| HIGHER FLAMMABILITY |
A3 R-50, R-170, R-290 R-600a, R-441a, R-1270 |
B3 R-1140 |
| LOWER FLAMMABILITY |
A2 R-142b, R-152a |
B2 R-30, R-40, R-611, R-717
|
|
A2L HFO-1234yf, HFO-1234ze |
||
| NO FLAME PROPAGATION |
A1 R-11 – R-14, R-22, R-113, R-114, R-115, R-134A, R-410A, R-449B, R-1234zd |
B1 R-10, R-21, R-123, R-764 |
|
LOWER TOXICITY |
HIGHER TOXICITY |
A2L flammable refrigerants have been written into the 2024 Fire Code, Mechanical Code, and Building Code. A2L refrigerants have lower flammability and toxicity than other classifications
A = non-toxic, 2 = flammable, L = low burning velocity — making it the second-safest refrigerant category.
Cylinder Storage Requirements:
| Characteristic | Shelf Storage |
Pallet Rack Storage |
Pile |
| Design |
The shelf cannot exceed 30″ from front to back |
Each Level is designed to hold a pallet load | Pallets stacked one upon another |
| Construction Materials | Steel | Steel | N/A |
| Storage Height | Maximum 6′ to top of storage | Can exceed 6′ when allowed by sprinkler design | Can exceed 6′ when allowed by sprinkler design |
| Sprinkler System |
Ordinary Hazard Group 2 |
Extra Hazard Group 1 |
Extra Hazard Group 1 |
| Separation from Flammable Liquids | REQUIRED | REQUIRED | REQUIRED |
| Storage of Flammables & Combustibles ABOVE A2Ls | PROHIBITED | PROHIBITED | PROHIBITED |
| Storage of Flammable Liquids Adjacent to A2Ls |
20′ minimum separation |
20′ minimum separation |
20′ minimum separation |
| Storage of Flammable Liquids w/ Secondary Containment Adjacent to A2Ls |
10′ separation to containment |
10′ separation to containment |
10′ separation to containment |
A building protected with fire sprinklers can include 1-hour fire-resistant-rated walls to create four (4) separate control areas.
Each control area can store up to 40,000 lbs. of liquefied Group A2L refrigerants.
| Maximum Allowable Quantity (MAQ) in a Control Area | ||
| Occupancy Classification | NON-SPRINKLED | SPRINKLED |
| Liquified Gas in Cylinders | Liquified Gas in Cylinders | |
| M – Mercantile | 20,000 pounds | 40,000 pounds |
| S – Storage | 20,000 pounds | 40,000 pounds |
| F – Factory and Filling Facility | 10,000 pounds | 20,000 pounds |
| Shelf | Rack | Pile |
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 |
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