.4.9.4]
1324.5.9.3 Positive Pressure Gases. Before the new work is used for patient care, positive pressure gases shall be tested for operational pressure and gas concentration in accordance with Section 1324.5.10 and Section 1324.5.11. [NFPA 99:5.1.12.4.9.5]
1324.5.9.4 Permanent Records. Permanent
records of these tests shall be maintained in accordance with NFPA 99. [NFPA 99:5.1.12.4.9.6]
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HEALTH CARE FACILITIES AND MEDICAL GAS AND MEDICAL VACUUM SYSTEMS
1324.5.10 Operational Flow Pressure Drop Test. Operational flow pressure drop tests shall be performed at each station outlet/inlet or terminal where the user
makes connections and disconnections. [NFPA 99: 5.1.12.4.10]
1324.5.10.1 Medical-Surgical Vacuum Inlets. Medical-surgical vacuum inlets shall draw 3 SCFM (85 Nl/min) without reducing the vacuum pressure below 12 inch (305 mm) gauge HgV at any adjacent station inlet. [NFPA 99:5.1.12.4.10.4]
1324.5.10.2 Oxygen and Medical Air Outlets. Oxygen and medical air outlets serving Category 1 space shall allow a transient flow rate of 6 SCFM (170 SLPM) for 3 seconds. [NFPA 99:5.1.12.4.10.5]
1324.5.11 Medical Gas Concentration Test. After
purging each system with the gas of system designation, the following shall be performed:
(1) Each pressure gas source and outlet shall be analyzed for concentration of gas, by volume.
(2) Analysis shall be conducted with instruments designed to measure the specific gas dispensed.
CPC § 1324.5.7 High relevance — show source text
1324.5.7 System Verification. Verification tests shall be performed only after all tests required in Section
1324.3 through Section 1324.5.5.7, Installer Performed Tests, have been completed. [NFPA 99:5.1.12.4.1.1] 1324.5.7.1 Test Gas. The test gas shall be oil-free, dry nitrogen NF or the system gas where permitted.
[NFPA 5.1.12.4.1.2]
1324.5.7.2 Approved Tester. Testing shall be conducted by a party technically competent and experienced in the field of medical gas and vacuum pipeline testing and meeting the requirements of ASSE/IAPMO/ANSI 6030, except as required by Section 1324.5.7.3. [NFPA 99:5.1.12.4.1.3]
Testing shall be performed by a party other than the installing contractor. [NFPA 99:5.1.12.4.1.5]
Where systems have not been installed by inhouse personnel, testing shall be permitted by personnel of that organization who meet the requirements of Section 1324.5.7.2. [NFPA 99:5.1.12.4.1.6]
1324.5.7.3 Cryogenic Fluid Testing. Testing of the cryogenic fluid central supply system shall be conducted by a party technically competent and experienced in the field of cryogenic fluid systems and meeting the requirements of ASSE/IAPMO/ANSI 6035, in accordance with the mandatory requirements in CGA M-1. [NFPA 99:5.1.12.4.1.4]
1324.5.8 Particulate Matter. In order to remove any traces of particulate matter deposited in the pipelines as a result of construction, a heavy, intermittent purging of the pipeline shall be done. [NFPA 99:5.1.12.4.6]
1324.5.9 Final Tie-In Test. Each joint in the final connection between the new work and the existing system shall be leak-tested with the gas of system designation at the normal operating pressure by means of a leak detectant that is safe for use with oxygen and does not contain ammonia. [NFPA 99:5.1.12.4.9.2]
1324.5.9.1 Vacuum Joints. Vacuum joints shall be tested using an ultrasonic leak detector or other means that will allow detection of leaks in an active
vacuum system. [NFPA 99:5.1.12.4.9.3] 1324.5.9.2 Pressure Gases. For pressure gases, immediately after the final brazed connection is made and leak-tested, an outlet in the new piping and an outlet in the existing piping that are immediately downstream from the point or area of intrusion shall be purged in accordance with the applicable requirements of Section 1324.5.8. [NFPA 99:5.1.12.4.9.4]
1324.5.9.3 Positive Pressure Gases. Before the new work is used for patient care, positive pressure gases shall be tested for operational pressure and gas concentration in accordance with Section 1324.5.10 and Section 1324.5.11. [NFPA 99:5.1.12.4.9.5]
CPC § 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
CPC § 11.0 Medium relevance — show source text
11.0 - 1.11.11_|||X|||||||||||||||||||||| |1.13.0||||||||||||||||||||X||||| |Division II - Scope and
Administration||||||||||||||||||||||||| |101.0||||||||||X|X|X||X|X|||||||||| |102.0||||||||||X|X|X||X|X|||||||||| |103.0||||||||||X|X|X||X|X|||||||||| |104.2 Items 1 & 2||||X|X|||||||||||||||||||| |104.3.1||||||||||X|X|X||X|X|||||||||| |104.4.3.1|X|||||||||||||||||||||||| |105.0||||||||||X|X|X||X|X||||||||||This state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.0.
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CHAPTER 1
ADMINISTRATION
DIVISION I
CALIFORNIA ADMINISTRATION
1.1.0 General.
1.1.1 Title. These regulations shall be known as the Califor- nia Plumbing Code, may be cited as such and will be referred to herein as “this code.” The California Plumbing Code is Part 5 of thirteen parts of the official compilation and publi- cation of the adoption, amendment, and repeal of plumbing regulations to the California Code of Regulations, Title 24, also referred to as the California Building Standards Code. This part incorporates by adoption the 2024 Uniform Plumb- ing Code of the International Association of Plumbing and Mechanical Officials with necessary California amendments.
1.1.2 Purpose. The purpose of this code is to establish the minimum requirements to safeguard the public health, safety and general welfare through structural strength, means of egress facilities, stability, access to persons with disabilities, sanitation, adequate lighting and ventilation, and energy con- servation; safety to life and property from fire and other haz- ards attributed to the built environment; and to provide safety to fire fighters and emergency responders during emergency operations.
1.1.3 Scope. The provisions of this code shall apply to the construction, alteration, movement, enlargement, replace- ment, repair, equipment, use and occupancy, location, main- tenance, removal, and demolition of every building or structure or any appurtenances connected or attached to such buildings or structures throughout the State of California.
CPC § 4.1 Medium relevance — show source text
- 100°F
(16°C-38°C)|1 h|6 h|2 h|12 h|6 h|24 h| |40°F-60°F
(4°C-16°C)|2 h|12 h|4 h|24 h|12 h|48 h| |10°F- 40°F
(-12°C+4°C)|8 h|48 h|16 h|96 h|48 h|8 days| |*If gaps or loose fits are encountered in the system, double these cure times.|*If gaps or loose fits are encountered in the system, double these cure times.|*If gaps or loose fits are encountered in the system, double these cure times.|*If gaps or loose fits are encountered in the system, double these cure times.|*If gaps or loose fits are encountered in the system, double these cure times.|*If gaps or loose fits are encountered in the system, double these cure times.|*If gaps or loose fits are encountered in the system, double these cure times.|
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IS 33
FIGURE 1
LOCATION OF THRUST BLOCKS (STANDARD AND METRIC COMBINED) A COMPARISON OF THRUST-BLOCK AREAS (See Section 4.1)
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IS 33
FIGURE 2
THRUST BLOCK BEARING AREA (See Section 5.2.2)
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IS 33
Uniform Plumbing Code References for Ductile Iron and PVC Pressure Building Supply and Exterior Cold-Water Piping
The following sections of the 2024 Uniform Plumbing Code apply to ductile iron and PVC pressure building supply and exterior cold-water piping.
Chapter 3 General Regulations
309.0 Workmanship
312.0 Protection of Piping, Materials, and Struc tures
313.0 Hangers, Supports, and Anchors
314.0 Trenching, Excavation, and Backfill
Chapter 6 Water Supply and Distribution
604.0 Materials (water piping)
Table 604.1 Materials for Building Supply and Water Distribution Piping and Fittings
605.4 Ductile Iron Pipe and Joints
605.12 PVC Plastic Pipe and Joints
605.16.2 Plastic Pipe to Other Materials
609.0 Installation, Testing, Unions, and Location
Abbreviations
IAPMO International Association of Plumbing and Mechanical Officials
UPC Uniform Plumbing Code published by IAPMO
AWWA American Water Works Association
CSA Canadian Standards Association
Applicable Standards.
ASME B16.4 Gray Iron Threaded Fittings Classes 125 and 250
ASTM D1785 Poly (Vinyl Chloride) (PVC) Plastic Pipe, Schedules 40, 80, and 120
ASTM D2241 Poly (Vinyl Chloride) (PVC) Pressure-Rated Pipe (SDR Series)
- 100°F
CPC § 103 Medium relevance — show source text
FLOW
GPMFIXTURE UNITS Col3 FLOW
GPMFLUSH VALVE
TANKSFLUSHOMETER
VALVES1 0 — 2 1 — 3 3 — 4 4 — 5 6 — 6 7 — 7 8 — 8 10 — 9 12 — 10 13 — 11 15 — 12 16 — 13 18 — 14 20 — 15 21 — 16 23 — 17 24 — 18 26 — 19 28 — 20 30 — 21 32 — 22 34 5 23 36 6 24 39 7 25 42 8 26 44 9 27 46 10 28 49 11 29 51 12 30 54 13 31 56 14 32 58 15 33 60 16 34 63 18 35 66 20 36 69 21 37 74 23 38 78 25 39 83 26 40 86 28 41 90 30 42 95 31 FLOW
GPMFIXTURE UNITS Col3 FLOW
GPMFLUSH VALVE
TANKSFLUSHOMETER
VALVES43 99 33 44 103 35 45 107 37 46 111 39 47 115 42 48 119 44 49 123 46 50 127 48 51 130 50 52 135 52 53 141 54 54 146 57 55 151 60 56 155 63 57 160 66 58 165 69 59 170 73 60 175 76 62 185 82 64 195 88 66 205 95 68 215 102 70 225 108 72 236 116 74 245 124 76 254 132 78 264 140 80 275 148 82 284 158 84 294 168 86 305 176 88 315 186 90 325 195 92 337 205 94 348 214 96 359 223 98 370 234 100 380 245 105 406 270 110 431 295 115 455 329 120 479 365 558 2025 CALIFORNIA PLUMBING CODE
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USEFUL TABLES
AREAS AND CIRCUMFERENCES OF CIRCLES
CPC § 1323.13.3 Medium relevance — show source text
2, 1323.13.3| |1326.4 - 1326.10|1326.5 - 1326.11| |1505.6 - 1505.14|1505.5 - 1505.13| |Figure 1505.10|Figure 1505.9| |1506.6 - 1506.13|1506.5 - 1506.12| |1603.3 - 1603.4|1603.4 - 1603.5| |Table 1603.4|Table 1603.5| |1603.5 - 1603.19|1603.6 - 1603.20| |1603.20|1503.2.4| |L 402.9 - L 402.11|L 402.8 - L 402.10| |L 404.9 - L 404.12|L 404.8 - L 404.11| |L 411.5, L 411.6|L 411.2, L411.3| |L 411.7|L 411.4| |L 411.9 - L 411.12|L 411.5 - L 411.8|
xxii 2025 CALIFORNIA PLUMBING CODE
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Uniform Plumbing Code – 2024 Edition:
The Uniform Plumbing Code is the most widely adopted plumbing code in the world. The 2024 edition contains complete “turnkey” requirements for the installation and maintenance of plumbing systems, all in one easy to use book.
Uniform Plumbing Code Illustrated Training Manual:
The UPC Illustrated Training Manual is an excellent reference for anyone involved in the plumbing industry. It contains an extensive definitions section and several hundred comprehensive technical diagrams and illustrations. It serves as a textbook, and it also is useful as a valuable tool for explaining the intent and use of the Code.
Uniform Plumbing Code Study Guide:
This book is the perfect complement to the UPC Illustrated Training Manual. Alone, it constitutes a complete self-study course for learning the UPC. It has hundreds of questions, general practice exams, and plumbing math, pipe sizing exercises and fitting identification. A big help in getting you ready for a certification exam!
Guide to Important Code Questions to the Uniform Plumbing Code:
An excellent reference for learning and understanding plumbing code changes and identifies code changes between editions. It is a useful tool for preparing code change proposals.
Uniform Mechanical Code – 2024 Edition:
The Uniform Mechanical Code contains complete requirements for the installation and maintenance of heating, ventilating, cooking and refrigeration systems.
Uniform Mechanical Code Illustrated Training Manual:
Contains technical diagrams and illustrations that demonstrate the intent and use of the UMC. A great reference for everyone involved in Mechanical HVACR design and installation.
Uniform Mechanical Code Study Guide:
CPC § 102.3 Medium relevance — show source text
1
CEBC—25: California Existing Building Code
102.3, 1011.5.2, 1103.1, 1104.18, 1105.5.2
CMC—25: California Mechanical Code
201.3, 308.3, 605.1, 605.2.1.1, 605.2.1.2, 605.2.1.3, 605.2.1.4, 605.2.1.5, 605.3, 605.4, 605.4.2.3, 605.4.2.5, 605.5.2, 605.7, 606.1, 606.2, 608.1, 608.3, 608.4, 608.5, 608.8, 608.9.1, 608.10, 608.17, 610.1.1, 903.2.11.4, 904.14, 907.3.1, 909.1, 909.10.2, 909.13.1, 910.4.7, 915.6.1, 1006.2.2.3, 1011.16, 1020.6.1, 1207.4.7, 1207.6.1, 1207.6.1.2.2, 1207.11.8, 2104.2.1, 2105.3, 2301.1, 2301.6, 2309.3.1.2, 2311.3.1, 2311.4.3, 2311.8.2, 2311.8.8, 2311.8.10, 2404.9, 2404.9.2, 2504.5, 2703.2.2, 2703.10.4, 2703.14, 2803.2, 2803.3, 3001.1, 3003.1, 3004.2, 3108.12.1, 3108.12.2, 3703.5, 3804.1.1.7, 3904.1, 3905.3, Table 5003.1.1(1), 5003.8.4.2, 5003.8.5.2, 5003.8.6.2, 5004.3.1, 5303.7.6, 5303.16.9, 5305.5, 5306.2.2, 5306.2.3, 5307.4.4, 5504.2.1.3, 5504.2.2.3, 5505.4.1.1, 5701.3, 5703.6.1, 5704.2.8.9, 5705.3.7.5.1, 5706.2, 5706.4.4, 6003.1.3, 6003.2.3.2, 6004.2.2.7, 6005.3.1, 6005.3.2, 6103.2.1.7
CPC—25: California Plumbing Code
California Plumbing Code Medium relevance — show source text
2
5
10
15
20
30|184
175
215
265
312
360
461|1168
823
806
777
750
723
670|647
533
521
501
481
461
426|229
219
269
327
379
433
541|1542
1069
1049
1017
985
955
895|852
698
684
662
638
615
574|312
296
366
440
507
570
704|1971
1346
1324
1287
1251
1216
1147|1056
863
846
821
794
768
720|454
424
524
620
702
780
937|2996
1999
1971
1927
1884
1841
1759|1545
1308
1283
1243
1205
1166
1101| |50|0
2
5
10
15
20
30|176
168
204
253
299
345
442|1292
971
953
923
894
866
809|704
613
602
583
562
543
502|220
209
257
313
363
415
521|1724
1273
1252
1217
1183
1150
1086|948
811
795
765
736
708
649|295
280
347
418
481
544
674|2223
1615
1591
1551
1512
1473
1399|1189
1007
991
963
934
906
848|428
401
496
589
668
741
892|3432
2426
2396
2347
2299
2251
2159|1818
1509
1490
1455
1421
1387
1318| |100|0
2
5CPC § 101.2.2 Medium relevance — show source text
CFC—25: California Fire Code
101.2.2, 101.4.2, 301.3.1, 302.2, 307.1, 308.1, 802.2.1, 802.2.3, 803.2.3, 803.4.1.1, 803.4.1.2, 803.4.1.3, 803.4.1.4, 803.4.1.5, 803.4.1.6, Table 804.5.1.1(1), 904.1.5, 1011.6.1.1, 1303.1.2, 1305.2.8.1, 1305.2.14, 1305.2.14.1, 1401.2, 1501.1, 1501.5, 1502.1, 1502.1.1, 1502.2, 1502.3, 1504.1, 1507.1, 1507.2
CMC—25: California Mechanical Code
302.2, 702.7, 807.1, 902.1.1, 1008.1, 1305.2.7.1, 1305.2.8, 1305.2.8.1
CPC—25: California Plumbing Code
302.2, 408.1, 702.7, 1009.1, 1009.2, 1009.3, 1009.5, 1302.1.6, 1503.1
16-4 2025 CALIFORNIA EXISTING BUILDING CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
REFERENCED STANDARDS
CRC—25: California Residential Code
101.2, 101.4.1, 104.3.1, 109.3.3, 109.3.10, 302.2, 307.1, 308.1, 401.3, 402.1, 405.2.6, 502.2, 502.3, 502.4, 503.2, 503.3, 503.11, 505.2, 505.3, 507.3, 701.3, 702.4, 702.5, 706.2, 708.1, 805.2, 806.4, 809.1, 906.2, 907.1, 1011.2.1, 1103.1, 1103.2, 1103.3, 1104.1, 1201.4, 1302.1.2, 1302.1.3, 1302.1.3, 1303.1.3, 1401.2, 1402.1, 1402.2, 1402.2.1, 1402.3, 1402.4, 1402.5, 1402.6
ICC 300—2023: ICC Standard on Bleachers, Folding and Telescopic Seating and Grandstands
301.1.1, 401.1.1, 1401.1.1
ICC A117.1—2017: Accessible and Usable Buildings and Facilities
Frequently asked questions
Who must perform the tests?
Testing must be done by a party technically competent in medical gas and vacuum pipeline testing; the code prefers an independent tester meeting the competency standards referenced in § 1324.5.7.2–.3 .
What gas is used for blowdown and pressure testing?
Oil‑free, dry nitrogen NF is the test gas specified for blowdown and many verification tests (§ 1324.3) .
What test pressure do I use if my system operates at 100 psi?
Use 1.5 × 100 psi = 150 psi; because the rule is 1.5× operating pressure but not less than 150 psi, you would still test at 150 psi in this case (§ 1324.5.1.1) .
How must vacuum joints be tested?
Vacuum joints must be tested using an ultrasonic leak detector or other method capable of detecting leaks in an active vacuum system (§ 1324.5.9.1) .
Can I use a soap solution for leak detection on oxygen piping?
No — the code requires leak detectant that is safe for use with oxygen and does not contain ammonia for final tie‑in leak tests (§ 1324.5.9) .
Must final test records be kept?
Yes — permanent records of the final tie‑in tests are required to be maintained as stated in § 1324.5.9.4 .
More in California Plumbing Code
- Administration
- Definitions
- General Regulations
- Plumbing Fixtures and Fixture Fittings
- Water Heaters
- Water Supply and Distribution
- Sanitary Drainage (Drain, Waste, and Vent)
- Indirect Wastes
- Vents
- Traps and Interceptors
- Storm Drainage
- Fuel Gas Piping
- Health Care Facilities — Medical Gas and Medical Vacuum Systems
- Alternate Water Sources and Nonpotable Rainwater Catchment Systems
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Operational flow pressure-drop tests and medical gas concentration testing before service
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Alarms, pressure/vacuum indicators and emergency shutoff valve requirements
Installation, commissioning tests, alarms, labeling, installer qualifications and records
California Plumbing Code