This performance specification covers the design characteristics and associated test methods that relate specifically to the flame resistance of textile materials used in the fabrication of basic protection level occupational apparel worn by electrical workers who are exposed to momentary electric arc and related thermal hazards such as exposure to open flame and radiant heat. When evaluated in accordance with the test procedures enlisted herein, knit fabrics and woven fabrics of different fabric weights shall conform to individually specified values of the following properties: colorfastness such as laundering shade change, dry-cleaning shade change, and dimensional change; initial flammability characteristics and flammability characteristics after 25 washes/dry-cleaning such as char length and afterflame time; and arc test rating. Knit fabrics shall additionally be tested and adhere accordingly to bursting strength characteristics. Conversely, woven fabrics shall also be tested and adhere accordingly to breaking load, tear resistance, and seam slippage characteristics.

1.1 This performance specification covers the flame resistance of textile materials to be used for wearing apparel for use by electrical workers exposed to momentary electric arc and related thermal hazards.

Note 1—This performance specification does not cover coated fabrics commonly used in rainwear.

Note 2—At present, a bench scale arc test for laboratory use is not available. It is the intent of the committee to continue the search for an acceptable laboratory test based on either an electric arc exposure or an acceptable alternative, which will form the basis of a modification of this performance specification.

1.2 Materials used for basic protection levels are covered.

1.3 Protective properties relate to thermal exposure from momentary arc and associated exposure to open flame and radiant heat. (See Appendix X1.)

1.4 This performance specification covers wearing apparel design characteristics that relate specifically to protection from exposure to momentary electric arc and that relate to the utility of the wearing apparel.

Note 3—A number of other thermal test methods are under consideration and development and, when evaluated and proved effective by Committee F18, will be incorporated in either this performance specification or an appropriate alternative test method or specification.

1.5 This standard should be used to evaluate and describe the properties of materials, products, or assemblies in response to heat and flame under controlled laboratory conditions. It should not be used to describe or appraise the fire hazard or fire risk of materials, products, or assemblies under actual fire conditions.

1.5.1 The results of this evaluation may be used as elements of a fire-risk assessment that takes into account all of the factors that are pertinent to an assessment of the fire hazard of a particular end use.

1.6 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.7 The following precautionary caveat pertains only to the test methods portion, Section 7, of this performance specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.