QUICK FACTS

All manufactured garments are required to meet U.S. flammability standards. The standard 16 CFR Part 1610 measures ease of ignition and flame spread time. All non-FR fabrics fit into one of three classes.

Class 1: NormaI flammability
Class 2: Intermediate flammability
Class 3: Rapid/Intense burning
All wearing apparel sold in the U.S. must
meet Class 1 or Class 2 category requirements.

Flame resistan Untreated 100% cotton fabrics are not flame resistant.

Common causes of ignition of work apparel:

  • Flammable liquids
  • Flammable soils
  • Molten metals
  • Sparks
  • Slag from flame cutting
  • Welding
  • Open flames
  • High energy electrical discharges
  • Electric arc events
  • Vapors from volatile liquids
  • Combustible dusts

    		•

    Inherently Flame Resistant Fibers
    Flame resistance is an essential characteristic of the fiber.

    		 Treated Fabrics
    Flame resistance is achieved through special treatments applied to the fiber or fabric.
    Flame Resistant
    The characteristic of a fabric to resist ignition and to self extinguish if ignited.

    Flame Retardant
    A chemical substance used to provide flame resistance.

    Primary Protective Clothing
    For activities where significant exposure to flame is likely.

    		 Secondary Protective Clothing
    For continuous wear in designated areas where intermittent exposure to flaame is possible.

    Chemical Resistance
    Relates to the ability of fabrics to withstand exposure to various chemicals.

    Stoll Curve
    Developed by Alice Stoll in the 1960’s, and used in many tests to predict the thermal protective performance of textile materials for FR apparel.
    Some flame retardant finishes for 100% cotton and cotton blend fabrics are durable for the life of the garment.

    Blending
    Using two or more fibers in one fabric to balance fiber strengths and weaknesses.

    		 FR Fabric Selection Considerations
    Thermal Protection Static Resistance
    Comfort Durability
    Stability Appearance
    Relative Cost Available Colors
    Ease of Laundry Maintenance
    The Flame Resistance of Cloth: Vertical test records:
    AFTERFLAME
    The number of seconds there is a visible flame on the fabric.

    AFTERGLOW
    The number of seconds there is a visible glow on the fabric.

    CHAR LENGTH
    The length of fabric destroyed by flame. 5903.1 establishes a test method only with no pass/fail requirements.


    		 Workers Exposed to Electric Arcs ASTM F 1506 Requires
  • Thread, findings and closures do not contribute to the wearer’s injuries in an electric arc exposure.
  • Knit or woven fabrics may not melt and drip, or have more than 2.0 seconds afterflame or 6.0 inches char length.
  • Fabrics can not have more than 5.0 seconds afterflame in an electric arc exposure test.
  • Arc rating must appear on garment labels.
    • ASTM F 1958
    1. Determines probability of ignition at a range of arc exposures.
    2. Used to test FR and non-FR materials.
    3. Fabrics are tested as shirts mounted on mannequins.

    ASTM F 1959-99

    1. Determines ATPV of materials based on electric arc exposure.
    2. Fabrics are mounted on flat panels.
    3. E BT determined if ATPV cannot be calculated because of breakopen.

    ASTM F 1891

    • Fabric must withstand 30 PSIG water pressure without leaking.
    • Seam hydrostatic resistance 3 psi/ 2 minutes.
    • No melt or drip or more than 2.0 seconds Afterflame or 6.0 inches Char Length in flame resistance testing.
    • The ATPV, E BT, and/or E BTAS must be equal to or greater than 5.0 cal/cm 2.
    • Breakopen Threshold Energy Above Stoll (EBTAS) determined from the five highest energy values that did not cause breakopen.

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