In the previous blog, we explained what an explosive atmosphere was, and why an Intrinsic Safety Certification is required for your communications headset.
In Part Two we will delve into the Classification System itself and explain how to identify which communication headsets are certified as Intrinsically Safe for the environment you are working in.
Hazardous area classification is used to identify places where, because of the potential for an explosive atmosphere, special precautions over sources of ignition are needed to prevent fires and explosions.
Plants and facilities are typically classified according to:
Equipment is classified according to:
The properties of the materials and the level of risk are assessed to separate the equipment safety ratings into Hazard Classes, Area Classifications (Zones), Gas Groups, and Temperature Class.
Three hazard classes are defined:
Class I: Flammable gases, vapors, or liquids.
Class II: Combustible dusts.
Class III: Ignitable fibers and flyings.
Class | Area Classification | Description |
I | Zone 0 | A place where explosive atmospheres are continually present. |
I | Zone 1 | A place in which an explosive atmosphere is likely to occur in normal operation. |
I | Zone 2 | A place in which an explosive atmosphere is not likely to occur in normal operation, but may occur for short periods. |
Gas Group | Gas |
IIA | Propane |
IIB | Ethylene |
IIC | Acetylene & Hydrogen |
This is normally assessed at an ambient temperature of 40ºC. The Temperature Class code identifies a product's maximum surface temperature.
Temperature Class | Maximum surface Temperature |
1 | 450°C |
2 | 300°C |
3 | 200°C |
4 | 135°C |
5 | 100°C |
6 | 85°C |
The design of the communication headset will determine its Intrinsic Safety rating. The headset will then be labeled with the appropriate Hazard Class, Area Classification (Zone), Gas Group, and Temperature Class.
It is dangerous to make assumptions about the safety of your headset when you are working in explosive atmospheres. It is important to consult an Intrinsic Safety Expert to validate the IS certifications of the products being used in these areas.