Storage, use and handling of compressed gases in compressed gas containers, cylinders, tanks and systems shall comply with this chapter and NFPA 55, including those gases regulated elsewhere in this code. Partially full compressed gas containers, cylinders or tanks containing residual gases shall be considered as full for the purposes of the controls required.
Liquefied natural gas for use as a vehicular fuel shall also comply with NFPA 52 and NFPA 59A.
Compressed gases classified as hazardous materials shall also comply with Chapter 50 for general requirements and chapters addressing specific hazards, including Chapters 58 (Flammable Gases), 60 (Highly Toxic and Toxic Materials), 63 (Oxidizers, Oxidizing Gases and Oxidizing Cryogenic Fluids) and 64 (Pyrophoric Materials).
Compressed hydrogen (CH2) for use as a vehicular fuel shall also comply with Chapters 23 and 58 of this code, the California Mechanical Code and NFPA 2.
Cutting and welding gases shall also comply with Chapter 35.
- Gases used as refrigerants in refrigeration systems (see Section 606).
- Compressed natural gas (CNG) for use as a vehicular fuel shall comply with Chapter 23, NFPA 52 and the California Mechanical Code.
- Cryogenic fluids shall comply with Chapter 55.
[California Code of Regulations, Title 19, Division 1, §3.18(a) and (b)] Hazardous Areas.
- General. Occupancies or portions thereof used or intended to be used as operating rooms, surgeries, delivery rooms, storage rooms and similar hazardous locations in which flammable or nonflammable mixtures of gases are used or stored shall be maintained in accordance with the provisions of NFPA 99-2005 Inhalation Anesthetics, NFPA 99-2005 Laboratories, NFPA 99-2005 Hyperbaric Facilities, NFPA 55-2010 Bulk Oxygen Systems at Consumer Sites, and this section.
Gas Color (1) Oxygen Green (2) Carbon Dioxide Gray (3) Nitrous Oxide Light Blue (4) Cyclopropan Orange (5) Helium Brown (6) Ethlene Red (7) Carbon Dioxide and Oxygen Gray and Green (8) Helium and Oxygen Brown and Green
The following terms are defined in Chapter 2:
COMPRESSED GAS CONTAINER.
COMPRESSED GAS SYSTEM.
Pressure relief devices shall be provided to protect containers, cylinders and tanks containing compressed gases from rupture in the event of overpressure.
Exception: Cylinders, containers and tanks where exempt from the requirements for pressure relief devices specified by the standards of design listed in Section 5303.3.2.
Pressure relief devices shall be arranged to discharge upward and unobstructed to the open air in such a manner as to prevent any impingement of escaping gas upon the container, adjacent structures or personnel.
Exception: DOTn specification containers having an internal volume of 30 cubic feet (0.855 m3) or less.
Piping systems shall be marked in accordance with ASME A13.1. Markings used for piping systems shall consist of the content’s name and include a direction-of-flow arrow. Markings shall be provided at each valve; at wall, floor or ceiling penetrations; at each change of direction; and at not less than every 20 feet (6096 mm) or fraction thereof throughout the piping run.
- Piping that is designed or intended to carry more than one gas at various times shall have appropriate signs or markings posted at the manifold, along the piping and at each point of use to provide clear identification and warning.
- Piping within gas manufacturing plants, gas processing plants, refineries and similar occupancies shall be marked in an approved manner.
Compressed gas containers, cylinders and tanks shall be secured to prevent falling caused by contact, vibration or seismic activity. Securing of compressed gas containers, cylinders and tanks shall be by one of the following methods:
- Securing containers, cylinders and tanks to a fixed object with one or more restraints.
- Securing containers, cylinders and tanks on a cart or other mobile device designed for the movement of compressed gas containers, cylinders or tanks.
- Nesting of compressed gas containers, cylinders and tanks at container filling or servicing facilities or in sellers’ warehouses not accessible to the public. Nesting shall be allowed provided the nested containers, cylinders or tanks, if dislodged, do not obstruct the required means of egress.
- Securing of compressed gas containers, cylinders and tanks to or within a rack, framework, cabinet or similar assembly designed for such use.
Exception: Compressed gas containers, cylinders and tanks in the process of examination, filling, transport or servicing.
Compressed gas containers, cylinders and tanks designed for valve protection caps or other protective devices shall have the caps or devices in place. When outlet caps or plugs are installed, they shall be in place.
Exception: Compressed gas containers, cylinders or tanks in use, being serviced or being filled.
Leaking, damaged or corroded compressed gas containers, cylinders and tanks shall be removed from service. Leaking, damaged or corroded compressed gas systems shall be replaced or repaired in accordance with the following:
- Compressed gas containers, cylinders and tanks that have been removed from service shall be handled in an approved manner.
- Compressed gas systems that are determined to be leaking, damaged or corroded shall be repaired to a serviceable condition or removed from service.
Vaults shall be listed by a nationally recognized testing laboratory.
Exception: Where approved by the fire code official, below-grade vaults are allowed to be constructed on site, provided that the design is in accordance with the California Building Code and that special inspections are conducted to verify structural strength and compliance of the installation with the approved design in accordance with Section 1707 of the California Building Code. Installation plans for below-grade vaults that are constructed on site shall be prepared by, and the design shall bear the stamp of, a professional engineer. Consideration shall be given to soil and hydrostatic loading on the floors, walls and lid; anticipated seismic forces; uplifting by ground water or flooding; and to loads imposed from above, such as traffic and equipment loading on the vault lid.
The vault shall completely enclose generation, compression, storage or dispensing equipment located in the vault. There shall not be openings in the vault enclosure except those necessary for vault ventilation and access, inspection, filling, emptying or venting of equipment in the vault. The walls and floor of the vault shall be constructed of reinforced concrete not less than 6 inches (152 mm) thick. The top of an above-grade vault shall be constructed of noncombustible material and shall be designed to be weaker than the walls of the vault to ensure that the thrust of any explosion occurring inside the vault is directed upward.
The top of an at- or below-grade vault shall be designed to relieve safely or contain the force of an explosion occurring inside the vault. The top and floor of the vault and the tank foundation shall be designed to withstand the anticipated loading, including loading from vehicular traffic, where applicable. The walls and floor of a vault installed below grade shall be designed to withstand anticipated soil and hydrostatic loading. Vaults shall be designed to be wind and earthquake resistant, in accordance with the California Building Code.
Compressed gas containers, cylinders and tanks, except those designed for use in a horizontal position, and all compressed gas containers, cylinders and tanks containing nonliquefied gases, shall be stored in an upright position with the valve end up. An upright position shall include conditions where the container, cylinder or tank axis is inclined as much as 45 degrees (0.80 rad) from the vertical.
- Compressed gas containers with a water volume less than 1.3 gallons (5 L) are allowed to be stored in a horizontal position.
- Cylinders, containers and tanks containing nonflammable gases, or cylinders, containers and tanks containing nonliquefied flammable gases that have been secured to a pallet for transportation purposes.
Compressed gas containers, cylinders and tanks, except those designed for use in a horizontal position, and all compressed gas containers, cylinders and tanks containing nonliquefied gases, shall be used in an upright position with the valve end up. An upright position shall include conditions where the container, cylinder or tank axis is inclined as much as 45 degrees (0.80 rad) from the vertical. Use of nonflammable liquefied gases in the inverted position where the liquid phase is used shall not be prohibited provided that the container, cylinder or tank is properly secured and the dispensing apparatus is designed for liquefied gas use.
Exception: Compressed gas containers, cylinders and tanks with a water volume less than 1.3 gallons (5 L) are allowed to be used in a horizontal position.
Transfer of gases between containers, cylinders and tanks shall be performed by qualified personnel using equipment and operating procedures in accordance with CGA P-1.
Exception: The fueling of vehicles with CNG or CH2, conducted in accordance with Chapter 23.
Gas cabinets shall be constructed in accordance with Section 5003.8.6 and the following:
- The average velocity of ventilation at the face of access ports or windows shall be not less than 200 feet per minute (1.02 m/s) with not less than 150 feet per minute (0.76 m/s) at any point of the access port or window.
- They shall be connected to an exhaust system.
- They shall be internally sprinklered.
Mechanical ventilation shall be in accordance with the California Mechanical Code and shall comply with all of the following:
- Mechanical ventilation in the room or area shall be at a rate of not less than 1 cubic foot per minute per square foot [0.00508 m3/(s • m2)].
- Exhaust shall be taken from a point within 12 inches (305 mm) of the floor.
- The ventilation system shall be designed to operate at a negative pressure in relation to the surrounding area.
An emergency alarm system shall comply with all of the following:
- Continuous gas detection shall be provided to monitor areas where carbon dioxide can accumulate.
- The threshold for activation of an alarm shall not exceed 5,000 parts per million (9,000 mg/m3).
- Activation of the emergency alarm system shall initiate a local alarm within the room or area in which the system is installed.