FR Dictionary

Key Terms in Flame-Resistant Clothing

Understanding the Hazards and Standards

The first step in adequately protecting your workforce is understanding the hazards and standards that apply to your industry, as well as the products available to address them. Workrite Uniform Company’s helpful FR Dictionary covers the flame-resistant (FR) clothing terms and acronyms you’ll need to know in order to make informed decisions and protect your workforce.

General Terms

  • Flame Resistant (FR) – A fabric or product that resists ignition and self extinguishes after removal of the ignition source
  • Flame Retardant – A chemical treatment applied to a flammable base fabric that gives it FR properties
  • Inherent – An FR fabric that is made of fibers that are flame resistant due to the chemical structure of the fibers and has not been chemically treated
  • Treated – An FR fabric in which flame-retardant chemicals are added to the fabric after it has been woven or knitted
  • Vertical Flame Test – A basic test that determines whether or not a fabric is FR by measuring how much of the fabric is consumed after 12 seconds of flame exposure
  • Char Length – A measurement of the damaged fabric after the Vertical Flame test

Fabric Terms

  • Aramid – The chemical family of FR fibers like Nomex® (meta-aramid) and Kevlar (para-aramid)
  • Nomex – The brand name for the meta-aramid produced by DuPont™
  • Kevlar – The brand name for the para-aramid produced by DuPont
  • Modacrylic – A generic name for a type of inherently FR fiber (e.g., the fiber used in Protera® and Tecasafe® plus)
  • Lyocell – A cellulose fiber made from dissolving wood pulp (a type of rayon)
  • PBI – Short for the polymer Polybenzimidizole; an inherently FR fiber made by Celanese Inc.
  • FRC – Flame-resistant clothing

Standards and Organizations

  • OSHA – The Occupational Safety and Health Administration
  • NFPA – The National Fire Protection Association
  • ASTM International –The American Society for Testing and Materials
  • NESC – The National Electrical Safety Code (safety standards for electric utilities)
  • ANSI – American National Standards Institute
  • CSA – Canadian Standards Association
  • CGSB – Canadian General Standards Board
  • NFPA 70E – The Standard for Electrical Safety in the Workplace
  • NFPA 2112 – The Standard on Flame-Resistant Garments for Protection of Industrial Personnel Against Flash Fire
  • ANSI 107 – The Standard for High Visibility Safety Apparel
  • CSA Z462 – Workplace Electrical Safety (Canadian equivalent of NFPA 70E)
  • CGSB 155.20 – Workwear for Protection Against Hydrocarbon Flash Fire (Canadian equivalent of NFPA 2112)
  • CSA Z96 – High Visibility Safety Standard (Canadian equivalent of ANSI 107)

Electrical Hazard Terms

  • Arc Rating – Value describing a fabric’s performance under exposure to an electrical arc discharge based on testing that determines when the amount of exposure results in a 50-percent probability of causing the onset of second-degree skin burns; expressed in cal/cm² as either an ATPV or an EBT
  • ATPV – Arc Thermal Performance Value of a fabric shown in cal/cm²
  • EBT – Energy of Breakopen Threshold; the cal/cm² at which the fabric breaks open before it reaches its ATPV
  • HRC – Hazard Risk Category; a term used specifically in NFPA 70E; each specific task listed in the 70E table establishes one of five HRC category requirements for the protective clothing and PPE to be worn while performing that task, and each category outlines the minimum arc rating (cal/cm²) for the FR clothing and other PPE required

Flash Fire Terms

  • TPP – Thermal Protective Performance of a fabric; the amount of heat it takes to pass through the fabric and cause a second-degree burn; CGSB 155.20 requires a fabric have a minimum of 6 cal/cm² when tested with a spacer
  • Manikin Test/Body Burn – A simulated flash fire test using an instrumented manikin to calculate the estimated percentage of second and third degree body burns after three seconds of exposure; NFPA 2112 requires the percentage to be below 50 percent
  • HTP – Heat Transfer Performance of a fabric; the amount of heat it takes to pass through a fabric to cause second-degree burns based on the skin burn curve; NFPA 2112 requires a fabric to have a minimum of 6 cal/cm² when tested with a spacer and 3 cal/cm² in contact

ISO 9001:2008 Certified

As an ISO 9001:2008-certified company, participant in numerous industry associations and standards-writing organizations, and owner of numerous trusted brands, Workrite Uniform’s expertise is backed by a steadfast commitment to superior protection and quality.