30 CFR § 7.26
Flame test apparatus.
The principal parts of the apparatus used to test for flame-resistance of
brattice cloth and ventilation tubing shall be constructed as follows:
(a) A 16-gauge stainless steel gallery lined on the top, bottom and
both sides with 1/2 inch thick Marinite or equivalent insulating material
yielding inside dimensions approximately 58 inches long, 41 inches high, and
30 inches wide;
(b) Two 3/8-inch diameter steel J hooks and a 9/16-inch diameter
steel rod to support the sample located approximately 2 3/16-inches from the
front and back ends of the test gallery, 1 1/2-inches from the ceiling
insulation and centrally located in the gallery along its length. Samples
shall be suspended to preclude folds or wrinkles;
(c) A tapered 16-gauge stainless steel duct section tapering from a
cross sectional area measuring 2 feet 7 inches wide by 3 feet 6 inches high
at the test gallery to a cross-sectional area 1 foot 6 inches square over a
length of 3 feet. The tapered duct section must be tightly connected to the
test gallery;
(d) A 16-gauge stainless steel fan housing, consisting of a 1 foot 6
inches square section 6 inches long followed by a 10 inch long section which
tapers from 1 foot 16 inches square to 12 inches diameter round and
concluding with a 12 inch diameter round collar 3 inches long. A variable
speed fan capable of producing an air velocity of 125 ft./min. in the test
gallery must be secured in the fan housing. The fan housing must be tightly
connected to the tapered duct section;
(e) A methane-fueled impinged jet burner igniting source, measuring
12 inches long from the threaded ends of the first and last jets and 4 inches
wide with 12 impinged jets, approximately 1 3/8-inches long and spaced
alternately along the length of the burner tube. The burner jets must be
canted so that they point toward each other in pairs and the flame from these
pairs impinge upon each other.