| A laboratory refrigerator or lab freezers have an | | | | used to conduct tests. Laboratory refrigerators and |
| obvious and essential function; these units are used | | | | laboratory freezers may be stand-alone, upright units |
| to cool or freeze samples for preservation. Typically, | | | | or may fit under the lab counter. A lab freezer may |
| refrigerators are used to store samples at a | | | | also be fitted with locks to restrict entry, and may |
| temperature between - 5 and 15 degrees Celsius, | | | | even be designed to safely insulate flammable |
| while freezers will normally store samples at a | | | | materials from electrical sparks. Some laboratory |
| temperature between - 25 and - 15 degrees Celsius. | | | | refrigerators and laboratory freezers are also used as |
| Some laboratory freezers are used to store biological | | | | incubators that cycle between a heating period and a |
| samples such as vaccines at a significantly lower | | | | refrigeration period. These types of refrigerators are |
| temperature. Cryogenic freezing is also used in some | | | | often used for culturing and monitoring the growth of |
| laboratories, but requires specialized equipment that is | | | | bacteria. |
| capable of generating and tolerating exceptionally low | | | | Flammable chemicals that require refrigeration must |
| temperatures. Ultra low temperature freezers (usually | | | | only be stored in a laboratory refrigerator that is |
| -50 degrees C and below) commonly use a dual | | | | designed for the safe storage of flammables. A |
| compressor cascade type of system to reach these | | | | flammable liquid is defined as having a flash point of |
| low temperatures. The first compressor is used to | | | | less than 100 degrees F (38 degrees C). Flammable |
| obtain a temperature of around -40 degrees C, after | | | | storage laboratory refrigerators are UL approved for |
| which the second compressor kicks in to achieve the | | | | storage of flammable chemicals; lab freezers are |
| lower temperature that is needed. These lab freezers | | | | often used for this purpose as well. Flammable |
| will be usually be noisier than a -20 degrees C | | | | storage refrigerators have no electrical sparking |
| freezer, create more heat output into the room and | | | | devices, relays, switches or thermostats that could |
| will use more energy. They are also more expensive | | | | ignite flammable vapors inside the cabinet. They may |
| to repair than a standard laboratory refrigerator or | | | | also incorporate design features such as thresholds, |
| freezer if the compressor needs to be replaced, | | | | self-closing doors, magnetic door gaskets and special |
| since this will require a repair technician who | | | | inner shell materials that control or limit the damage |
| specializes in these somewhat exotic compressors. | | | | should a reaction occur within the storage |
| Lab refrigerators and freezers include equipment for | | | | compartment. |
| storing samples and special instrumentation used for | | | | A label stating 'Flammable Materials Refrigerator: Keep |
| conducting experiments requiring precise temperature | | | | fire away' should identify such refrigerators. |
| control. For example, a lab refrigerator can be used | | | | Flammable storage units cannot be placed in a room |
| to set up chromatography apparatus within the | | | | containing explosive vapors, but chemicals that exude |
| refrigerator chamber. | | | | explosive vapors can be safely stored inside them. |
| Refrigeration and freezing equipment is also used for | | | | They are called lab-safe, fire-safe or explosion safe |
| the storage of medical or pharmaceutical supplies. A | | | | refrigerators. These refrigerators are more costly |
| blood bank uses a lab refrigerator to preserve the | | | | than the standard household or even laboratory |
| quality of its blood supply. Laboratory refrigerators | | | | refrigerator for that matter, but they must be used |
| and lab freezers that store blood and blood products | | | | if flammables will be stored in the refrigerator. |
| must meet a variety of regulatory and quality | | | | Explosion proof laboratory refrigerators and lab |
| standards for obvious reasons. They normally come | | | | freezers are rated UL explosion-proof and are similar |
| with an alarm system to warn laboratory personnel | | | | in design to the flammable storage units, but they |
| of an equipment failure. Plasma can be stored frozen | | | | also have all operating components sealed against |
| in a plasma freezer for an extended time period. | | | | entrance of explosive vapors. Electrical junction |
| Since the typical expiration date is one year from the | | | | boxes are also sealed after connections are made. |
| collection date, the problem of maintaining an | | | | These units are approved for storage of volatile |
| adequate blood supply is greatly reduced. Pharmacies | | | | materials in areas with explosive atmospheres and |
| may also use a laboratory refrigerator to store | | | | are the most costly of all types. This type of |
| vaccines, medications and other temperature | | | | refrigerator is only required when storing flammable |
| sensitive compounds. | | | | materials in an area with an explosive atmosphere |
| Laboratory refrigerators and laboratory freezers | | | | such as a solvent dispensing room. An explosion |
| include equipment for freezing blood plasma or other | | | | proof laboratory refrigerator has very limited use on |
| blood products for future use. Some lab freezers are | | | | campus and require special hazardous location wiring |
| used to store enzymes or other biological reagents | | | | rather than simple cord and plug connections. |