Understanding FR

Understanding FR

How Flame Resistant Clothing (FRC) Is Rated and understanding FR

Clothing worn to protect workers from fire is commonly referred to as "FRC" which is the acronym for Flame Resistant Clothing. Safety Smart Gear offers a selection of quality FRC such as lab coats, flame resistant pants, flame resistant shirts, and flame resistant coveralls made in various types of flame resistant materials including Nomex, Indura, Lyocell, Modacrylic and FR Treated Cotton. Industrial, oil, gas and utility workers rely on the protective, live saving safety benefits gained from flame resistant clothing on a daily basis. With understanding FR, the following is an explanation of the three main safety standards for flame protection safety to help you understand how FRC is rated within each industry.

NFPA 2112 / Flash Fire Protection / Flame Resistant Clothing Oil & Gas

The NFPA (National Fire Protection Association) sets the standards for fire safety and has implemented risk categories to properly address the levels of protection required for FR safety in relation to flash fire hazards. Flash fires are fires that can be caused by oil and/or gas ignition. While the oil drilling and gas extraction industries have worked to reduce probability of flash fire incidents, the steps taken have not completely eradicated the existence of flash fire hazards or the burn injuries and fatalities related to these accidents. The proper use of flame resistant clothing greatly increases the possibility of workers surviving flash fire injuries. It can also lessen recovery time for workers after a flash fire occurrence. FRC have been proven to significantly diminish both the degree and healing time of burn injuries to workers in these industries.

NESC / Arc Flash Protection / Electric Utility 

The NESC (National Electrical Safety Code) are standards published by the IEEE (Institute of Electrical and Electronics Engineers) to set the ground rules for safety regarding people that work on or near electric supply, communications lines and associated equipment utilizing electric voltage where arc flash my be possible. The NESC requires that each employer has a responsibility to determine the possible exposure to arc hazards for its employees. Any exposure risk greater than 2 cal/cm2 requires that employees wear required clothing with an arc rating not less than the anticipated level or arc flash energy which is determined by tables within the NESC standards. If you are uncertain about what rating is right for your job you should consult a company safety officer or senior electrical worker to determine the proper level of protection for arc flash. Certain types of meltable fabrics are not allowed due to the possibility of additional burn injuries caused by melted fabric adhering to the skin.

70E / ASTM F1506 / General Industry

The ASTM F1506 (American Society for Testing and Materials) determines specifications related to flame resistant fabric materials in clothing worn by electrical workers exposed to momentary electrical arc flash thermal hazards. These fabrics must meet the following criteria...

  • Garments must meet minimum performance requirements for both knitted and woven fabrics.
  • Thread, bindings and closures used in clothing must not contribute to the severity of the wearers injuries during an electrical arc exposure.
  • Fabric used must not drip. melt or show more than 2 seconds after flame or 6 inches of char length when tested as new or after 25 washings or dry cleaning sessions.
  • Fabric can not have more than 5 seconds after flame duration when tested as received in accordance with ASTM test method F1959
  • FR clothing that conforms to F1506 must carry a label stating Tracking Code, F1506 compliance, manufacturer name, size information, care instructions, fiber content and ATPV (Arc Thermal Performance Value). Additionally, garments having multiple layers in different areas must be designated. Trim, Pockets and Seams are not considered additional layers.

Also See: Flame Resistant Clothing Material Reference

Hazard Risk Categories, or HRC's, are broken down into 4 flash fire protection levels.

HRC 1 HRC 1: Refers to basic surface layer FR protection level. Typically this would be the minimal level of protection and would include an FR shirt, a pair of FR pants or a pair of FR coveralls. The minimum rating for this protection level is 4 calories per cubic centimeter squared, or 4 cal/cm2

HRC 2 HRC 2: Requires a surface layer and base layer FR protection. This level of protection would include an FR shirt and FR pants or a pair of FR coveralls in addition to FR undergarments providing 1 to 2 layers. The minimum rating for this protection level is 8 calories per cubic centimeter squared, or 8 cal/cm2

HRC 3 HRC 3: A base layer including FR undergarments, surface layer including FR shirt, FR pants and FR coveralls combining 2 to 3 layers of protection. The minimum rating for this hazard risk level is 25 calories per cubic centimeter squared, or 25 cal/cm2

HRC 4 HRC 4: Would include FR undergarments, surface layer including FR shirt, FR pants and a multilayer flash suite combining 3 or more layers of protection. The minimum rating for this hazard risk level is 40 calories per cubic centimeter squared, or 40 cal/cm2

ATPV - Arc Thermal Performance Value

HRC - Hazard Risk Category

NESC - National Electrical Safety Code

NFPA - National Fire Protection Association


Flame Resistant Clothing | Flame Resistant Bibs/Overalls | Flame Resistant Shirts
Flame Resistant Safety Vests | Flame Resistant T Shirts | Flame Resistant Rain Gear

Flame resistant clothing is not to be confused with flame "retardant" or "fire retardant" clothing. fire retardant is a term used for curtains, pajamas and bedding, not protective clothing. A fire retardant fabric is surface treated and this treatment can be washed out rendering the FR properties useless. Flame "resistant" is the proper term for protective clothing used for the workplace where fire hazards may exist.