(a) Base burn (also known as base fabric ignition or fusing) means the point at which the flame burns the ground (base) fabric of a raised surface textile fabric and provides a self-sustaining flame. Base burns, used to establish a Class 3 fabric, are those burns resulting from surface flash that occur on specimens in places other than the point of impingement when the warp and fill yarns of a raised surface textile fabric undergo combustion. Base burns can be identified by an opacity change, scorching on the reverse side of the fabric, or when a physical hole is evident.

(b) Burn time means the time elapsed from ignition until the stop thread is severed as measured by the timing mechanism of the test apparatus.

(c) Dry cleaning means the cleaning of samples in a commercial dry cleaning machine under the conditions described in § 1610.6.

(d) Film means any non-rigid, unsupported plastic, rubber or other synthetic or natural film or sheeting, subject to the Act, or any combination thereof, including transparent, translucent, and opaque material, whether plain, embossed, molded, or otherwise surface treated, which is in a form or state ready for use in wearing apparel, and shall include film or sheeting of any thickness.

(e) Flammability means those characteristics of a material that pertain to its relative ease of ignition and relative ability to sustain combustion.

(f) Flame application time means the 1 second during which the ignition flame is applied to the test specimen.

(g) Ignition means that there is a self-sustaining flame on the specimen after the test flame is removed.

(h) Interlining means any textile which is intended for incorporation into an article of wearing apparel as a layer between an outer shell and an inner lining.

(i) Laundering means washing with an aqueous detergent solution and includes rinsing, extraction and tumble drying as described in § 1610.6.

(j) Long dimension means the 150 mm (6 in) length of test specimen.

(k) Plain surface textile fabric means any textile fabric which does not have an intentionally raised fiber or yarn surface such as a pile, nap, or tuft, but shall include those fabrics that have fancy woven, knitted or flock-printed surfaces.

(l) Raised surface textile fabric means any textile fabric with an intentionally raised fiber or yarn surface, such as a pile, including flocked pile, nap, or tufting.

(m) Refurbishing means dry cleaning and laundering in accordance with § 1610.6.

(n) Sample means a portion of a lot of material which is taken for testing or for record keeping purposes.

(o) Specimen means a 50 mm by 150 mm (2 in by 6 in) section of sample.

(p) Stop thread supply means No. 50, white, mercerized, 100% cotton sewing thread.

(q) Surface flash means a rapid burning of the pile fibers and yarns on a raised fiber surface textile that may or may not result in base burning.

(r) Textile fabric means any coated or uncoated material subject to the Act, except film and fabrics having a nitro-cellulose fiber, finish, or coating, which is woven, knitted, felted or otherwise produced from any natural or manmade fiber, or substitute therefore, or combination thereof, of 50 mm (2 in) or more in width, and which is in a form or state ready for use in wearing apparel, including fabrics which have undergone further processing, such as dyeing and finishing, in garment form, for consumer use.