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Explosion-Proof Refrigerators and
Freezers
Overview
The Authority Having Jurisdiction (AHJ) determines if work
areas are designated as a hazardous location with respect to
the presence of flammable gases or vapors. Such locations
are defined in (National Fire Protection Agency) NFPA 70
Articles 500- 501, OSHA 29 CFR1910.307 and NFPA 45.
Some of these classified areas are expected to experience
concentrations of flammable gases and/or vapors at or above
their lower flammability limits for extended periods of time.
The construction of our Explosion-Proof Refrigerators and
Freezers has been evaluated by Underwriters Laboratories
(UL) and are suitable for use in classified areas requiring Class
I, Groups C and D* protected equipment. The electrical
components such as thermostats, wiring, splices, relays and
compressor motors on Explosion-Proof Refrigerators and
Freezers are safely housed within Explosion-Proof enclosures
and conduit. Compressor surface temperatures have been
evaluated and determined to remain below the flash point of
materials found in Class I, Groups C and D. All models have
heavy-gauge, rigid, steel construction with a durable enamel
finish. Interiors have epoxy enamel or ABS plastic
construction. Each unit is insulated throughout for energy-
efficient operation.
These units are designed to meet the standards established
by Underwriters' Laboratory, Inc., OSHA and National Fire
Protection Association for storage of hazardous materials.
On Explosion Proof Refrigerators and Freezers all ferrous
flame paths are protected from corrosion by the use of
petroleum jelly (or petrolatum or soap-thickened mineral oils).
It is important to note that Explosion-Proof Refrigerators and
Freezers must be connected to the power supply source by
rigid metal conduit with proper fittings suitable for Class I,
Groups C and D* hazardous locations.In addition, the wires
inside the conduit must be sealed. Explosion-Proof
Refrigerators and Freezers require being hard wired into the
building electrical system and therefore require a qualified
electrician to install as per the "local electrical requirements
and NEC Standard" or "Canadian Electrical Standard".
*The notation Class 1, Groups C and D is an accepted
abbreviation for Class I, Div 1, Groups C and D; Class I Zone
1 Group IIB.
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Flammable Material Storage and Explosion Proof Laboratory Refrigerators and Freezers
WARNING: For Explosion-Proof Refrigerators
and Freezers where flammable materials are
stored in the cooling chamber, the cooling
chamber is considered a Class I Div1 or Class I
Zone 1 hazardous location. Any monitoring
devices placed in the cooling chamber must have
an intrinsically safe rating from an appropriate
certification body, such as UL, CSA, FM etc. (this
includes battery or solar powered devices).
Thermocouples for building monitoring systems must be
wired through an electrical barrier designed to provide
isolation against voltage and current spikes, which could
cause a spark resulting in fire or explosion. It is the your
responsibility to meet these requirements. Thermo Scientific
cannot assist with the selection of devices, recommend,
approve or design any device or monitoring circuit.
Thermo Scientific reserves the right to change specifications
without prior notice.
Note: If any questions pertaining to electrical safety arise,
please refer to article 501 of the US National Electrical Code.
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