What are flammable material and explosion proof refrigerators?

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Earlier this week one of our technicians was giving a few of his family members a tour of the shop, showing off his work. At the time he was in the midst of testing and inspecting a flammable material storage freezer. “Why would anyone need to store something flammable in a lab?” one of the kids asked. So in recognition of that question we figured we’d put together a little primer on flammable material fridges and freezers.

Many labs work with solvents and intermediates that are volatile and must be chilled or frozen and thus require storage solutions that reduce the risk of fire. Standard laboratory refrigerators and domestic refrigerators have numerous ignition sources that could ignite accumulated vapors: electrical and heating components in standard refrigerators and freezers are typically exposed and can cause a spark leading to a fire or an explosion.

So what’s the solution for storing temperature sensitive volatile materials?

Specialized cold storage with no interior ignition sources. Flammable material refrigerators and freezers have no interior sparking lights, thermostats, defrost timers, switches, or any other electrical components located in the interior of the unit. All electrical components, such as temperature controller and other wiring, must be located on the exterior of the unit.

Explosion-proof refrigerators and freezers are designed to prevent triggering a fire or an explosion both inside and outside the unit. All of the electrical components and wiring (including temperature controller, evaporator, etc.) are located in sealed conduit housings on the exterior of the unit.  The unit does not come with a power cord and must be hard-wired to the power source, successfully eliminating any electrical exposure.

An example of a flammable material storage freezer is this Fisher Isotemp unit. It’s built to preserve temperature sensitive reagents, samples and specimens. The spark-proof interior separate contents from compressor and motor and it features a top-mounted hydraulic thermostat and door stop and magnetic door gaskets that provide airtight seals that insulate and prevent release of hazardous fumes.

This flammable material storage refrigerator from American Biotech Supply is similar in design but with a temperature range from 0°C to 10°C.

For an explosion proof freezer option is this Fisher model, with a top-mounted hydraulic explosion-proof thermostat and 1/3 horsepower hot wall condenser compressor. To comply with NEC code these units must be hard wired directly into a properly rated conduit box. This unit has a temperature range down to -30°C and about 30 cubic feet of storage capacity.

(And quick disclaimer: we’re happy to provide additional information on any of the equipment we have in stock, but you should always double-check with your facilities manager, landlord, or other safety supervisor for specific storage guidelines for your lab or building.)  

So if you’re in the market for either flammable material or explosion proof cold storage and are looking to save some money, please give us a call or email today. Our prices are typically 40% – 60% lower than comparable new units and all of our equipment come fully tested to manufacturer spec and with a warranty. Thanks! American Instrument Exchange has been a reliable source for used laboratory and scientific equipment for over 50 years, buying and selling equipment since 1969. Our surplus lab equipment is reconditioned for many types of laboratories, including biotech, biomedical, medical research, chemical, pharmaceutical, and university and hospital research laboratories. All lab equipment listed on our website is in stock and ships from our 30,000 square foot warehouse in Massachusetts. Our facilities include a fully equipped shop with highly trained technicians who thoroughly test each instrument before it reaches your laboratory. Please visit our website at https://www.americaninstrument.com/.