Wednesday, July 24, 2019

What is Class I Division 2?

A Class I Division 2 is a location: (1) In which volatile flammable gases, flammable liquid-produced vapors, or combustible liquid-produced vapors are handled, processed, or used, but in which the liquids, vapors, or gases will normally be confined within closed containers or closed systems from which they can escape only in case of accidental rupture or breakdown of such containers or systems or in case of abnormal operation of equipment, or (2) In which ignitable concentrations of flammable gases, flammable liquid-produced vapors, or combustible liquid-produced vapors are normally prevented by positive mechanical ventilation, and which might become hazardous through failure or abnormal operation of the ventilating equipment.

Class I Division 2 Classification

Class I Division 2 refers to the ANSI/ISA 12.12.01 standard. This standard was previously UL1604 until UL recommended the newer ANSI/ISA standard be used and that all hazardous location products be certified under this standard by July 2012.

What is class 1 div 2



This standard applies only to equipment, circuits, and components designed specifically for use in Class I and II, Division 2 and Class III, Divisions 1 and 2 hazardous locations as defined by the National Electrical Code (NEC) ASI/NFPA 70.

Within the ANSI/ISA 12.12.01 standard. There are two types of hazardous conditions are 3 different classes and 2 divisions within each class. For a Class I rating the 2 divisions are Division 1 - normal conditions and Division 2 - abnormal conditions.

The CSA hazardous location certification is C22.2 No. 213-M1987-Non-Incendive Electrical Equipment for Use in Class I Division 2 Hazardous Locations.

What is a hazardous location?

According to the NEC and the Canadian Electrical Code (CEC) a hazardous location is defined as areas "where fire or explosion hazards may exist due to flammable gasses or vapors, flammable liquids, combustible dust, or ignitable fibers or flyings." Specifically, Class I Division 2 refers to only flammable gasses or vapors.

Furthermore, hazardous locations are locations where electrical equipment could be installed and might present a condition which could become explosive if the right elements for an ignition would be present. Hazardous material is expected to be found within closed containers and/or systems and would be present only if an accidental rupture, breakage or an unusual faulty operation would occur, leading the situation to be abnormal, the Division 2 rating.

An example of a normal condition would be where hazardous material would be present during normal plant operations, which coincides with the Division 1 rating.

This hazardous material could ignite through arcs and sparks, high temperature, and electrical
equipment failure.

This means that any product with a Class I Division 2 rating must contain an explosion within, provide a way for the burning gases to escape after the flames are quenched through a flame path.

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