Flame Resistant Pants, or FR Pants, are usually one piece of a larger Personal Protective Equipment (PPE) kit for workers who are exposed to potential arc flash situations.
Along with an FR shirt, hood and/or faceshield, gloves and boots, FR pants are usually chemically treated to reduce the heat and blast of arc flash, and will not have any metal fasteners or zippers – as those can become molten shrapnel during a blast. The material is generally a treated cotton or non-melting fabric, designed not to fuse into the skin like some nylon polyester blends.
Like all FR rated clothing, FR Pants come in different levels of protection, from as little as 5 calories per square centimeter to 40 ca/cm2 and higher.
There are now strict requirements for electrical workers to use proper PPE to meet arc flash standards, set out in the National Fire Protection Association standard 70E (in Canada, it is
CSA Z462). FR pants are but one component of PPE, required by workers to wear when exposed to the threat of an arc flash incident.
NFPA 70E establishes Hazard or Risk categories, with the minimum Arc Thermal Performance Value (ATPV). (Cal/cm2 stands for calories per square centimeter).
The following minimum ATPV in less than cal/cm are for category 2 and higher:
Category 2
Requires 8 cal/cm2 ATPV
Category 3
Requires 25 cal/cm2 ATPV
Category 4
rRequires 40 cal/cm2 ATPV
For all of these categories, arc flash rated FR pants are required.
Some of the considerations when purchasing FR pants are fabric weight and the heat attenuation factor (HAF). Fabric weight is represented in both US measure and metric: ounces per square yard or grams per square meter.
The HAF is the amount of heat blocked by the fabric, as flame resistance and HAF are two different properties. A fabric may be 100 per cent flame resistant, but might be only 85 per cent capable of blocking the heat.
Naturally the higher the risk faced by a worker, the heavier the material will be to meet the heat and blast from potential arc flash situations.
The various standards dealing directly with arc flash safety include:
- OSHA Standards 29-CFR, Part 1910. Occupational Safety and Health Standards. 1910 sub part S (electrical) Standard number 1910.333 specifically addresses Standards for Work Practices and references NFPA 70E
- The National Fire Protection Association (NFPA) Standard 70 - “The National Electrical Code” (NEC) contains requirements for warning labels
- NFPA 70E provides guidance on implementing appropriate work practices that are required to safeguard workers from injury while working on or near exposed electrical conductors or circuit parts that could become energized
- The Canadian Standards Association's CSA Z462 Arc Flash Standard is Canada's version of NFPA70E
- The Institute of Electronics and Electrical Engineers IEEE 1584 – Guide to Performing Arc-Flash Hazard Calculations
Read More Here: Arc Flash and Electrical Safety
- Read More Here: Electrical Safety Training
- Read More Here: Electricity
For more information, see:
Electrical Safety OSHA
Electrical Safety Workplace
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