CPC · California Plumbing Code

Central supply, source equipment and redundancy (compressors, cylinders, concentrators, cryogenic)

The CPC requires medical gas and vacuum sources to be arranged so the central system still meets peak demand with the largest single source out of service. Category 1 compressors must have at least two units and be sized accordingly; Category 2 and 3 allow specific alternate sources (e.g., concentrators, cylinder headers, cryogenic) but have defined limits and backup rules. Vacuum receivers and filters have explicit strength, drain and HEPA/duplex sizing requirements. See **§ 1310.3.1**, **§ 1312.3**, **§ 1325.3**, **§ 1326.3** for the governing language. filefilefile

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Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

The California Plumbing Code requires that central medical gas and vacuum supplies be configured so a continuous supply is maintained despite a single equipment or piping fault. Category-based provisions describe what source types are permitted and the minimum redundancy or arrangements required: Category 1 compressor systems must meet peak demand with the largest single compressor out of service and have no fewer than two compressors (see § 1310.3.1 and § 1310.3.2) . For Category 2 and Category 3 systems the code permits specific source types and allows reduced redundancy only where explicitly stated (see § 1325.3 and § 1326.3) . For medical‑surgical vacuum receivers there are explicit construction, pressure and capacity requirements (see § 1312.3) .

The single most important planning rule: design central gas and vacuum sources so the system still meets peak calculated demand when the largest single source is out of service. This is mandated for Category 1 compressors/pumps and echoed in the vacuum requirements. § 1310.3.1, § 1312.2 .

Requirements in detail

Scope and permitted source types (Category-level)

  • Category 1 (highest acuity): Central supply systems and compressor arrangements subject to Category 1 rules (see Parts II & related sections). For medical air compressors the system must be sized to serve peak demand with the largest single compressor out of service and in no case have fewer than two compressors (§ 1310.3.1) .
  • Category 2: Central supply systems must comply with the same central-supply provisions listed in § 1307.3 – § 1309.13 (the CPC references those sections), and Category 2 may allow some components to be simplex where specifically permitted; oxygen concentrator systems may be two sources with one cylinder header sized for approximately one average day’s supply (§ 1325.3, § 1325.4, § 1325.5) .
  • Category 3: The code explicitly permits a range of source types for Category 3 medical air central supply: gas cylinder or cryogenic liquid container headers, oxygen concentrator supply units, cylinder manifolds, manifolds for cryogenic liquid containers, cryogenic fluid central supply systems, medical air compressor systems, and proportioning air systems, etc. (items (1)–(7) in § 1326.3) .

Redundancy and single-fault criteria

  • Single-fault continuous supply: Components must be arranged to allow service and maintain continuous supply in the event of a single fault failure; component arrangements may vary by technology so long as the same level of redundancy and air quality is maintained (§ 1310.3.2(1)) .
  • Compressor specific: Medical air compressor systems must include automatic backflow prevention between on‑cycle and off‑cycle compressors, isolation valves to allow servicing without loss of system pressure, intake dry-type filter‑mufflers, and pressure relief valves set at 50% above line pressure (§ 1310.3.2(2)–(6)) .
  • Vacuum systems: Medical‑surgical vacuum sources shall include two or more vacuum pumps sufficient to serve peak demand with the largest single vacuum pump out of service, automatic backflow prevention, and isolation means to service pumps without loss of vacuum (§ 1312.2(1)–(3)) .

Receiver, filtration and mechanical limits

  • Vacuum receivers must be made of manufacturer‑suitable materials, comply with ASME Section VIII.1 where applicable, be capable of withstanding 60 psi gauge and 30 in. HgV, have a manual drain, and have capacity sized based on pump technology (§ 1312.3(1)–(5)) .
  • Vacuum filtration (except for liquid‑ring pumps) must be at least duplex (so one filter can be exchanged without impairing service), located on the patient side of the vacuum producer, be HEPA/0.3 µ, 99.97% efficient or better, and be sized so 100% of peak calculated demand is available while one filter is isolated (§ 1312.4(1)–(5, 3–4)) .
  • Medical air quality: Medical air must meet USP requirements and numerical contaminant limits in the code (e.g., ≤25 ppm gaseous hydrocarbons, particulate limits), and sources may be cylinders, bulk, compressors, or reconstituted blends per the medical‑air quality section (§ 1310.1) .

Isolation, valves and alarms

  • Source/source valves: Shutoff valves are required at the immediate connection of each central supply system to the distribution system (source valve) and a main line valve is required inside the building at the first inlet unless the source valve is inside the building or the system is wall‑mounted adjacent to the entry point (§ 1314.6–1314.7) .
  • Alarms and monitoring: Category 2 warning/alarm systems may be a single alarm panel but must be in an area of continuous surveillance while in operation; pressure/vacuum switches/sensors are mounted at the source with indicators to the master alarm panel (§ 1325.10) .

Decision‑relevant table (quick design rules)

Decision factor Required value / rule Code reference
Minimum compressors (Category 1) No fewer than two compressors; system sized to serve peak demand with largest single compressor out of service § 1310.3.1, § 1310.3.2(1)
Allowed Category 3 sources Cylinder headers, concentrators, cylinder manifolds, cryogenic manifolds, compressors, proportioning systems § 1326.3
Oxygen concentrator alternate source (Category 2) Permitted to be two sources, one being a cylinder header sized for one average day’s supply § 1325.5
Vacuum receiver design pressure Capable of 60 psi gauge and 30 in. HgV § 1312.3(3)
Vacuum filtration efficiency 0.3 µ and 99.97% HEPA (DOE‑STD‑3020); duplex; sized for 100% peak with one filter isolated § 1312.4(1,3,4)
Pressure relief for compressors Pressure relief valves set at 50% above line pressure § 1310.3.2(5)

Exceptions & special cases

  • Category 2 systems may be allowed simplex for some compressor/dryer/aftercooler/filter/regulator components when the code explicitly permits simplex operation; however the facility must have an emergency plan to address loss of service (§ 1325.4(1–2)) .
  • Category 3 systems are permitted to use less complex or different source assemblies (cylinder headers, oxygen concentrators, cryogenic systems, etc.) as listed in § 1326.3; but each listed source must meet the applicable NFPA 99 construction/performance requirements the CPC references (§ 1326.3) .
  • Where the CPC text defers to NFPA 99 for construction, installation or performance details (much of the central supply language does), follow NFPA 99 provisions in addition to these CPC citations — the CPC identifies permitted source types but relies on NFPA 99 for many technical details (see § 1326.3, § 1325.3) file.

If a specific construction or operational parameter is not present in the CPC snippets retrieved here (for example, detailed cryogenic piping installation standards or certain instrument calibration tolerances), the CPC delegates to NFPA 99 and related standards — consult NFPA 99 and the referenced sections for full technical requirements. The uploaded CPC excerpts do not reproduce the entire NFPA text; where the CPC points to NFPA 99 the detailed prescription must be read in that standard.

Common mistakes

  • Designing a two‑compressor system where each compressor cannot individually support peak demand (violates "largest single out of service" rule) — each remaining capacity must cover peak per § 1310.3.1 .
  • Omitting isolation valves or backflow prevention between compressors/pumps so maintenance forces a shutdown — the code requires isolation means and automatic backflow prevention (§ 1310.3.2(2–3), § 1312.2(2–3)) file.
  • Under‑sizing vacuum filtration bundles: filters must be duplex and sized for 100% of peak demand while one filter is removed (§ 1312.4(1,4)) .
  • Treating Category designations as cosmetic — Category 1, 2 and 3 carry real differences in permitted equipment and redundancy; assume Category 1 has the strictest redundancy requirements unless the code explicitly allows otherwise (§ 1325.3, § 1326.3) file.

Worked example — sizing compressors for redundancy (numbers)

Scenario: A clinic’s peak calculated medical‑air demand is 500 L/min. The clinic will be Category 1 and must meet peak with the largest single compressor out of service per § 1310.3.1 .

Design options that comply with the rule:

  • Option A — Two‑unit scheme: install two compressors each rated 500 L/min. If one fails, the remaining compressor can still supply 500 L/min (meets requirement). This satisfies the “no fewer than two compressors” rule as well (§ 1310.3.1) .
  • Option B — Three‑unit scheme: install three compressors rated 250 L/min each. If the largest single unit (250 L/min) is out, the remaining two provide 500 L/min combined and meet peak; this also satisfies the single-fault criterion because the remaining capacity equals peak demand (§ 1310.3.2(1)) .

Other mandatory details for either option: include automatic backflow prevention, manual isolation valves to service a unit without loss of system pressure, and pressure relief devices as required in § 1310.3.2 .

Related provisions

  • § 1310.3.1 — Category 1 compressor sizing and minimum number of compressors
  • § 1310.3.2 — Required components and single‑fault arrangements for air compressors
  • § 1312.2 — Medical‑surgical vacuum source redundancies (two or more pumps, isolation, anti‑backflow)
  • § 1312.3 — Vacuum receiver construction, pressure/vacuum withstand and capacity
  • § 1312.4 — Vacuum filtration requirements (duplex, HEPA, sizing)
  • § 1325.3 — Category 2 central supply systems shall comply with central supply sections (refer to Part II)
  • § 1325.4–1325.5 — Category 2 medical air compressors/simplex allowances and oxygen concentrator sourcing rules
  • § 1326.3 — Listing of permitted Category 3 medical air central supply source types (cylinders, concentrators, cryogenic, compressors, etc.)
  • § 1314.6–1314.7 — Source and main‑line shutoff valve placement and purpose

Code references

Grounded in the retrieved California Plumbing Code — click a citation to read the verbatim passage:

  • CPC § 5.1.3.6.3.9 High relevance — show source text

    (1) Components shall be arranged to allow service and a continuous supply of medical air in the event of a single fault failure.

    Component arrangement shall be permitted to vary as required by the technology(ies) employed, provided that an equal level of operating redundancy and medical air quality is maintained. [NFPA 99:5.1.3.6.3.9(A)(1), 5.1.3.6.3.9(A)(2)]

    (2) Automatic means to prevent backflow from all oncycle compressors through all off-cycle compressors.

    (3) Manual shutoff valve to isolate each compressor from the centrally piped system and from other compressors for maintenance or repair without loss of pressure in the system.

    (4) Intake filter-muffler(s) of the dry type.

    (5) Pressure relief valve(s) set at 50 percent above line

    pressure.

    (6) Piping and components between the compressor and the source shutoff valve that do not contribute to

    contaminant levels.

    (7) Except as defined in Section 1310.3.2(1) through Section 1310.3.2(6), materials and devices used between the medical air intake and the medical air source valve that are of any design or construction appropriate for the service as determined by the manufacturer. [NFPA 99:5.1.3.6.3.2 (2-7)]

    1310.4 Medical Air Receivers. Receivers for medical air shall meet the following requirements:

    (1) They shall be made of corrosion-resistant materials or otherwise be made corrosion resistant.

    (2) They shall comply with Section VIII.1, “Unfired Pressure Vessels,” of the ASME Boiler and Pressure Vessel Code.

    (3) They shall be equipped with a pressure relief valve, automatic drain, manual drain, sight glass, and pressure indi cator.

    (4) They shall be of a capacity sufficient to prevent the compressors from short-cycling. [NFPA 99:5.1.3.6.3.6]

    1310.5 Valves. A medical air receiver(s) shall be provided with proper valves to allow the flow of compressed air to enter and exit out of separate receiver ports during normal operation and allow the receiver to be bypassed during service without shutting down the supply of medical air. [NFPA 99:5.1.3.6.3.9(D)]

    1311.0 Compressor Intake.

    1311.1 Air Sources. Air sources for medical air compressors shall comply with Section 1311.2 through Section 1311.6.

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    HEALTH CARE FACILITIES AND MEDICAL GAS AND MEDICAL VACUUM SYSTEMS

    1311.2 Medical Air Compressor Source. The medical air compressors shall draw their air from a source of clean air. [NFPA 99:5.1.3.6.3.11(A)]

    If an air source equal to or better than outside air (e.g., air already filtered for use in operating room ventilating systems) is available, it shall be permitted to be used for the medical air compressors with the following provisions:

    (1) This alternate source of supply air shall be available on a continuous 24 hours-per-day, 7 day-per-week basis.

  • CPC § 1326.0 High relevance — show source text

    (1) Warning systems shall be permitted to be a single alarm panel.

    »

    Part IV – Category 3 Piped Gas and Vacuum Systems.

    1326.0 Category 3 Piped Gas and Vacuum Systems. 1326.1 General. Category 3 piped gas and vacuum systems shall be permitted when all of the following criteria are met:

    (1) Only minimal sedation, as defined in Chapter 2; or no sedation is performed. Deep sedation, moderate sedation, and general anesthesia are not performed.

    (2) The loss of the piped gas and vacuum systems is not likely to cause injury to patients, staff, or visitors, but can cause discomfort.

    (3) The facility piped gas and vacuum systems are intended for Category 3 patient care rooms as defined in Chapter 2. [NFPA 99:5.3.1.2]

    1326.2 Nature of Hazards of Gas and Vacuum Sys- tems. The requirement of Section 1307.2 shall apply to the nature of hazards of gas and vacuum systems. [NFPA 99:5.3.2]

    1326.3 Medical Air Supply Systems. Category 3 central supply systems shall be permitted to consist of the following:

    (1) Gas cylinder or cryogenic liquid container headers in accordance with NFPA 99.

    (2) Oxygen concentrator supply units in accordance with NFPA 99.

    (3) Cylinder manifolds for gas cylinders in accordance with NFPA 99.

    (4) Manifolds for cryogenic liquid containers in accordance with NFPA 99.

    (5) Cryogenic fluid central supply systems in accordance with NFPA 99.

    (6) Medical air compressor systems in accordance with NFPA 99.

    (7) Proportioning air systems in accordance with NFPA 99.

    (8) Medical-surgical vacuum systems in accordance with of NFPA 99.

    (9) Waste anesthetic gas disposal systems (WAGDs) in accordance with NFPA 99.

    (10)Instrument air compressor systems in accordance with NFPA 99. {NFPA 99:5.3.3.5} 1326.4 Medical–Surgical Vacuum Systems. Category 3 systems shall comply with Section 1307.3 through Section 1309.13 and Section 1312.0 through Section 1313.5, except as follows:

    (1) Medical–surgical vacuum systems shall be permitted to be simplex.

    (2) The facility staff shall develop an emergency plan to deal with the loss of medical–surgical vacuum.

    (3) Emergency electrical service shall conform to the requirements of Section 6.6 of NFPA 99 and NFPA 70.

    [NFPA 99:5.3.3.7]

    1326.5 Valves. Category 3 systems shall comply with Section 1314.0. [NFPA 99:5.3.4]

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    HEALTH CARE FACILITIES AND MEDICAL GAS AND MEDICAL VACUUM SYSTEMS

    (2) The alarm panel shall be located in an area of continuous surveillance while the facility is in operation.

    (3) Pressure and vacuum switches/sensors shall be mounted at the source equipment with a pressure indicator at the master alarm panel.

  • CPC § 1.686 High relevance — show source text

    (1) It shall be supplied from cylinders, bulk containers, or medical air compressor sources, or it shall be reconstituted from oxygen USP and oil-free, dry nitrogen NF.

    (2) It shall meet the requirements of medical air USP.

    (3) It shall have no detectable liquid hydrocarbons.

    (4) It shall have less than 25 ppm gaseous hydrocarbons. (5) It shall have equal to or less than 1.686 x 10 [-6] pounds per cubic yard (1 mg/m [3] ) of permanent particulates sized 1 micron or larger in the air at normal atmospheric pressure. [NFPA 99:5.1.3.6.1]

    1310.2 Uses of Medical Air. Medical air sources shall be connected to the medical air distribution system only and shall be used only for air in the application of human respiration and calibration of medical devices for respiratory application. [NFPA 99:5.1.3.6.2] 1310.3 Medical Air Compressors. Medical air compressors shall be installed in a well-lit, ventilated, and clean location and shall be accessible. The location shall be provided with drainage facilities in accordance with this code. The medical air compressor area shall be located separately from medical gas cylinder system sources, and shall be readily accessible for maintenance.

    1310.3.1 Category 1 Medical Air Compressor. Medical air compressors shall be sufficient to serve the peak calculated demand with the largest single compressor out of service. In no case shall there be fewer than two compressors. [NFPA 99:5.1.3.6.3.9(B)]

    1310.3.2 Required Components. Medical air compressor systems shall consist of the following:

    (1) Components shall be arranged to allow service and a continuous supply of medical air in the event of a single fault failure.

    Component arrangement shall be permitted to vary as required by the technology(ies) employed, provided that an equal level of operating redundancy and medical air quality is maintained. [NFPA 99:5.1.3.6.3.9(A)(1), 5.1.3.6.3.9(A)(2)]

    (2) Automatic means to prevent backflow from all oncycle compressors through all off-cycle compressors.

    (3) Manual shutoff valve to isolate each compressor from the centrally piped system and from other compressors for maintenance or repair without loss of pressure in the system.

    (4) Intake filter-muffler(s) of the dry type.

    (5) Pressure relief valve(s) set at 50 percent above line

    pressure.

    (6) Piping and components between the compressor and the source shutoff valve that do not contribute to

    contaminant levels.

    (7) Except as defined in Section 1310.3.2(1) through Section 1310.3.2(6), materials and devices used between the medical air intake and the medical air source valve that are of any design or construction appropriate for the service as determined by the manufacturer. [NFPA 99:5.1.3.6.3.2 (2-7)]

    1310.4 Medical Air Receivers. Receivers for medical air shall meet the following requirements:

    (1) They shall be made of corrosion-resistant materials or otherwise be made corrosion resistant.

    (2) They shall comply with Section VIII.1, “Unfired Pressure Vessels,” of the ASME Boiler and Pressure Vessel Code.

  • CPC § 1311.4 High relevance — show source text

    1311.4 Location . . . . . . . . . . . . . . . . . . . .281

    1311.5 Separate Compressors . . . . . . . . .281

    1311.6 Screening . . . . . . . . . . . . . . . . . . .281

    1312.0 Medical Surgical Vacuum Central Supply Systems . . . . . . . .281

    1312.1 General . . . . . . . . . . . . . . . . . . . . .281

    1312.2 Medical-Surgical Vacuum Sources . . . . . . . . . . . . . . . . . . . .281

    1312.3 Vacuum Receivers . . . . . . . . . . . .281

    1312.4 Vacuum Filtration . . . . . . . . . . . . .281

    1312.5 Piping Arrangement and Redundancies . . . . . . . . . . . . . . . .282

    1312.6 Piping Serviceability . . . . . . . . . . .282

    1312.7 Shutoff Valve . . . . . . . . . . . . . . . .282

    1313.0 Medical-Surgical Vacuum Exhaust . . . . . . . . . . . . . . . . . . . . .282

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    TABLE OF CONTENTS

    1313.1 Vacuum Source Exhausts . . . . . .282

    1313.2 Location . . . . . . . . . . . . . . . . . . . .282

    1313.3 Screening . . . . . . . . . . . . . . . . . . .282

    1313.4 Dips and Loops . . . . . . . . . . . . . .282

    1313.5 Multiple Pumps . . . . . . . . . . . . . . .282

    1314.0 Valves . . . . . . . . . . . . . . . . . . . . . .282

    1314.1 Gas and Vacuum Shutoff

    Valves . . . . . . . . . . . . . . . . . . . . . .282

    1314.2 Security . . . . . . . . . . . . . . . . . . . . .282

    1314.3 Labeled . . . . . . . . . . . . . . . . . . . . .282

    1314.4 Accessibility . . . . . . . . . . . . . . . . .282

    1314.5 Valve Types . . . . . . . . . . . . . . . . .282

    Table 1314.5(1) Positive Pressure Gases . . . . . . .283

    Table 1314.5(2) Vacuum and WAGD . . . . . . . . . . .283

    1314.6 Source Valves . . . . . . . . . . . . . . .283

    1314.7 Main Line Valve . . . . . . . . . . . . . .283

    1314.8 Riser Valves . . . . . . . . . . . . . . . . .283

    1314.9 Service Valves . . . . . . . . . . . . . . .283

  • CPC § 1319.0 High relevance — show source text

    (4) Vacuum receiver.

    (5) Piping between the vacuum pump(s), discharge(s), receiver(s), and vacuum source shutoff valve in accordance with Section 1319.0, except brass, galvanized, or black steel pipe, which is permitted to be used as recommended by the manufacturer.

    (6) Except as defined in Section 1312.2(1) through Section 1312.2(5), materials and devices used between the medical vacuum exhaust and the medical vacuum source that are permitted to be of any design or construction appropriate for the service as determined by the manufacturer.

    (7) Vacuum filtration per Section 1312.4. [NFPA 99:5.1.3.7.1.1]

    1312.3 Vacuum Receivers. Receivers for vacuum shall meet the following requirements:

    (1) They shall be made of materials deemed suitable by the manufacturer.

    (2) They shall comply with Section VIII.1, “Unfired Pressure Vessels,” of the ASME Boiler and Pressure Vessel Code.

    (3) They shall be capable of withstanding a gauge pressure of 60 psi (414 kPa) and 30 inch (762 mm) gauge HgV.

    (4) They shall be equipped with a manual drain.

    (5) They shall be of a capacity based on the technology of the pumps. [NFPA 99:5.1.3.7.3]

    1312.4 Vacuum Filtration. Central supply systems for vacuum other than liquid ring pumps shall be provided with inlet filtration with the following characteristics:

    (1) Filtration shall be at least duplex to allow one filter to be exchanged without impairing the vacuum system.

    (2) Filtration shall be located on the patient side of the vacuum producer.

    (3) Filters shall be efficient to 0.3 µ and 99.97 percent HEPA or better, per DOE-STD-3020.

    (4) Filtration shall be sized for 100 percent of the peak calculated demand while one filter or filter bundle is iso lated.

    (5) It shall be permitted to group multiple filters into bundles to achieve the required capacities.

    (6) The system shall be provided with isolation valves on the source side of each filter or filter bundle and isolation valves on the patient side of each filter or filter bundle, permitting the filters to be isolated without shutting off flow to the central supply system.

    (7) A means shall be available to allow the user to observe any accumulations of liquids.

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    (8) A vacuum relief petcock shall be provided to allow vacuum to be relieved in the filter canister during filter replacement.

    (9) Filter elements and canisters shall be permitted to be constructed of materials as deemed suitable by the manufacturer.

    (10)In normal operation, one filter or filter bundle shall be isolated from the system to be available for service should a blockage in the operating filter occur or rotation of the filters be desired after filter element exchange.

    [NFPA 99:5.1.3.7.4] 1312.5 Piping Arrangement and Redundancies. Piping arrangement shall be as follows:

    (1) Piping shall be arranged to allow service and a continuous supply of medical-surgical vacuum in the event of a single fault failure.

  • CPC § 5.1.3.6.3.11 High relevance — show source text

    (1) This alternate source of supply air shall be available on a continuous 24 hours-per-day, 7 day-per-week basis.

    (2) Ventilating systems having fans with motors or drive belts located in the airstream shall not be used as a source of medical air intake. [NFPA 99:5.1.3.6.3.11(E)]

    1311.3 Air Intakes. Compressor intake piping shall be permitted to be made of materials and use a joining technique as permitted under Section 1319.0 and Section 1320.0. [NFPA 99:5.1.3.6.3.11(F)]

    1311.4 Location. Medical air intakes shall be located as fol lows:

    (1) The medical air intake shall be located a minimum of 25 feet (7620 mm) from ventilating system exhausts, fuel storage vents, combustion vents, plumbing vents, vacuum and WAGD discharges, or areas that can collect vehicular exhausts or other noxious fumes.

    (2) The medical air intake shall be located a minimum of 20 feet (6096 mm) above ground level.

    (3) The medical air intake shall be located a minimum of 10 feet (3048 mm) from any door, window, or other opening in the building. [NFPA 99:5.1.3.6.3.11(B-D)] 1311.5 Separate Compressors. Air intakes for separate compressors shall be permitted to be joined together to one common intake where the following conditions are met:

    (1) The common intake is sized to minimize backpressure in accordance with the manufacturer’s recommendations.

    (2) Each compressor can be isolated by manual or check valve, blind flange, or tube cap to prevent open inlet piping when the compressor(s) is removed for service from the consequent backflow of room air into the other compressor(s). [NFPA 99:5.1.3.6.3.11(G)] 1311.6 Screening. The end of the intake shall be turned down and screened or otherwise be protected against the entry of vermin, debris, or precipitation by screening fabricated or composed of a noncorroding material. [NFPA 99:5.1.3.6.3.11(H)]

    1312.0 Medical Surgical Vacuum Central Supply Sys- tems.

    1312.1 General. The vacuum plant shall be installed in a well-lit, ventilated, and clean location with accessibility. The location shall be provided with drainage facilities in accordance with this code. The vacuum plant, where installed as a source, shall be located separately from other medical vacuum system sources and shall be readily accessible for maintenance. 1312.2 Medical-Surgical Vacuum Sources. Medicalsurgical vacuum central supply systems shall consist of the following:

    (1) Two or more vacuum pumps sufficient to serve the peak calculated demand with the largest single vacuum pump out of service.

    (2) Automatic means to prevent backflow from any on-cycle vacuum pumps through any off-cycle vacuum pumps.

    (3) Shutoff valve or other isolation means to isolate each vacuum pump from the centrally piped system, and other vacuum pumps for maintenance or repair without loss of vacuum in the system.

    (4) Vacuum receiver.

  • CPC § 1324.5.11. Medium relevance — show source text

    (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.

    (3) Allowable concentrations shall be as indicated in Table 1324.5.11. [NFPA 99:5.1.12.4.11]

    TABLE 1324.5.11

    GAS CONCENTRATIONS

    [NFPA 99: TABLE 5.1.12.4.11]

    MEDICAL GAS CONCENTRATION


    Oxygen USP    		 ≥99% oxygen


    Oxygen 93 USP    		 ≥90% oxygen≤96%


    Nitrous oxide USP    		 ≥99% nitrous oxide

    Nitrogen NF    		 ≤1% oxygen or≥99% nitrogen

    Medical air USP    		 19.5% - 23.5% oxygen
    Other gases Named gases by ±1%, or per specification

    Part III – Category 2 Piped Gas and Vacuum Systems.

    1325.0 Category 2 Piped Gas and Vacuum Systems.

    1325.1 General. Category 2 piped gas or piped vacuum system requirements shall be permitted when all of the following criteria are met:

    (1) Only moderate sedation (as defined in Chapter 2), minimal sedation (as defined in Chapter 2); or no sedation is performed. Deep sedation and general anesthesia shall not be permitted.

    (2) The loss of the piped gas or piped vacuum systems is likely to cause minor injury to patients, staff, or visitors.

    (3) The facility piped gas or piped vacuum systems are intended for Category 2 patient care space as defined in Chapter 2. [NFPA 99:5.2.1.2]

    TABLE 1324.5.11

    GAS CONCENTRATIONS

    [NFPA 99: TABLE 5.1.12.4.11]

    1325.2 Nature of Hazards of Gas and Vacuum Sys- tems. The requirement of Section 1307.2 shall apply to the nature of hazards of gas and vacuum systems. [NFPA 99:5.2.2]

    1325.3 Central Supply Systems. Category 2 systems shall comply with Section 1307.3 through Section 1309.13.

    [NFPA 99:5.2.3.4]

    1325.4 Category 2 Medical Air Supply Systems. Category 2 systems shall comply with Section 1310.0 through Section 1311.6, except as follows:

    (1) Medical air compressors, dryers, aftercoolers, filters, and regulators shall be permitted to be simplex.

    (2) The facility staff shall develop their emergency plan to deal with the loss of medical air. [NFPA 99:5.2.3.5]

    1325.5 Oxygen Concentrators. Oxygen supply systems using concentrators shall be permitted to consist of two sources, one of which shall be a cylinder header with sufficient cylinder connections for one average day’s supply.

    [NFPA 99:5.2.3.6]

    1325.6 Category 2 Medical-Surgical Vacuum. Category 2 systems shall comply with Section 1312.0 through Section 1313.5, except as follows:

  • CPC § 1326.9 Medium relevance — show source text

    1326.9 Distribution. Category 3 systems shall comply with Section 1318.0 through Section 1323.12. [NFPA 99:5.3.10]

    1326.10 Labeling and Identification. Category 3 systems shall comply with Section 1323.13 through Section 1323.15.

    [NFPA 99:5.3.11]

    Part V – Dental Gas and Vacuum Systems.

    1327.0 Dental Gas and Vacuum Systems. 1327.1 General. Dental gas and vacuum systems shall comply with this code and NFPA 99. 1327.2 Emergency Shutoff Valves (Oxygen and Nitrous Oxide).

    (1) All Category 2 medical gas systems shall have an emergency shutoff valve accessible from all use-point locations in an emergency.

    (2) Where a central medical gas supply system supplies two treatment facilities, each facility shall be provided with an emergency shutoff valve located in that treatment facility so as to be accessible from all use-point locations in an emergency.

    (3) Emergency shutoff valves shall be labeled to indicate the gas controlled by the shutoff valve and shall shut off only the gas to the treatment facility that they serve.

    (4) A remotely activated shutoff valve at a gas supply manifold shall not be used for emergency shutoff. For clinical purposes, such a remote valve actuator shall not fail-close in the event of loss of electric power. Where remote actuators are the type that fail-open, it shall be mandatory that cylinder shutoff valves be closed whenever the system is not in use. [NFPA 99:15.4.2.6.1 – 15.4.2.6.4.2]

    1327.3 Warning Systems (Oxygen and Nitrous Oxide). Category 2 warning systems shall comply with Section 1325.10 except as follows:

    (1) Warning systems shall be permitted to be a single alarm panel.

    »

    Part IV – Category 3 Piped Gas and Vacuum Systems.

    1326.0 Category 3 Piped Gas and Vacuum Systems. 1326.1 General. Category 3 piped gas and vacuum systems shall be permitted when all of the following criteria are met:

    (1) Only minimal sedation, as defined in Chapter 2; or no sedation is performed. Deep sedation, moderate sedation, and general anesthesia are not performed.

    (2) The loss of the piped gas and vacuum systems is not likely to cause injury to patients, staff, or visitors, but can cause discomfort.

    (3) The facility piped gas and vacuum systems are intended for Category 3 patient care rooms as defined in Chapter 2. [NFPA 99:5.3.1.2]

    1326.2 Nature of Hazards of Gas and Vacuum Sys- tems. The requirement of Section 1307.2 shall apply to the nature of hazards of gas and vacuum systems. [NFPA 99:5.3.2]

    1326.3 Medical Air Supply Systems. Category 3 central supply systems shall be permitted to consist of the following:

    (1) Gas cylinder or cryogenic liquid container headers in accordance with NFPA 99.

    (2) Oxygen concentrator supply units in accordance with NFPA 99.

    (3) Cylinder manifolds for gas cylinders in accordance with NFPA 99.

    (4) Manifolds for cryogenic liquid containers in accordance with NFPA 99.

  • CPC § 1307.0 Medium relevance — show source text

    Notes: 1 Includes pediatric nursery. 2 Includes obstetric recovery. 3 Emergency trauma rooms used for surgical procedures shall be classified as general operating rooms. 4 Vacuum inlets required are in addition to inlets used as part of a scavenging system for removal of anesthetizing gases.

    Part II – Category 1 Piped Gas and Vacuum Systems.

    1307.0 Central Supply Systems.

    1307.1 Terms. Where the terms medical gas or medical support gas occur, the provisions shall apply to all piped systems for oxygen, nitrous oxide, medical air, carbon dioxide, helium, nitrogen, instrument air, and mixtures thereof. Wherever the name of a specific gas service occurs, the provision shall apply only to that gas. [NFPA 99:5.1.1.3] 1307.2 Nature of Hazards of Gas and Vacuum Sys- tems. Potential fire and explosion hazards associated with positive pressure gas central piping systems and medical–surgical vacuum systems shall be considered in the design, installation, testing, operation, and maintenance of these systems. [NFPA 99:5.1.2]

    1307.3 Permitted Locations for Medical Gases. Central supply systems for oxygen, medical air, nitrous oxide, carbon dioxide, and all other patient medical gases shall be piped only to medical gas outlets complying with Section 1315.0, into areas where the gases will be used under the direction of licensed medical professionals for purposes congruent with the following:

    (1) Direct respiration by patients.

    (2) Clinical application of the gas to a patient, such as the use of an insufflator to inject carbon dioxide into patient body cavities during laparoscopic surgery and carbon dioxide used to purge heart-lung machine blood flow

    ways.

    (3) Medical device applications directly related to respiration.

    (4) Power for medical devices used directly on patients.

    (5) Calibration of medical devices intended for Section 1307.3(1) through Section 1307.3(4).

    (6) Simulation centers for the education, training, and assessment of health care professionals. [NFPA 99:5.1.3.5.2]

    1307.4 Materials. Materials used in central supply systems shall meet the following requirements:

    (1) In those portions of systems intended to handle oxygen at gauge pressures greater than 350 pounds-force per square inch (psi) (2413 kPa), interconnecting hose shall contain no polymeric materials.

    (2) In those portions of systems intended to handle oxygen or nitrous oxide material, construction shall be compatible with oxygen under the temperatures and pressures to which the components can be exposed in the containment and use of oxygen, nitrous oxide, mixtures of these gases, or mixtures containing more than 23.5 percent oxygen.

    (3) If potentially exposed to cryogenic temperatures, materials shall be designed for low temperature service.

    (4) If intended for outdoor installation, materials shall be installed per the manufacturer’s requirements. [NFPA 99:5.1.3.5.4]

    1308.0 Pressure-Regulating Equipment.

    1308.1 Where Required. Pressure-regulating equipment shall be installed in the supply main upstream of the final linepressure valve. Where multiple piping systems for the same gas at different operating pressures are required, separate pressure-regulating equipment, relief valves, and source shutoff valves shall be provided for each pressure.

    1308.2 Pressure Relief Valves. All pressure relief valves shall meet the following requirements:

  • CPC § 1307.0 Medium relevance — show source text

    PART II Category 1 Piped Gas and Vacuum Systems . . . . . . . . . . . .278

    1307.0 Central Supply Systems . . . . . . . .278

    1307.1 Terms . . . . . . . . . . . . . . . . . . . . . .278

    1307.2 Nature of Hazards of Gas

    and Vacuum Systems . . . . . . . . .278

    1307.3 Permitted Locations for

    Medical Gases . . . . . . . . . . . . . . .278

    1307.4 Materials . . . . . . . . . . . . . . . . . . . .278

    1308.0 Pressure-Regulating Equipment . .278

    1308.1 Where Required . . . . . . . . . . . . . .278

    1308.2 Pressure Relief Valves . . . . . . . . .278

    1308.3 Pressure-Relief Valve

    Requirements . . . . . . . . . . . . . . . .279

    1309.0 Oxygen Concentrator Supply Units . . . . . . . . . . . . . . . . .279

    1309.1 Oxygen Requirements . . . . . . . . .279

    1309.2 Particulate Size . . . . . . . . . . . . . . .279

    1309.3 Suitability . . . . . . . . . . . . . . . . . . .279

    1309.4 Compatible Materials . . . . . . . . . .279

    1309.5 Oxygen Concentrator Components . . . . . . . . . . . . . . . . .279

    1309.6 Supply Air Quality . . . . . . . . . . . . .279

    1309.7 Electrical Components . . . . . . . . .279

    1309.8 Vent Valve . . . . . . . . . . . . . . . . . .279

    1309.9 Valved Sample Port . . . . . . . . . . .279

    1309.10 Suitable Filter . . . . . . . . . . . . . . . .279

    1309.11 Check Valve . . . . . . . . . . . . . . . . .279

    1309.12 Outlet Valve . . . . . . . . . . . . . . . . .279

    1309.13 Oxygen Concentration Monitor . . .280

    1310.0 Category 1 Medical Air Central Supply Systems . . . . . . . .280

    1310.1 Quality of Medical Air . . . . . . . . . .280

    1310.2 Uses of Medical Air . . . . . . . . . . .280

    1310.3 Medical Air Compressors . . . . . . .280

    1310.4 Medical Air Receivers . . . . . . . . . .280

    1310.5 Valves . . . . . . . . . . . . . . . . . . . . . .280

    1311.0 Compressor Intake . . . . . . . . . . . .280

    1311.1 Air Sources . . . . . . . . . . . . . . . . . .280

    1311.2 Medical Air Compressor Source . . . . . . . . . . . . . . . . . . . . .281

  • CPC § 1324.5.11 Medium relevance — show source text

    TABLE 1324.5.11

    GAS CONCENTRATIONS

    [NFPA 99: TABLE 5.1.12.4.11]

    1325.2 Nature of Hazards of Gas and Vacuum Sys- tems. The requirement of Section 1307.2 shall apply to the nature of hazards of gas and vacuum systems. [NFPA 99:5.2.2]

    1325.3 Central Supply Systems. Category 2 systems shall comply with Section 1307.3 through Section 1309.13.

    [NFPA 99:5.2.3.4]

    1325.4 Category 2 Medical Air Supply Systems. Category 2 systems shall comply with Section 1310.0 through Section 1311.6, except as follows:

    (1) Medical air compressors, dryers, aftercoolers, filters, and regulators shall be permitted to be simplex.

    (2) The facility staff shall develop their emergency plan to deal with the loss of medical air. [NFPA 99:5.2.3.5]

    1325.5 Oxygen Concentrators. Oxygen supply systems using concentrators shall be permitted to consist of two sources, one of which shall be a cylinder header with sufficient cylinder connections for one average day’s supply.

    [NFPA 99:5.2.3.6]

    1325.6 Category 2 Medical-Surgical Vacuum. Category 2 systems shall comply with Section 1312.0 through Section 1313.5, except as follows:

    (1) Medical-surgical vacuum systems shall be permitted to be simplex.

    (2) The facility staff shall develop their emergency plan to deal with the loss of medical-surgical vacuum. [NFPA 99:5.2.3.7]

    1325.7 Valves. Category 2 systems shall comply with Section 1314.0 through Section 1314.12.1. [NFPA 99:5.2.4]

    1325.8 Station Outlets and Inlets. Category 2 systems shall comply with Section 1315.0. [NFPA 99:5.2.5]

    1325.9 Pressure and Vacuum Indicators. Category 2 systems shall comply with Section 1316.2. [NFPA 99:5.2.8]

    1325.10 Warning Systems. Warning systems associated with Category 2 systems shall provide the master, area, and local alarm functions of a Category 1 system as required in Section 1317.0, except as follows:

    (1) Warning systems shall be permitted to be a single alarm panel.

    (2) The alarm panel shall be located in an area of continuous surveillance while the facility is in operation.

    (3) Pressure and vacuum switches/sensors shall be mounted at the source equipment with a pressure indicator at the master alarm panel. [NFPA 99:5.2.9]

    1325.11 Category 2 Distribution. Category 2 systems shall comply with Section 1318.0 through Section 1323.12.

    [NFPA 99:5.2.10]

    1325.12 Labeling and Identification. Category 2 systems shall comply with Section 1323.13 through Section 1323.15. [NFPA 99:5.2.11]

  • CPC § 1309.6 Medium relevance — show source text

    1309.6 Supply Air Quality . . . . . . . . . . . . .279

    1309.7 Electrical Components . . . . . . . . .279

    1309.8 Vent Valve . . . . . . . . . . . . . . . . . .279

    1309.9 Valved Sample Port . . . . . . . . . . .279

    1309.10 Suitable Filter . . . . . . . . . . . . . . . .279

    1309.11 Check Valve . . . . . . . . . . . . . . . . .279

    1309.12 Outlet Valve . . . . . . . . . . . . . . . . .279

    1309.13 Oxygen Concentration Monitor . . .280

    1310.0 Category 1 Medical Air Central Supply Systems . . . . . . . .280

    1310.1 Quality of Medical Air . . . . . . . . . .280

    1310.2 Uses of Medical Air . . . . . . . . . . .280

    1310.3 Medical Air Compressors . . . . . . .280

    1310.4 Medical Air Receivers . . . . . . . . . .280

    1310.5 Valves . . . . . . . . . . . . . . . . . . . . . .280

    1311.0 Compressor Intake . . . . . . . . . . . .280

    1311.1 Air Sources . . . . . . . . . . . . . . . . . .280

    1311.2 Medical Air Compressor Source . . . . . . . . . . . . . . . . . . . . .281

    1311.3 Air Intakes . . . . . . . . . . . . . . . . . . .281

    1311.4 Location . . . . . . . . . . . . . . . . . . . .281

    1311.5 Separate Compressors . . . . . . . . .281

    1311.6 Screening . . . . . . . . . . . . . . . . . . .281

    1312.0 Medical Surgical Vacuum Central Supply Systems . . . . . . . .281

    1312.1 General . . . . . . . . . . . . . . . . . . . . .281

    1312.2 Medical-Surgical Vacuum Sources . . . . . . . . . . . . . . . . . . . .281

    1312.3 Vacuum Receivers . . . . . . . . . . . .281

    1312.4 Vacuum Filtration . . . . . . . . . . . . .281

    1312.5 Piping Arrangement and Redundancies . . . . . . . . . . . . . . . .282

    1312.6 Piping Serviceability . . . . . . . . . . .282

    1312.7 Shutoff Valve . . . . . . . . . . . . . . . .282

    1313.0 Medical-Surgical Vacuum Exhaust . . . . . . . . . . . . . . . . . . . . .282

    2025 CALIFORNIA PLUMBING CODE xli

    ), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.

    TABLE OF CONTENTS

    1313.1 Vacuum Source Exhausts . . . . . .282

Frequently asked questions

What does “largest single unit out of service” mean in practice?

It means you must design the source array so that if the single largest compressor/pump fails (or is taken offline for service), the remaining installed capacity still meets the peak calculated demand. See § 1310.3.1 and § 1312.2 file.

Can Category 2 systems use a single compressor or pump?

Some Category 2 components (compressors, dryers, filters, regulators) are permitted to be simplex per § 1325.4(1), but the facility must have an emergency plan for loss of service and other Category 2 limits apply; oxygen concentrators used in Category 2 often require two sources with a cylinder header backup (§ 1325.4–1325.5) .

Are cryogenic systems allowed for small outpatient clinics?

Yes — the code explicitly permits manifolds for cryogenic liquid containers and cryogenic fluid central supply systems as Category 3 options, but installation and performance are subject to NFPA 99 and other referenced standards per § 1326.3 .

What vacuum receiver pressure ratings must I design for?

Vacuum receivers must be capable of withstanding 60 psi gauge and 30 in. HgV, and must have a manual drain and capacity sized per pump technology (§ 1312.3) .

Is duplex vacuum filtration always required?

For central supply vacuum systems other than liquid‑ring pumps, duplex inlet filtration is required so one filter can be exchanged without impairing vacuum service; filters must meet 0.3 µ / 99.97% HEPA performance and be sized for 100% peak demand while one filter is isolated (§ 1312.4) .

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