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Earlier editions: 20222019

Chapter 14 — PROCESS PIPING

1406.3 Special Requirements for HPP Gases — 2025 California Mechanical Code

California Mechanical Code (Title 24, Part 4) · 2025 edition · updated 2026-09-25 · California

CBSC: official editions, supplements and errata

Italicized text is a California amendment to the model code, as printed in the official publication.

Cite as: 2025 California Mechanical Code (Title 24, Part 4) § 1406.3 · Effective January 1, 2026 · Official source: Building Standards Commission

In addition to other requirements of this section, HPP gases shall comply with this subsection and the fire code.

1406.3.1 Special Provisions. Where HPP supply gas is carried in pressurized piping, a fail-safe system shall shut off flow due to a rupture in the piping. Where the piping originates from outside the building, the valve shall be located outside the building as close to the bulk source as practical.

1406.3.2 Piping and Tubing Installation. Piping and tubing shall be installed in accordance with approved standards. Supply piping for hazardous production materials having a health hazard ranking of 3 or 4 shall have welded connections throughout, unless an exhausted enclosure is provided.

Exception: Material that is incompatible with ferrous piping shall be permitted to be installed in nonmetallic piping with approved connections.

1406.3.3 Gas-Detection System. Where hazardous production material gas is used or dispensed and the physiological warning properties of the gas are at a higher level than the accepted permissible exposure limit (PEL) of the gas, a continuous gas-monitoring system shall be provided to detect the presence of the short-term hazard condition. Where dispensing occurs and flammable gases or vapors are capable of being present in quantities in excess of 25 percent of the lower explosive limit (LEL), a continuous gas-monitoring system shall be connected to the emergency control station. The maximum permitted time-weighted average exposures to be utilized shall be as published in 29 CFR 1910.1000.

336 2025 CALIFORNIA MECHANICAL CODE

CALIFORNIA MECHANICAL CODE – MATRIX ADOPTION TABLE

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▸Contents — California Mechanical Code (Title 24, Part 4)
California Mechanical Code (Title 24, Part 4)

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