Heads up: There are no amended sections in this chapter.
The storage and use of flammable gases and flammable cryogenic fluids shall be in accordance with this chapter and NFPA 55. Compressed gases shall also comply with Chapter 53 and cryogenic fluids shall also comply with Chapter 55. Flammable cryogenic fluids shall comply with Section 5806. Hydrogen motor fuel-dispensing stations and repair garages and their associated above-ground hydrogen storage systems shall also be designed and constructed in accordance with Chapter 23.
- Gases used as refrigerants in refrigeration systems (see Section 606).
- Liquefied petroleum gases and natural gases regulated by Chapter 61.
- Fuel-gas systems and appliances regulated under the International Fuel Gas Code other than gaseous hydrogen systems and appliances.
- Pyrophoric gases in accordance with Chapter 64.
Flammable gases shall not be stored or used in Group A, E, I or R occupancies or in offices in Group B occupancies.
- Cylinders of nonliquefied compressed gases not exceeding a capacity of 250 cubic feet (7.08 m3) or liquefied gases not exceeding a capacity of 40 pounds (18 kg) each at normal temperature and pressure (NTP) used for maintenance purposes, patient care or operation of equipment.
- Food service operations in accordance with Section 6184.108.40.206.
Static-producing equipment located in flammable gas storage areas shall be grounded.
Electrical wiring and equipment shall be installed and maintained in accordance with Section 605 and NFPA 70.
Containers of liquefied flammable gases and flammable gases in solution shall be positioned in the upright position or positioned so that the pressure relief valve is in direct contact with the vapor space of the container.
The vacuum jacket used as an outer vessel for storage tanks in liquid hydrogen service shall be of welded steel construction designed to withstand the maximum internal and external pressure to which it will be subjected under operating conditions to include conditions of emergency pressure relief of the annular space between the inner and outer vessel. The jacket shall be designed to withstand a minimum collapsing pressure differential of 30 psi (207 kPa).
A connection shall be provided on the exterior of the vacuum jacket to allow measurement of the pressure within the annular space between the inner and outer vessel. The connection shall be fitted with a bellows-sealed or diaphragm-type valve equipped with a vacuum gauge tube that is shielded to protect against damage from impact.
Storage tanks shall be located outside in accordance with the following:
- Tanks and associated equipment shall be located with respect to foundations and supports of other structures such that the loads carried by the latter cannot be transmitted to the tank.
- The distance from any part of the tank to the nearest wall of a basement, pit, cellar or lot line shall not be less than 3 feet (914 mm).
- A minimum distance of 1 foot (305 mm), shell to shell, shall be maintained between underground tanks.
The tank shall be buried such that the top of the vacuum jacket is covered with a minimum of 1 foot (305 mm) of earth and with concrete a minimum of 4 inches (102 mm) thick placed over the earthen cover. The concrete shall extend a minimum of 1 foot (305 mm) horizontally beyond the footprint of the tank in all directions. Underground tanks shall be set on firm foundations constructed in accordance with the International Building Code and surrounded with at least 6 inches (152 mm) of noncorrosive inert material, such as sand.
Exception: The vertical extension of the vacuum jacket as required for service connections.
The vacuum jacket shall be designed and constructed in accordance with Section VIII of ASME Boiler and Pressure Vessel Code and shall be designed to withstand the anticipated loading, including loading from vehicular traffic, where applicable. Portions of the vacuum jacket installed below grade shall be designed to withstand anticipated soil, seismic and hydrostatic loading.
The vacuum jacket shall be protected by approved or listed corrosion-resistant materials or an engineered cathodic protection system. Where cathodic protection is utilized, an approved maintenance schedule shall be established. Exposed components shall be inspected at least twice a year. Maintenance and inspection events shall be recorded and those records shall be maintained on the premises for a minimum of three years and made available to the fire code official upon request.
An approved method shall be provided to indicate loss of vacuum within the vacuum jacket(s).
Metal hydride storage systems shall be marked with the following.
- Manufacturer's name;
- Service life indicating the last date the system can be used;
- A unique code or serial number specific to the unit;
- System name or product code that identifies the system by the type of chemistry used in the system;
- Emergency contact name, telephone number or other contact information; and
- Limitations on refilling of containers to include rated charging pressure and capacity.
Cylinders, containers and tanks used in metal hydride storage systems shall be marked with the following:
- Manufacturer's name;
- Design specification to which the vessel was manufactured;
- Authorized body approving the design and initial inspection and test of the vessel;
- Manufacturer's original test date;
- Unique serial number for the vessel;
- Service life identifying the last date the vessel can be used; and
- System name or product code that identifies the system by the type of chemistry used in the system.
Metal hydride storage systems shall not be placed in areas where they are capable of being damaged by falling objects.
Piping, including tubing, valves, fittings and pressure regulators, serving metal hydride storage systems, shall be maintained gas tight to prevent leakage.
The purity of hydrogen used for the purpose of refilling containers shall be in accordance with the listing and the manufacturer's instructions.
Electrical components for metal hydride storage systems shall be designed, constructed and installed in accordance with NFPA 70.
Metal hydride storage systems used on motorized equipment, shall be installed in a manner that protects valves, pressure regulators, fittings and controls against accidental impact.