Refrigerator stories, July 2000:

The stories below came to a safety listserv in response to a query from Richard Benton, Fire Marshal at the University of California, San Diego:  "Does anyone have direct knowledge of instance(s) of fires involving flammable liquids stored in either cold rooms or refrigerators other than full-on explosion-proof units?  We are constantly challenged by our faculty as to why we won't let them use commercial (home-type) refrigerators, nor allow them to try to field-modify such units to eliminate (their idea) all hazards."

Note:  I'm not sure I'd call it "field-modification" but here at Purdue we do allow in-house modification of refrigerators and freezers by the Physical Facilities Refrigeration Shop.  They remove the light wiring and move the thermostat to the exterior of the unit.  It costs around $150 or so at latest inquiry, and it is my understanding that this renders the unit adequately "flammable-safe."  You must still keep containers of flammables CLOSED SECURELY.  And IT VOIDS YOUR WARRANTY, of course.  If this is not acceptable you must simply purchase a flammable safe unit from a manufacturer.   Self defrosting freezer units are not modifiable (I think).

THE Responses:

From Penn State:  
One of our labs experienced an explosion and fire resulting from the temporary storage of solution samples (alcohol / ethanol etc.) in a non-explosion proof refrigerator.  The amount of materials placed in the refrigerator was very small.  One lab was conducting some house cleaning and an individual placed the solutions in another labs refrigerator thinking it was explosion proof.  Fortunately, no one was in the lab when the explosion occurred.  The loss due to the explosion, fire and smoke was around $200,000 in addition to the time the lab was unable to be used during renovation and cleanup. 

From U Colorado:
Here at the University of Colorado Health Sciences Center, we have not experienced any incidents of flammable liquid fires due to storage in cold rooms or standard refrigerators (even though we know some researchers are doing it).  Regardless, has always been campus policy that flammable liquids may only be stored in approved "explosion-proof" units.  We also have had researchers question the rationale behind the policy.  Since the nature of research often requires the lab to use cooled material, we recently decided to allow an exception for limited quantities (500 ml) in sealed plastic containers (with a 25% vapor space for expansion) and provided that secondary non-breakable containment is used.  With these safeguards, it is difficult to imagine a fire/explosion.  [LAS note -- in regular household units?!  This sounds like a really bad idea.]

From U Virginia:
At the University of Virginia we have found out the hard way.  Two and a half years ago we had an incident in a Chemistry Lab using a household refrigerator.  Vapor from stored chemicals exploded inside the refrigerator, ripping off the door and activating the sprinkler system.  We believe the explosion occurred when the volatile gases came in contact with the electrical arc in the normal operation of the defrost timer housing.  We were lucky that no one was hurt.  We had claims in excess of $100,000

We have since removed all household type refrigerators that were being used for storage of flammable compounds in labs .  We do not recommend the field modified units for this type of storage.  They should be explosion proof type which are hard wired ( not plugged into a receptacle ).  For more info contact me @ Tim Ritchey, UVa Fire Marshal, 804 982-4914, fire-safety@virginia.EDU

More from U Virginia, (on same incident??):
We had an explosion in a lab that could have killed people and burned down a chemistry building.  It took place in a separate room in a new building protected by sprinklers rather that in the old lab where it would have been in the lab with people and no sprinkler system. I have pictures (digital) that I can send if you would like. They sure helped convince our faculty. We had solvent stills in the room but they were a new safer type and that has also convinced people that these are worth the money as they suvived the explosion.

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Thermostat inside, left side, caused spark. Refrigerator and freezer compartment doors blown off Freezer compartment interior melted panel ripped off
mess mess mess
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From U Maryland:
About 12-15 years ago, we had a series of "I told you so" incidents involving non-approved refrigerators used to store flammable solvents.  The department involved had been told not to purchase or use these residential type refrigerators that had come from the state surplus property unit.

One day, one of the refrigerators experienced an explosion that ripped off one of the hinges and increased the interior capacity by pushing the walls & top out about 6-8 inches.  One would think that the PI would have gotten the message but about a month later, a second explosion occurred in the same suite of labs.

In this one, the door actually came off, exited thru a window, and landed in the parking lot, 3 stories down.

In another lab, a month later, a similar incident occurred at 3AM, less explosion, more fire.  Totally gutted the entire lab and sent several fire fighters to the hospital.  The exact material was never determined (too many burned & broken bottle in the debris).  We were very fortunate that the fire did not involve the six 5-gal cans of ether that were sitting within a few feet of the refrigerator (the cans bulged but didn't fail).

Right after this, the U. made a mass purchase of approved refrigerators & freezers and flammable liquid storage cabinets - and funded complete retrofit of automatic sprinklers in several major lab buildings.

Stick to your guns - there are too many things that can cause the spark necessary for a solvent explosion in these non-approved refrigerators - thermostats, motors, switches, lights, etc.  The only way to safely field modify them is to take out all of these things and put a block of dry ice inside.

From private sector, on use of "lab safe," flammable refrigerator," and "explosion proof."
I have noticed many references in a recent thread regarding explosion-proof refrigerators. This generic term is often used to describe two types of refrigerators used in laboratories.

Remember that there are two types of refrigerators approved for use in storage of flammable liquids or gases.

Explosion proof refrigerators are designed for use in an area where flammable vapors or gases may be present in the environment around the unit.  They have explosion-proof electrical equipment and junction boxes and must be hard-wired into the buildings electrical system using approved methods.  These units are usually quite expensive.

Flammable-safe refrigerators have specially designed interior parts to prevent flammable vapors or gases from contacting internal ignition sources.  They are not approved for use in an environment where flammable vapors or gases may be present, because ignition sources on the exterior of the refrigerator may not be vapor-tight.  These units are connected to an electrical outlet using a standard cord and plug assembly.

Flammable-safe refrigerators are usually much less expensive than explosion-proof models.  Specifying an explosion-proof refrigerator in a lab where flammable vapors won't be present in ignitable quantities may be a waste of funds that may be applied elsewhere.  Specifying a flammable-safe refrigerator in a lab where flammable vapors are present may result in an ignition, fire, or explosion.

Laboratory personnel frequently ask for an explosion-proof refrigerator when only a flammable-safe model is needed. Of course, all lab refrigerators should be labeled as to suitability for flammable storage.