This standard specifies the minimum performance requirements and test methods for flame-resistant fabric and components and the design and certification requirements for garments for use in areas at risk from flash fires. Flame resistant fabrics must pass a comprehensive list of thermal tests, including the following:
- ASTM F2700 – Heat Transfer Performance (HTP) test – This test is a measure of the unsteady state heat transfer properties of garment materials.
- ASTM D6413 – Vertical Flammability (Flame Resistance) Test – This test is used to determine how easily fabrics ignite and continue to burn once ignited.
- Thermal Shrinkage Resistance Test – This test measures a fabric’s resistance to shrinkage when exposed to heat.
- Heat Resistance Test – This test measures how fabrics and components react to the high heat that could occur during a flash fire.
- ASTM F1930-11 – Thermal Manikin Test – This test provides an overall evaluation of how the fabric performs in a standardized coverall design after three-second thermal exposure.
- FTMS 191A – Thread Melting Resistance Test – Thread used in flame resistant garments must withstand temperatures of up to 500 degrees F.
This standard addresses electrical safety-related work practices for employee workplaces and requires employees working on or near energized parts and equipment to wear flame-resistant clothing that meets the requirements of ASTM F1506.
The NFPA-70E standard gives guidance for selecting the appropriate PPE according to the level of risk involved in a particular job. Risk areas are categorized by the expected level of incident energy in the event of an electric arc. According to the table, there are four categories, ARC 1 (which is low risk), through 4 (which is high risk and requires FR clothing with a minimum ARC rating of 40cal/cm2). The higher the ARC rating value, the greater the protection.
This performance specification covers the flame resistance of textile materials to be used for wearing apparel for use by electrical works exposed to momentary electric arc and related hazards.
These textile materials must meet the following performance requirements:
- A general requirement that thread and components used in garment construction shall not contribute to the severity of injuries to the wearer in the event of a momentary electric arc and related thermal exposure.
- A set of minimum performance specifications for knit and woven fabrics including strength, colorfastness, flame resistance before and after washing and arc test results.
- Testing for flame resistance in accordance with ASTM test method D6413 vertical flame test.
- When tested as received in accordance with ASTM test method F1959 arc performance, the fabric may not have more than 5.0 seconds after flame time when tested.
- Garments must be labeled with the following:
- Tracking code.
- Statement that the garments meet the requirements of F1506.
- Manufacturer’s name, size, information.
- Care instructions and fiber content.
- ARC rating (ATPV) or (EBT).
Standard Test Method for Determining the ARC Rating of Materials for Clothing
FABRIC ONLY TEST.
Laundering of FR Fabrics
The Flame Resistant finish is retained for the normal life cycle of the garment provided that the care instructions are adhered to.
Pretreatment: If stains are difficult to remove, they can be treated before putting into the washing machine with a liquid detergent applied directly to stains and lightly rubbed. Heavier and stubborn stains should be pretreated with a commercial stain removal product at the earliest opportunity and sufficient time allowed for the pretreatment to penetrate and loosen the stain. Never use chlorine bleach or washing detergents containing bleach as these will reduce the flame resistance properties of the fabric. Fabric softeners, starches, and other laundry additives are not recommended as they can mask the flame resistance performance and may also act as a fuel in case of combustion.
Always wash contaminated workwear separately, do not mix with non-workwear. Flame Resistant fabric can usually be washed at high temperatures however it is the components (i.e. the reflective tape, badging, etc.) on a finished garment that dictates the maximum washing temperature that the garment can be washed at. Always follow the washing temperature on the garment label. Always wash and dry garments inside out to minimize surface abrasion and help maintain the surface appearance of the fabric. Zippers should be closed during washing.
To ensure a more efficient, cleaner wash, avoid overloading the machine so the garments can move freely through the wash and rinse cycles.
Tumble drying is not usually recommended as the temperature used is often too high and can cause garment shrinkage. It is vital that cotton or cotton mix garments are not over dried. Overdrying is the main cause of excessive garment shrinkage. Do not hang in direct sunlight. This can cause fading.