CMC · California Mechanical Code
What workmanship, support and restraint requirements apply to process piping?
The California Mechanical Code (CMC § 1404.1) requires that process piping be installed without strain or bending and that tanks, vessels, appliances or cabinets must not be supported by piping; equipment must have independent structural support so piping remains free of imposed loads.
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
Process piping must be installed so it is not strained or bent, and no building equipment may be supported by or transfer stress into the piping. This is the controlling rule in § 1404.1 of the California Mechanical Code (CMC). § 1404.0 is the Workmanship heading that frames this requirement.
The single most important rule: do not allow piping to carry loads or forces from supported equipment — pipe must remain a pressure/flow system, not a structural support.
Requirements in detail
Plain-English translation of the rule
- Process piping must be installed free of imposed loads that would produce strain, bending, or stress in the piping itself. Tanks, vessels, vats, appliances, or cabinets must be independently supported; they cannot be hung from or rely upon piping for support. § 1404.1 states this plainly.
Why the rule exists (short)
- Strain, bending, or load transfer can cause joint failure, leakage, deformation, or fatigue — all of which create safety and environmental hazards in process piping systems. The CMC makes the prohibition explicit to prevent those failure modes. § 1404.1 is the source statement.
Decision-relevant dimensions (quick reference table)
| Decision question | Requirement / value | Code Reference |
|---|---|---|
| Is bending or strain allowed in installed process piping? | Not allowed — piping shall not be strained or bent. | § 1404.1 |
| May equipment (tanks, vessels, vats, appliances, cabinets) be supported by piping? | No — equipment shall not be supported by or develop stress on piping. | § 1404.1 |
| Does § 1404.1 specify numeric hanger spacing, load capacities, or seismic restraints? | No — § 1404.1 contains the workmanship prohibition only; it does not give spacing/load numbers. See related support sections listed below for hanger/spacer requirements. | § 1404.1 |
| If piping must move (thermal/settlement/seismic), may supports restrain it? | Supports must avoid imposing undue strain — the CMC requirement means supports/restraints must be designed or located so piping is free to expand/shift without being bent or loaded. (Requirement expressed in § 1404.1; implementation is handled in related support sections.) | § 1404.1 |
Implementation guidance (how inspectors and installers typically apply § 1404.1)
- Provide independent structural supports for heavy equipment (slab saddles, structural steel frames, hangers from the building structure), not pipe hangers.
- Use properly sized hangers and guides that support the pipe weight only and allow axial/thermal movement where required; do not use pipe as an anchor for non-piping loads.
- Where piping enters equipment, ensure flexible connectors, expansion joints, or properly designed loops relieve stresses so the equipment support does not transmit load into the pipe body — the CMC prohibition still applies. (Root rule: § 1404.1.)
Exceptions & special cases
- There are no exceptions or alternative allowances written into § 1404.1 itself; the section is a clear prohibition. If a project requires atypical arrangements (for example, very small instrument lines attached to equipment), the Authority Having Jurisdiction (AHJ) or a registered design professional must approve alternative methods consistent with safety. The CMC text for § 1404.1 does not provide special-case numeric exceptions.
- For implementation details such as support spacing, hanger strength, or seismic anchorage, other CMC provisions or referenced standards provide requirements; these are related but separate from § 1404.1 (see Related provisions). If the code text you need is not in § 1404.1, the CMC file shows the related sections where those details live. file
Common mistakes
- Assuming small-diameter piping can safely hold equipment: even small lines can fail if loaded — § 1404.1 prohibits supporting equipment on piping.
- Mounting tanks or instruments directly on flanges, valves, or branch piping instead of on independent structural supports. That transfers weight into the piping network and violates § 1404.1.
- Installing rigid supports or anchors that prevent thermal expansion, causing bending stresses: the workmanship rule requires avoiding strain — supports must be designed to prevent imposed stress. § 1404.1 establishes the prohibition; detailed support design is handled in related support sections. file
- Overlooking hidden load paths where insulation, saddles, or bundling transfers weight to pipes. Inspectors should verify equipment supports bear the load to structure, not to piping. § 1404.1 covers the prohibition.
Worked example — concrete scenario
Scenario: A chemical process room has a 500 lb stainless steel mixing vessel that must connect to a 2-inch process suction line (welded). The contractor proposes to rest one edge of the vessel on the welded branch pipe because it is convenient.
Apply § 1404.1:
- The proposal would make the piping carry part (or all) of the vessel weight and likely bend the branch, violating the prohibition that process piping shall not be strained or bent and that tanks, vessels, vats, appliances, or cabinets shall not be supported by or develop strain or stress on the piping. § 1404.1 therefore disallows that support scheme.
- Correct solution: provide an independent structural support (e.g., support frame or floor anchor) that accepts the 500 lb load. Use flexible piping connection or properly sized stub with an expansion loop so the pipe connection is free from load transfer. Verify that piping joints and the branch are not carrying the vessel load during design review and inspection. While § 1404.1 provides the prohibition, the detailed design of supports and flexible connectors should follow the installation instructions and applicable standards referenced elsewhere in the CMC. file
Related provisions
- § 1404.1 — Workmanship (general prohibition on strain/bending and on supporting equipment).
- § 1404.0 — Workmanship (chapter heading establishing scope).
- § 1405.1 / § 1405.2 — Inspections (requires rough and final piping inspections, pressure test requirements) — relevant because compliance with § 1404.1 will be checked at inspection.
- § 1406.1 — Pipe, Tubing, and Fittings (materials must comply with ASME B31.3 and be installed per manufacturer instructions) — material and installation rules interact with workmanship requirements.
- § 1406.2 — Hazardous Process Piping (HPP) — adds identification, visibility and containment requirements where hazards exist (supports and routing are especially critical for HPP).
- Mechanical/plumbing support guidance (hangers, spacing, seismic restraint) appears elsewhere in the code and referenced chapters (e.g., hanger/support rules and tables) — these contain implementational detail that complements § 1404.1 and should be consulted for hanger spacing and seismic anchorage. (See the Mechanical/Plumbing support sections in the code files.)
Code references
Grounded in the retrieved California Mechanical Code — click a citation to read the verbatim passage:
CMC § 1401.0 High relevance — show source text
334 2025 CALIFORNIA MECHANICAL CODE
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CHAPTER 14
PROCESS PIPING
1401.0 General.
1401.1 Applicability. Except as otherwise addressed in this code, this chapter shall govern the installation of process piping in or in conjunction with a building or structure located upon the premises.
1402.0 Permit.
1402.1 General. It shall be unlawful to install, alter, or repair or cause to be installed, altered, or repaired process material piping without first obtaining a permit.
Permits for process piping shall show the total number of outlets to be provided for on each system and such other information as required by the Authority Having Jurisdiction.
Fees for process piping permits are included in Table 104.5.
1403.0 Plans Required.
1403.1 General. Plans, engineering calculations, diagrams, and other data shall be submitted in one or more sets with each application for a permit. The Authority Having Jurisdiction shall be permitted to require plans, computations, and specifications to be prepared and designed by a registered design professional.
Where plans or other data are submitted for review, a plan review fee shall be paid, as provided in Section 104.3.2.
1404.0 Workmanship.
1404.1 General. Process piping shall not be strained or bent, nor shall tanks, vessels, vats, appliances, or cabinets be supported by or develop strain or stress on the piping.
1405.0 Inspections.
1405.1 General. Upon completion of the installation, alteration, or repair of process piping, and prior to the use thereof, the Authority Having Jurisdiction shall be notified that such piping is ready for inspection.
Excavations required for the installation of underground piping shall be kept open until such time as the piping has been inspected and approved. Where such piping is covered or concealed before such approval, it shall be exposed upon the direction of the Authority Having Jurisdiction.
1405.2 Required Inspections. The Authority Having Jurisdiction shall make the following inspections and shall either approve that portion of the work as completed or shall notify the permit holder wherein the same fails to be in accordance with this code.
1405.2.1 Rough Piping Inspection. This inspection shall be made after process piping authorized by the permit has been installed and before piping has been cov
ered or concealed. This inspection shall include a determination that the piping size, material, and installation are in accordance with the requirements of this code.
1405.2.2 Final Piping Inspection. This inspection shall be made after piping authorized by the permit has been installed and after portions thereof that are to be covered or concealed are so concealed. This inspection shall include a pressure test, at which time the piping shall stand a pressure of not less than one-and-one-half times the maximum designed operating pressure where hydraulic testing is conducted or 110 percent where testing is conducted pneumatically. Test pressures shall be held for a length of time satisfactory to the Authority Having Jurisdiction, but in no case for less than 30 minutes with no perceptible drop in pressure. HPM drain, waste, and vent piping shall be tested in accordance with the plumbing code. Tests shall be made in the presence of the Authority Having Jurisdiction. Necessary apparatus for conducting tests shall be furnished by the permit holder.
CMC § 3109F.3 High relevance — show source text
_ 5. A guide or lateral restraint shall be provided just past the elbow where a pipe changes direction in order to minimize excessive axial stress (N). 6. Piping shall be routed to allow for movement due to thermal expansion and seismic displacement, without exceeding the allowable stresses in the supports, and anchor connections (see Section 3109F.3) (N/E). 7. Plastic piping shall not be used unless designated for oil service (N/E). 8. If a flanged connection exists within 20 pipe diameters from the end of any replaced section, the pipe shall be replaced up to and including the flange. 9. Pipelines shall be seamless, electric-resistance-welded or electric-fusion-welded (N). 10. Piping greater than 2 inches in diameter shall be butt-welded. Piping 2 inches and smaller shall be socket welded or threaded. 11. Pipeline connections directly over the water shall be welded (N). Flanged connections not over water shall have secondary containment (N). 12. Pipelines that do not have a valid and certified Static Liquid Pressure Test (SLPT) [9.4] shall be marked “OUT OF SERVICE.” Out- of-service piping and pipelines shall be purged, gas-freed and physically isolated from sources of oil. 13. If a pipeline is “out-of-service” for 3 or more years, it will require a valid and certified Static Liquid Pressure Test (SLPT) and API 570 inspection [9.4] prior to Division approval for re-use (E). 14. New piping and pipeline systems require a valid and certified Static Liquid Pressure Test (SLPT) [9.4] and Division approval, prior to operation.
3109F.3 Pipeline stress analysis (N/E). Pipeline stress analysis shall be performed for: 1. New piping and pipelines 2. Significant rerouting/relocation of existing piping 3. Any replacement of “not in-kind” piping 4. Any significant rearrangement or replacement of “not in-kind” anchors and/or supports 5. Significant seismic displacements calculated from the structural and/or geotechnical assessments
Pipeline stress analysis shall be performed in accordance with ASME B31.4 [9.3], considering all relevant loads and corresponding displacements determined from the structural analysis and/or geotechnical analysis described in Sections 3104F and 3106F, respec- tively. Seismic loading of above-grade pipelines may be analyzed in accordance with ASME B31.E [9.5] with seismic loads computed from Section 3104F.5.4.1.
For pipelines spanning between seismically isolated structures (Section 3104F.1.3) and/or varying geotechnical conditions, evalua- tion of the relative movement of pipelines and supports and varying seismic accelerations shall be considered, including phase differences.
Flexibility analysis for piping, considering supports, shall be performed in accordance with ASME B31.4 [9.3] by using the largest temperature differential imposed by normal operation, start-up, shutdown or abnormal conditions. Thermal loads shall be based upon maximum and minimum local temperatures; heat traced piping shall use the maximum attainable temperature of the heat tracing system.
Section 3106F.12 provides additional considerations for underwater seafloor pipelines.
31F-84 2025 CALIFORNIA BUILDING CODE
CMC § 1.11.0. High relevance — show source text
SS/CC**|1|1R|2|3|4|5|6|6|6|6|6|6|6|6|6| |Adopting Agency
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amended (amended sections
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Chapter/Section|||||||||||||||||||||||||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.
2025 CALIFORNIA MECHANICAL CODE 333
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
334 2025 CALIFORNIA MECHANICAL CODE
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
CHAPTER 14
PROCESS PIPING
1401.0 General.
1401.1 Applicability. Except as otherwise addressed in this code, this chapter shall govern the installation of process piping in or in conjunction with a building or structure located upon the premises.
1402.0 Permit.
1402.1 General. It shall be unlawful to install, alter, or repair or cause to be installed, altered, or repaired process material piping without first obtaining a permit.
Permits for process piping shall show the total number of outlets to be provided for on each system and such other information as required by the Authority Having Jurisdiction.
Fees for process piping permits are included in Table 104.5.
1403.0 Plans Required.
1403.1 General. Plans, engineering calculations, diagrams, and other data shall be submitted in one or more sets with each application for a permit. The Authority Having Jurisdiction shall be permitted to require plans, computations, and specifications to be prepared and designed by a registered design professional.
Where plans or other data are submitted for review, a plan review fee shall be paid, as provided in Section 104.3.2.
1404.0 Workmanship.
1404.1 General. Process piping shall not be strained or bent, nor shall tanks, vessels, vats, appliances, or cabinets be supported by or develop strain or stress on the piping.
CMC § 8.10.4 High relevance — show source text
[ASHRAE 15:8.10.4] 1109.6 Support. In addition to the requirements of Section 1105.2, piping and tubing shall be securely fastened to a permanent support within 6 feet (1829 mm) following the first bend in such tubing from the compressor and within 2 feet (610 mm) of each subsequent bend or angle. Piping and tubing shall be supported at points not more than 15 feet (4572 mm) apart. 1109.7 Pipe Enclosure. Refrigerant piping and tubing shall be installed so that it is not subject to damage from an external source. Soft annealed copper tubing shall not exceed 1 [3] ⁄ 8 inches (35 mm) nominal size. Mechanical joints, other than approved press-connect joints, shall not be made on tubing exceeding [3] ⁄ 4 of an inch (20 mm) nominal size. Soft annealed copper tubing conveying refrigerant shall be enclosed in iron or steel piping and fittings, or in conduit, molding, or raceway that will protect the tubing against mechanical injury from an exterior source.
2025 CALIFORNIA MECHANICAL CODE 239
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REFRIGERATION
Exceptions: (1) Tubing entirely within or tubing within 5 feet (1524 mm) of a refrigerant compressor where so located that it is not subject to external injury. (2) Copper tubing serving a dwelling unit, where such tubing contains Group A1 refrigerant and is placed in locations not subject to damage from an external source. 1109.8 Visual Inspection. Refrigerant piping and joints erected on the premises shall be exposed to view for visual inspection prior to being covered or enclosed. Exception: Copper tubing enclosed in iron or steel piping conduit, molding, or raceway, provided there are no fittings or joints concealed therein. 1109.9 Condensation. Piping and fittings that convey brine, refrigerant, or coolants that during normal operation are capable of reaching a surface temperature below the dew point of the surrounding air and that are located in spaces or areas where condensation will cause a hazard to the building occupants or damage to the structure, electrical or other equipment shall be protected to prevent such damage. 1109.10 Identification. Piping shall be in accordance with the reference standard for identification. The type of refrigerant, function and pressure shall be indicated.
1110.0 Valves.
1110.1 More than 6.6 Pounds of Refrigerant. Systems containing more than 6.6 pounds (2.99 kg) of refrigerant shall have stop valves installed at the following locations: (1) The suction inlet of each compressor, compressor unit, or condensing unit. (2) The discharge of each compressor, compressor unit, or condensing unit. (3) The outlet of each liquid receiver. Exceptions: (1) Systems that have a refrigerant pumpout function capable of storing the entire refrigerant charge. (2) Systems that are equipped with the provisions for pumpout of the refrigerant. (3) Self-contained systems. [ASHRAE 15:9.12.4] **1110.2 More than 110 Pounds of Refrigerant.
CMC § 1315.2 High relevance — show source text
Table 1315.2(27) Schedule 40 Metallic Pipe . . . . . . 322
Table 1315.2(28) Semi-Rigid Copper Tubing . . . . . . 323
Table 1315.2(29) Semi-Rigid Copper Tubing . . . . . . 324
Table 1315.2(30) Semi-Rigid Copper Tubing . . . . . . 330
Table 1315.2(31) Corrugated Stainless Steel Tubing (CSST) . . . . . . . . . . . . . . . 326
Table 1315.2(32) Corrugated Stainless Steel Tubing (CSST) . . . . . . . . . . . . . . . 327
Table 1315.2(33) Corrugated Stainless Steel Tubing (CSST) . . . . . . . . . . . . . . . 328
Table 1315.2(34) Polyethylene Plastic Pipe . . . . . . . 329
Table 1315.2(35) Polyethylene Plastic Pipe . . . . . . . 330
Table 1315.2(36) Polyethylene Plastic Tubing . . . . . 331
CHAPTER 14 PROCESS PIPING. . . . . . . . . . . . 333
1401.0 General. . . . . . . . . . . . . . . . . . . . . 335
1401.1 Applicability. . . . . . . . . . . . . . . . . . 335
1402.0 Permit . . . . . . . . . . . . . . . . . . . . . . 335
1402.1 General. . . . . . . . . . . . . . . . . . . . . 335
1403.0 Plans Required . . . . . . . . . . . . . . . 335
1403.1 General. . . . . . . . . . . . . . . . . . . . . 335
1404.0 Workmanship . . . . . . . . . . . . . . . . 335
1404.1 General. . . . . . . . . . . . . . . . . . . . . 335
1405.0 Inspections . . . . . . . . . . . . . . . . . . 335
1405.1 General. . . . . . . . . . . . . . . . . . . . . 335
1405.2 Required Inspections . . . . . . . . . . 335
1405.3 Other Inspections . . . . . . . . . . . . . 335
1406.0 Pipe, Tubing, and Fittings. . . . . . . 335
1406.1 General. . . . . . . . . . . . . . . . . . . . . 335
1406.2 Hazardous Process
Piping (HPP). . . . . . . . . . . . . . . . . 335
1406.3 Special Requirements for HPP Gases . . . . . . . . . . . . . . . . . . . . . . 336
CHAPTER 15 SOLAR ENERGY SYSTEMS. . . . 337
CMC § 5505.1.2 High relevance — show source text
5505.1.2 Piping systems. Piping, tubing, valves and joints and fittings conveying cryogenic fluids shall be installed in accordance with the material-specific provisions of Section 5501.1 and Sections 5505.1.2.1 through 5505.1.2.6.
5505.1.2.1 Design and construction. Piping systems shall be suitable for the use intended through the full range of pressure and temperature to which they will be subjected. Piping systems shall be designed and constructed to provide adequate allowance for expansion, contraction, vibration, settlement and fire exposure.
5505.1.2.2 Joints. Joints on container piping and tubing shall be threaded, welded, silver brazed or flanged.
5505.1.2.3 Valves and accessory equipment. Valves and accessory equipment shall be suitable for the intended use at the temperatures of the application and shall be designed and constructed to withstand the maximum pressure at the minimum temperature to which they will be subjected.
5505.1.2.3.1 Shutoff valves on containers. Shutoff valves shall be provided on all container connections except for pressure relief devices. Shutoff valves shall be provided with access thereto and located as close as practical to the container.
5505.1.2.3.2 Shutoff valves on piping. Shutoff valves shall be installed in piping containing cryogenic fluids where needed to limit the volume of liquid discharged in the event of piping or equipment failure. Pressure relief valves shall be installed where liquid is capable of being trapped between shutoff valves in the piping system (see Section 5503.2).
5505.1.2.4 Physical protection and support. Piping systems shall be supported and protected from physical damage. Piping passing through walls shall be protected from mechanical damage.
5505.1.2.5 Corrosion protection. Above-ground piping that is subject to corrosion because of exposure to corrosive atmospheres, shall be constructed of materials to resist the corrosive environment or otherwise protected against corrosion. Belowground piping shall be protected against corrosion.
5505.1.2.6 Testing. Piping systems shall be tested and proven free of leaks after installation as required by the standards to which they were designed and constructed. Test pressures shall be not less than 150 percent of the maximum allowable working pressure where hydraulic testing is conducted or 110 percent where testing is conducted pneumatically.
5505.2 Indoor use. Indoor use of cryogenic fluids shall comply with the material-specific provisions of Section 5501.1.
5505.3 Outdoor use. Outdoor use of cryogenic fluids shall comply with the material specific provisions of Sections 5501.1, 5505.3.1 and 5505.3.2.
5505.3.1 Separation. Distances from lot lines, buildings and exposure hazards shall comply with Section 5504.3 and the materialspecific provisions of Section 5501.1.
5505.3.2 Emergency shutoff valves. Manual or automatic emergency shutoff valves shall be provided to shut off the cryogenic fluid supply in case of emergency. An emergency shutoff valve shall be located at the source of supply and at the point where the system enters the building.
5505.4 Filling and dispensing. Filling and dispensing of cryogenic fluids shall comply with Sections 5505.4.1 through 5505.4.3.
CMC § 312.0 High relevance — show source text
312.0 Plumbing Connections. 312.1 General. Water supply, sanitary drainage, and backflow protection shall be in accordance with the California Plumbing Code .
313.0 Hangers, Supports, and Anchors. 313.1 General. Piping, tubing, appliances, and appurtenances shall be supported in accordance with this code, the manufacturer’s installation instructions, and in accordance with the Authority Having Jurisdiction. Seismic restraints shall be in accordance with the building code. 313.2 Material. Hangers, supports, and anchors shall be of sufficient strength to support the weight of the pipe or tubing and its contents. Piping or tubing shall be isolated from incompatible materials.
313.3 Suspended Piping. Suspended piping or tubing shall be supported at intervals not to exceed those shown in Table 313.3.
313.4 Alignment. Piping or tubing shall be supported in such a manner as to maintain its alignment and prevent sagging.
313.5 Underground Installation. Piping or tubing in the ground shall be laid on a firm bed for its entire length; where other support is otherwise provided, it shall be approved in accordance with Section 302.0.
313.6 Hanger Rod Sizes. Hanger rod sizes shall be not smaller than those shown in Table 313.6.
TABLE 313.6
HANGER ROD SIZES
PIPE AND TUBE SIZE
(inches)ROD SIZES
(inches)
1⁄2 - 43⁄8
5 - 81⁄2
10 - 125⁄8 For SI units: 1 inch = 25.4 mm
313.7 Gas Piping. Gas piping shall be supported by metal straps or hooks at intervals not to exceed those shown in Table 1310.3.5.1.
314.0 Balancing.
314.1 General. Heating, ventilating, and air-conditioning systems (including hydronic systems) shall be balanced in accordance with one of the following methods:
TABLE 313.6
HANGER ROD SIZES
(1) AABC National Standards for Total System Balance
(2) ACCA Manual B
(3) ASHRAE 111
(4) NEBB Procedural Standards for Testing Adjusting Balancing of Environmental Systems
(5) SMACNA HVAC Systems Testing, Adjusting, and Balancing
315.0 Louvers in Hurricane Prone Regions.
315.1 General. Louvers located in areas within hurricane prone regions that are within 1 mile (2 km) of the coastal mean high water line where the basic wind speed is 110 miles per hour (mi/h) (49.2 m/s) or more; or portions of hurricane-prone regions where the basic wind speed is 120 mi/h (53.6 m/s) or more; or Hawaii, shall be tested in accordance with Section 315.1.1 and Section 315.1.2.
315.1.1 Testing. Louvers that protect air intake or exhaust openings shall be tested in accordance with AMCA 550 for resistance to wind-driven rain.
315.1.2 Impact Resistance Test. Upon request by the Authority Having Jurisdiction, louvers protecting intake and exhaust ventilation ducts that are not fixed in the
CMC § 20.1. High relevance — show source text
(2) Solvent cement joints for PVC pipe and fittings shall be clean from dirt and moisture. Pipe shall be cut square and pipe shall be deburred. Where surfaces to be joined are cleaned and free of dirt, moisture, oil, and other foreign material, apply primer purple in color in accordance with ASTM F656. Primer shall be applied until the surface of the pipe and fitting is softened. Solvent cements in accordance with ASTM D2564 shall be applied to all joint surfaces. Joints shall be made while both the inside socket surface and outside surface of pipe are wet with solvent cement. Hold joint in place and undisturbed for 1 minute after assembly.
(3) Threads shall comply with ASME B1.20.1. A minimum of Schedule 80 shall be permitted to be threaded; however, the pressure rating shall be reduced by 50 percent. The use of molded fittings shall not result in a 50 per
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(1) Butt-fusion joints shall be installed in accordance with ASTM F2620 and shall be made by heating the squared ends of two pipes, pipe and fitting, or two fittings by holding ends against a heated element. The heated element shall be removed where the proper melt is obtained, and joined ends shall be placed together with applied force. (2) Electro-fusion joints shall be heated internally by a conductor at the interface of the joint. Align and restrain fitting to pipe to prevent movement and apply electric current to the fitting. Turn off the current when the proper time has elapse to heat the joint. The joint shall fuse together and remain undisturbed until cool. (3) Socket-fusion joints shall be installed in accordance ASTM F2620 and shall be made by simultaneously heating the outside surface of a pipe end and the inside of a fitting socket. Where the proper melt is obtained, the pipe and fitting shall be joined by inserting one into the other with applied force. The joint shall fuse together and remain undisturbed until cool.
(4) Mechanical joints between PE pipe or tubing and fittings shall include insert and mechanical compression fittings that provide a pressure seal resistance to pullout. Joints for insert fittings shall be made by cutting the pipe square, using a cutter designed for plastic piping, and removal of sharp edges. Two stainless steel clamps shall be placed over the end of the pipe. Fittings shall be checked for proper size based on the diameter of the pipe. The end of pipe shall be placed over the barbed insert fitting, making contact with the fitting shoulder. Clamps shall be positioned equal to 180 degrees (3.14 rad) apart and shall be tightened to provide a leak tight joint. Compression type couplings and fittings shall be permitted for use in joining PE piping and tubing. Stiffeners that extend beyond the clamp or nut shall be prohibited. Bends shall be not less than 30 pipe diameters, or the coil radius where bending with the coil. Bends shall not be permitted closer than 10 pipe diameters of a fitting or valve. Mechanical joints shall be designed for their intended use. 1211.10 Polyethylene/Aluminum/Polyethylene (PE- AL-PE). Joints between polyethylene/aluminum/polyethylene (PE-AL-PE) pipe and fittings shall be installed in accordance with one of the following methods: (1) Mechanical joints for PE-AL-PE pipe or tubing and fittings shall be either of the metal insert fittings with a split ring and compression nut or metal insert fittings with copper crimp rings.
CMC § 7.3.4 Medium relevance — show source text
the tubing and the finished wall and extends at least 4 inches (102 mm) beyond concealed penetrations of plates, firestops, wall studs, and so on.
(2) The tubing is installed in single runs and is not rigidly secured. [NFPA 54:7.3.4]
1310.4.4 Industrial Occupancies. In industrial occupancies, gas piping in solid floors such as concrete shall be laid in channels in the floor and covered to permit access to the piping with a minimum of damage to the building. Where piping in floor channels could be exposed to excessive moisture or corrosive substances, the piping shall be protected in an approved manner.
[NFPA 54:7.3.5.1]
1310.4.5 Other Occupancies. In other than industrial occupancies and where approved by the Authority Having Jurisdiction, gas piping embedded in concrete floor slabs constructed with Portland cement shall be surrounded with a minimum of 1 [1] ⁄ 2 inches (38 mm) of concrete and shall not be in physical contact with other metallic structures such as reinforcing rods or electrically neutral conductors. All piping, fittings, and risers shall be protected against corrosion in accordance with Section 1310.3.1. Piping shall not be embedded in concrete slabs containing quickset additives or cinder aggregate. [NFPA 54:7.3.5.2]
1310.5 Piping in Vertical Chases. Where gas piping exceeding 5 psi (34 kPa) is located within vertical chases in accordance with Section 1310.6, the requirements of Section 1310.5.1 through Section 1310.5.3 shall apply. [NFPA 54:7.4]
1310.5.1 Pressure Reduction. Where pressure reduction is required in branch connections for compliance with Section 1310.6, such reduction shall take place either inside the chase or immediately adjacent to the outside wall of the chase. Regulator venting and downstream overpressure protection shall comply with Section 1308.6.4 and Section 1308.7. The regulator shall be accessible for service and repair, and vented in accordance with one of the following:
(1) Where the fuel gas is lighter than air, regulators equipped with a vent limiting means shall be permitted to be vented into the chase. Regulators not equipped with a vent limiting means shall be permitted to be vented either directly to the outdoors or to a point within the top 1 foot (305 mm) of the chase.
(2) Where the fuel gas is heavier than air, the regulator vent shall be vented only directly to the outdoors.
[NFPA 54:7.4.1]
1310.5.2 Chase Construction. Chase construction
shall comply with local building codes with respect to fire resistance and protection of horizontal and vertical openings. [NFPA 54:7.4.2]
1310.5.3 Ventilation. A chase shall be ventilated to the
outdoors and only at the top. The opening(s) shall have a minimum free area [in square inches (square meters)] equal to the product of one-half of the maximum pressure in the piping [in pounds per square inch (kilopas
cals)] times the largest nominal diameter of that piping
CMC § 312.0 Medium relevance — show source text
Note: Accessory dwelling units are not required to have inde- pendent service utility (drainage) connections provided they meet the specific requirements in Government Code Section 65852.2.
312.0 Protection of Piping, Tubing, Materials, and Structures.
312.1 General. Piping passing under or through walls shall be protected from breakage. Piping passing through or under cinders or other corrosive materials shall be protected from external corrosion in an approved manner. Approved provisions shall be made for expansion of hot water piping. Voids around piping passing through concrete floors on the ground shall be sealed.
312.2 Installation. Piping in connection with a plumbing system shall be so installed that piping or connections will not be subject to undue strains or stresses, and provisions shall be made for expansion, contraction, and structural settlement. No plumbing piping shall be directly embedded in concrete or masonry. No structural member shall be seriously weakened or impaired by cutting, notching, or otherwise, as defined in the California Building Code or California Residential Code . 312.3 Building Sewer and Drainage Piping. No building sewer or other drainage piping or part thereof, constructed of materials other than those approved for use under or within a building, shall be installed under or within 2 feet (610 mm) of a building or structure, or less than 1 foot (305 mm) below the surface of the ground. 312.4 Corrosion, Erosion, and Mechanical Damage. Piping subject to corrosion, erosion, or mechanical damage shall be protected in an approved manner. 312.5 Protectively Coated Pipe. Protectively coated pipe or tubing shall be inspected and tested, and a visible void, damage, or imperfection to the pipe coating shall be repaired in an approved manner. 312.6 Freezing Protection. No water, soil, or waste pipe shall be installed or permitted outside of a building, in attics or crawl spaces, or in an exterior wall unless, where necessary, adequate provision is made to protect such pipe from freezing. 312.7 Fire-Resistant Construction. Piping penetrations of fire-resistance-rated walls, partitions, floors, floor/ceiling assemblies, roof/ceiling assemblies, or shaft enclosures shall be protected in accordance with the requirements of the Cal- ifornia Building Code or California Residential Code . 312.8 Waterproofing of Openings. Joints at the roof around pipes, ducts, or other appurtenances shall be made watertight by the use of lead, copper, galvanized iron, or other approved flashings or flashing material. Exterior wall openings shall be made watertight. Counterflashing shall not restrict the required internal cross-sectional area of the vent. 312.9 Steel Nail Plates. Plastic piping or tubing, and copper or copper alloy piping or tubing penetrating framing members to within 1 inch (25.4 mm) of the exposed framing shall be protected by steel nail plates not less than No. 18 gauge (0.0478 inches) (1.2 mm) in thickness. The steel nail plate shall extend along the framing member not less than 1 [1] ⁄ 2 inches (38 mm) beyond the outside diameter of the pipe or tubing. Fuel gas piping shall be protected in accordance with Section 1210.4.3.
CMC § 1402.1 Medium relevance — show source text
1402.1 General. . . . . . . . . . . . . . . . . . . . . 335
1403.0 Plans Required . . . . . . . . . . . . . . . 335
1403.1 General. . . . . . . . . . . . . . . . . . . . . 335
1404.0 Workmanship . . . . . . . . . . . . . . . . 335
1404.1 General. . . . . . . . . . . . . . . . . . . . . 335
1405.0 Inspections . . . . . . . . . . . . . . . . . . 335
1405.1 General. . . . . . . . . . . . . . . . . . . . . 335
1405.2 Required Inspections . . . . . . . . . . 335
1405.3 Other Inspections . . . . . . . . . . . . . 335
1406.0 Pipe, Tubing, and Fittings. . . . . . . 335
1406.1 General. . . . . . . . . . . . . . . . . . . . . 335
1406.2 Hazardous Process
Piping (HPP). . . . . . . . . . . . . . . . . 335
1406.3 Special Requirements for HPP Gases . . . . . . . . . . . . . . . . . . . . . . 336
CHAPTER 15 SOLAR ENERGY SYSTEMS. . . . 337
1501.0 General. . . . . . . . . . . . . . . . . . . . . 339
1501.1 Applicability. . . . . . . . . . . . . . . . . . 339
1502.0 General. . . . . . . . . . . . . . . . . . . . . 339
CHAPTER 16 STATIONARY POWER
PLANTS . . . . . . . . . . . . . . . . . . . . 341
1601.0 Stationary Fuel Cell Power Plants . . . . . . . . . . . . . . . . . . . . . . 343
1601.1 General. . . . . . . . . . . . . . . . . . . . . 343
1602.0 Stationary Gas Engines and Generators and Gas Turbines . . . 343
1602.1 Gas Engines . . . . . . . . . . . . . . . . . 343
1602.2 Liquid-Fueled Engines and Gas Turbines . . . . . . . . . . . . . . . . 343
1602.3 Stationary Engine Generators . . . 343
CHAPTER 17 GEOTHERMAL ENERGY
SYSTEMS AND AMBIENT
TEMPERATURE LOOPS. . . . . . . 345
Part I General . . . . . . . . . . . . . . . . . . . . 347
1701.0 General. . . . . . . . . . . . . . . . . . . . . 347
CMC § 313.0 Medium relevance — show source text
313.0 Hangers, Supports, and Anchors. 313.1 General. Piping, tubing, fixtures, appliances, and appurtenances shall be supported in accordance with this code, the manufacturer’s installation instructions, and in accordance with the Authority Having Jurisdiction. Seismic restraints shall be in accordance with the building code. 313.2 Material. Hangers, supports, and anchors shall be of sufficient strength to support the weight of the pipe or tubing and its contents. Piping or tubing shall be isolated from incompatible materials. 313.3 Suspended Piping. Suspended piping shall be supported at intervals not to exceed those shown in Table 313.3. 313.4 Alignment. Piping shall be supported in such a manner as to maintain its alignment and prevent sagging. 313.5 Underground Installation. Piping in the ground shall be laid on a firm bed for its entire length; where other support is otherwise provided, it shall be approved in accordance with Section 301.2.
313.6 Hanger Rod Sizes. Hanger rod sizes shall be not smaller than those shown in Table 313.6.
TABLE 313.6
HANGER ROD SIZES
PIPE AND TUBE SIZE
(inches)ROD SIZE
(inches)
1⁄2 – 43⁄8
5 – 81⁄2
10 – 125⁄8 For SI units: 1 inch = 25.4 mm
313.7 Gas Piping. Gas piping shall be supported by metal straps or hooks at intervals not to exceed those shown in Table 1210.3.5.1.
313.8 [OSHPD 1, 2, 3, 4 & 5] Refer to Title 24, Part 2 of the California Building Code for seismic anchorage and bracing requirements and accommodations for building displace-
ments.
314.0 Trenching, Excavation, and Backfill.
314.1 Trenches. Trenches deeper than the footing of a building or structure, and paralleling the same, shall be located not less than 45 degrees (0.79 rad) from the bottom exterior edge of the footing, or as approved in accordance with Section 301.0.
314.2 Tunneling and Driving. Tunneling and driving shall be permitted to be done in yards, courts, or driveways of a building site. Where sufficient depth is available to permit, tunnels shall be permitted to be used between open-cut trenches.
Tunnels shall have a clear height of 2 feet (610 mm) above the pipe and shall be limited in length to one-half the depth of the trench, with a maximum length of 8 feet (2438 mm). Where pipes are driven, the drive pipe shall be not less than one size larger than the pipe to be laid.
314.3 Open Trenches. Excavations required to be made for the installation of a building drainage system or part thereof, within the walls of a building, shall be open trench work and shall be kept open until the piping has been inspected, tested, and accepted.
Frequently asked questions
Who enforces the prohibition against supporting equipment on piping?
The Authority Having Jurisdiction (AHJ) enforces the CMC; inspectors will check during rough and final piping inspections that piping is free from strain and not used as equipment support, per § 1404.1.
If a small instrument manifold touches a piece of equipment, is that a violation?
If the instrument piping or manifold carries load or is strained as a result, it violates § 1404.1. Minor incidental contact that does not transfer load is acceptable, but the installer should ensure the pipe is not bearing weight or stressed.
Does § 1404.1 give hanger spacing, rod sizes, or seismic bracing details?
No. § 1404.1 states the workmanship rule only. Spacing, hanger rod sizes, and seismic anchorage are found in other code sections and tables that govern supports; consult those related sections and tables for numeric requirements. file
What is the best way to show compliance on plans?
Show dedicated structural supports for equipment (details and load calculations), label piping supports as pipe-only, and include notes that piping will have flexible/connective details to avoid load transfer; inspectors will verify per § 1404.1 during review and inspection.
If a support inadvertently contacts a pipe, what should be done?
Modify the support so it carries the load independently (shim, isolate, or relocate), or provide a mechanical isolation/flexible connector that ensures the piping carries no load. The controlling requirement is in § 1404.1.
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