EXAIR’s HazLoc Cabinet Cooler Systems have been set apart from the competition by achieving the UL classified designation for Div 1 environments. Thermostatically controlled systems are recommended for the highest efficiency and include UL-listed solenoids, also for hazardous environments. EXAIR Cabinet Cooller systems will install on your purged enclosure in minutes, require little to no maintenance and operate under the roughest of industrial conditions. If you require low cost, ease of use and reliability, a HazLoc Cabinet Cooler system will meet your needs.
In the United States, the National Electrical Code (NEC) defines these areas in a system of Classes, Divisions, and Groups, depending on the nature of the material that presents the hazard (Class), whether it normally exists or if it’s just possible in abnormal situations (Division), and the specific type of the subject material (Group). Today’s blog is all about what would classify an area as Class I, Division 1, and which Group the specific hazardous material falls under.
A Class I location means that the hazard is a flammable gas or vapor which is present in the area in a high enough concentration to be considered ignitable. These were the locations that we were required to use non-sparking tools within, and for good reason. Some examples of Class I locations are:
- Petroleum refineries
- Gasoline storage or dispensing areas
- Aircraft hangars and fueling stations
- Spray finishing rooms or booths
Division 1 means that the flammable gas or vapor that makes the area a Class I location is present in the atmosphere during normal operating conditions and/or when the gas or vapor is released to the atmosphere during maintenance or repair work. These gases & vapors aren’t present in ALL areas of the above-listed Class I examples during normal operation, so only the areas where they ARE present during normal operations would be defined as Division 1. For example:
- Areas where a gasoline tank (in a refinery or gasoline storage/dispensing station, for example) is vented to the atmosphere are Class I Division 1, because the vapor coming out of the vent is doing so by design…you can’t pump a liquid into a non-vented tank.
- Only the parts of an aircraft hangar where fuel is actually being handled are Division 1. That wouldn’t necessarily apply to a stock or communications room in the hangar, though.
- The interior of a paint booth is Division 1 because the spray is volatile, as is the immediate vicinity adjacent to an open spray booth.
Class I designation is further divided into four groups, based on two specific characteristics of the gas or vapor that express how easy it is to cause (or how hard it is to prevent) an explosive hazard:
- Maximum Experimental Safe Gap (MESG) – The gas is put in the interior chamber of a vessel with an adjustable gap that leads to the outer chamber. MESG is the largest gap between the chambers that will prevent ignition of the gas.
- Minimum Igniting Current (MIC) ratio. This is the ratio of the minimum current from an inductive spark required to ignite the gas, divided by the minimum current from an inductive spark that will ignite methane under the same conditions.
- Group A: Acetylene
- MESG = 0.25 mm
- MIC ratio = 0.017
- Group B: Hydrogen, butanedione, ethylene oxide, Propylene oxide, and acrolein
- MESG <0.45mm (except acetylene)
- MIC ratio <0.4 (except acetylene)
- Group C: Ethylene, cyclopropane and ethyl ether
- MESG = 0.45mm to 0.75mm
- MIC ratio = 0.4 – 0.8
- Group D: Acetone, ammonia, benzene, butane, ethanol, gasoline, hexanes, methane, methanol, methane, naphtha, natural gas, propane and toluene
- MESG >0.75mm
- MIC ratio >0.8
EXAIR HazLoc Cabinet Cooler Systems are engineered and approved for use on electrical enclosures in these areas, as well as Class II and Class III. Our ATEX Cabinet Cooler Systems are compliant with the European Union’s ATEX Directive (Zones 2 and 22).
Wherever the panel you need cooling for is located, we’ve very likely got a reliable and safe solution. If you’d like to find out more, give me a call.
Jordan Shouse
Application Engineer
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