Piping, tubing, valves, fittings and related components used for hazardous materials shall be in accordance with the following:
- Piping, tubing, valves, fittings and related components shall be designed and fabricated from materials that are compatible with the material to be contained and shall be of adequate strength and durability to withstand the pressure, structural and seismic stress and exposure to which they are subject.
- Piping and tubing shall be identified in accordance with ASME A13.1 to indicate the material conveyed.
Readily accessible manual valves or automatic remotely activated fail-safe emergency shutoff valves shall be installed on supply piping and tubing at the following locations:
- 3.1. The point of use.
- 3.2. The tank, cylinder or bulk source.
- Manual emergency shutoff valves and controls for remotely activated emergency shutoff valves shall be identified and the location shall be clearly visible, accessible and indicated by means of a sign.
- Backflow prevention or check valves shall be provided where the backflow of hazardous materials could create a hazardous condition or cause the unauthorized discharge of hazardous materials.
Where gases or liquids having a hazard ranking of:
- Health Class 3 or 4
- Flammability Class 4
- Instability Class 3 or 4
in accordance with NFPA 704 are carried in pressurized piping above 15 pounds per square inch gauge (psig) (103 kPa), an approved means of leak detection and emergency shutoff or excess flow control shall be provided. Where the piping originates from within a hazardous material storage room or area, the excess flow control shall be located within the storage room or area. Where the piping originates from a bulk source, the excess flow control shall be located as close to the bulk source as practical.
- Gravity distribution systems are prohibited unless specifically approved by the Chief.
- When such lines lead into buildings, antisiphon valves shall be installed at the highest point in the supply line where it leaves the top of the tank. Approved substitute protection may be provided for highly volatile liquids.
- Where necessary for public safety, valves shall be provided to permit proper emergency control for piping systems at each independent element of use therein. The Chief may require piping systems to be equipped with block valves at such locations as may be deemed essential for public safety.
Exceptions:
- Piping for inlet connections designed to prevent backflow.
- Piping for pressure relief devices.
Supply piping and tubing for gases and liquids having a health-hazard ranking of 3 or 4 in accordance with NFPA 704 shall be in accordance with ASME B31.3 and the following:
- Piping and tubing utilized for the transmission of highly toxic, toxic or highly volatile corrosive liquids and gases shall have welded, threaded or flanged connections throughout except for connections located within a ventilated enclosure if the material is a gas, or an approved method of drainage or containment is provided for connections if the material is a liquid.
- Piping and tubing shall not be located within corridors, within any portion of a means of egress required to be enclosed in fire-resistance-rated construction or in concealed spaces in areas not classified as Group H occupancies.
Exception: Piping and tubing within the space defined by the walls of corridors and the floor or roof above or in concealed spaces above other occupancies where installed in accordance with Section 415.11.6.4 of the California Building Code for Group H-5 occupancies.
- A normally closed remotely activated valve.
- An automatic-closing heat-activated valve.
- An approved device on each liquid transfer connection below the liquid level that shall provide a quick cut-off of flow in the event of fire.