Table of Contents
What are the four groups of the NEC?
The gases and vapors of Class I locations are broken into four groups by the Code: A, B, C, and D. These materials are grouped according to the ignition temperature of the substance, its explosion pressure, and other flammable characteristics.
What are the classification of electrical area?
Class (material type) 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 is a Class I location NEC?
Class I Locations A “Class I Location” is created by the presence of flammable gases or vapors in the air in sufficient quantities to be explosive or ignitable. When these materials are found in the atmosphere, a potential for explosion exists if an electrical or other source of ignition is present.
What is a Class 1 Division 2 environment?
Class I Hazardous Locations refer to facilities which deal with flammable gases, vapors, and liquids. Division 2 specifies that these flammable materials are handled, processed, or used in the defined hazardous location, but are not normally present in concentrations high enough to be ignitable.
What is a Class 2 location?
Class II Locations The second type of hazardous location is called a “Class II Location”. This classification is created by the presence of combustible dust in the air in sufficient quantities to be explosive or ignitable.
Is gas Group IIC better than IIB?
Any equipment which is marked as IIC can be used in atmospheres that contain Group IIB and Group IIA gasses. Conversely equipment marked IIA cannot be used in IIB or IIC explosive environments….Gas Groups.
| GAS GROUPS | TYPICAL GAS EXAMPLE |
|---|---|
| IIB | Coke Oven Gasses, Ethylene |
| IIC | Acetylene, Carbon Disulphide, Hydrogen |
Which is better T1 or T6?
Suitable Equipment A T Class rating of T1 means the maximum surface temperature generated by the instrument at 40° C is 450° C. A rating of T6 means the maximum surface temperature generated by the equipment is 85° C.
What is T rating in hazardous area?
Temperature class (also known as ‘T-rating’) defines the explosion hazard type for the Ex product. The class, from 1 to 6, indicates the highest temperature allowed without igniting anything in the area. Class defines risks of a zone in a given area.
What is temperature class T1 to T6?
A classification of T1 means the minimum ignition temperature is >450° C [842° F]. A classification of T6 means the minimum ignition temperature is >85° C [185° F].