What are the classification of electrical area?
Class I: Denotes areas where flammable gas, vapor, or liquid is present. Class II: Denotes areas where combustible dust is present. Class III: Denotes areas where ignitable fibers are present. (Class III areas rarely exist in CTG facilities.)
What are the classification of electrical hazardous location?
Let’s quickly review. The National Electric Code classifies hazardous locations in three ways: TYPE, CONDITION, and NATURE. There are three types of hazardous conditions: Class I – gas and vapor, Class II dust, and Class III – fibers and flyings.
What are the three NEC hazardous area classifications?
Hazardous locations are classified by three different criteria type, condition, and nature.
What does Zone 22 mean?
ATEX Zone 22 Definition – What is Zone 22? A Zone 22 area is classified as an atmosphere where a mixture of air and flammable substances in the form of powder or dust is not likely to occur in normal operation, but if it does occur, will persist for a short period only.
How do you classify hazardous areas?
Those areas where the possibility or risk of fire or explosion might occur due to an explosive atmosphere and/or mixture is often called a hazardous (or classified) location/area. Currently there are two systems used to classify these hazardous areas; the Class/Division system and the Zone system.
What is NFPA 497a hazardous electrical area classification?
Currently undergoing extensive revision, this standard is to be replaced by NFPA 497A, Recommended Practice for the Classification of Class I Hazardous (Classified) Location for the Proper Installation of Electrical Equipment in Chemical Process Areas.
What are the parameters for electrical area classification?
Before going to the step -by-step method for performing electrical area classification, it should be explained that a classified (hazardous) area is defined by three parameters; these being 1) class, 2) group, and 3) division.
How does the Hazardous Area Classification system work?
The hazardous area classification system determines required protection techniques and methods for electrical installations in the location. The Class/Division/Group system is based on Article 500 of the National Electrical Code (NEC) where Classes – defines the general nature of the hazardous material in the surrounding atmosphere
How are hazardous areas defined in electrical codes?
Hazardous area classification is a rigorous method of determining where an explosive environment may be present. The codes and standards used in this process provide guidance for selecting, building, and installing electrical equipment in that area. In general, hazardous areas (HAs) are defined by: