As these flammable refrigerants take hold around the globe, the IFC, in its 2024 edition, has specified storage quantities in
- Group M occupancy,
- in an outdoor control area or
- stored in a single control area of a Group S occupancy.
5003.11.2 Category 1B flammable gas with low burning velocity.
The aggregate quantity of Category 1B flammable gas having a burning velocity of 3.9 in/s (10 cm/s) or less stored and displayed within a single control area of a Group M occupancy, in an outdoor control area or stored in a single control area of a Group S occupancy shall not exceed the amounts set forth in Table 5003.11.2.
| TABLE 5003.11.2 MAXIMUM ALLOWABLE QUANTITY OF LOW BURNING VELOCITY CATEGORY 1B FLAMMABLE GAS IN GROUP M AND S OCCUPANCIES PER CONTROL AREAa | ||
| CATEGORY 1B (Low BV)d | SPRINKLERED IN ACCORDANCE WITH NOTE B | NONSPRINKLERED |
| Gaseous | 39,000 ft3 | 195,000 ft3 |
| Liquefied | 40,000 lbc | 20,000 lb |
| For SI: 1 pound = 0.454 kg, 1 cubic foot = 0.028 m3. a. Control areas shall be separated from each other by not less than a 1-hour fire barrier. b. The building shall be equipped throughout with an approved automatic sprinkler system with a minimum sprinkler design density of Ordinary Hazard Group 2 in the area where flammable gases are stored or displayed. c. Where storage areas exceed 50,000 square feet in area, the maximum allowable quantities area is allowed to be increased by 2 percent for each 1,000 square feet of area in excess of 50,000 square feet, up to not more than 100 percent of the table amounts. Separation of control areas is not required. The aggregate amount shall not exceed 80,000 pounds. d. “Low BV” Category 1B flammable gas has a burning velocity of 3.9 in/s (10 cm/s) or less. | ||
5003.11.2.1 Fire protection and storage arrangements.
Fire protection and container storage arrangements for quantities of Category 1B flammable gases permitted by Table 5003.11.2 shall be in accordance with the all of the following:
- Storage of Category 1B flammable gases on shelves shall not exceed 6 feet (1829 mm) in height, and shelving shall be metal.
- Rack storage, pallet storage or piles of Category 1B flammable gas greater than 6 feet 6 inches (1981 mm) in height shall be provided with an automatic sprinkler system with a minimum design density of Extra Hazard Group 1.
- Combustible commodities shall not be stored above Category 1B flammable gases.
- Flammable liquids shall be separated from Category 1B flammable gases by a distance of not less than 20 feet (6096 mm). The separation is permitted to be reduced to 10 feet (3048 mm) where secondary containment or diking is provided to retain a flammable liquid spill at a distance of 10 feet (3048 mm) from the Category 1B flammable gas storage.