Storing Flammable in Freezer

Chem E

I would appreciate some information on applicable NEC, NFPA, or ??? codes that apply to the following situation.
The company fills 6 gallon plastic containers with a flammable liquid. The containers are filled in a Class 1 Div 1 area where they are sealed. The containers are UN rated for air transport and sealed using calibrated torque wrenches per the container’s manufacturers recommendations. The flammable containers are stored in freezers in a different room in a different area of the complex. The room is general purpose and only houses freezers used for these materials. The room is located on an outside wall of the complex. The freezers being used operate in the -30 to -80°C range and are stored in freezers for product quality issues. The filled containers are removed from the freezers for air shipment around the world. I have confirmed with the relevant authorities including the DOT that the air shipment of these plastic containers with flammable liquids is legal and acceptable in every way since the containers are UN rated and have the applicable certifications, etc. Once the plastic shipping container is sealed in the Class 1 Div 1 area it is not re-opened until it reaches the customer’s facility.
My question is: Are there any formal requirements for the freezers used to store the containers? NFPA 45 references freezers, but that is in a lab environment, which this is not. NFPA 30 505.5 references freezers in an Information Note that states: “This classification (Zone 1) usually includes locations where……; the interiors of refrigerators and freezers in which volatile flammable materials are stored in the open, lightly stoppered, or in easily ruptured contain.” The containers being stored are tightly sealed and difficult to rupture, so this statement doesn’t apply.
I’m not really interested in getting into a discussion as to whether it is safe or not to use a general purpose freezer. I’ll respect your opinion either way. What I am looking for is a requirement by a relevant recognized authority that is applicable to the above situation. Thanks for any help.


Staff member
My question is: Are there any formal requirements for the freezers used to store the containers? ...
Nothing much beyond the NFPA material you have already cited. Sealed containers, stored and/or transported properly, do not create a need to classify a location.
You may want to review relevant DOT Standards for safe transport,