(2) Hose--four specimens each 6 inches long by 1/2-inch
wide by thickness of the hose.
(b)Flame-test apparatus. The principal parts of the
apparatus within and/or appended to a 21-inch cubical test gallery are:
(1) A support stand with a ring clamp and wire gauze.
(2) A Pittsburgh-Universal Bunsen-type burner (inside
diameter of burner tube 11 mm.), or equivalent, mounted in a burner placement
guide in such a manner that the burner may be placed beneath the test
specimen, or pulled away from it by an external knob on the front panel of
the test gallery.
(3) A variable-speed electric fan and an ASME flow nozzle
(16-8 1/2 inches reduction) to attain constant air velocities at any speed
between 50-500 feet a minute.
(4) An electric timer or stopwatch to measure the duration
of the tests.
(5) A mirror mounted inside the test gallery to permit a
rear view of the test specimen through the viewing door.
(c)Mounting of test specimen. The specimen shall be clamped
in a support with its free end centered 1 inch above the burner top. The
longitudinal axis shall be horizontal and the transverse axis inclined at 45°
to the horizontal. Under the test specimen shall be clamped a piece of
20-mesh iron-wire gauze, 5 inches square, in a horizontal position
1/4-inch below the pulley cover edge of the specimen and with about
1/2-inch of the specimen extending beyond the edge of the gauze.
(d)Procedure for flame tests. (1) The Bunsen burner,
retracted from the test position, shall be adjusted to give a blue flame 3
inches in height with natural gas.
(2) The observation door of the gallery shall be closed
for the entire test.
(3) The burner flame shall be applied to the free end of
the specimen for 1 minute in still air.
(4) At the end of 1 minute the burner flame shall be
removed, the ventilating fan turned on to give an air current having a
velocity of 300 feet per minute, and the duration of flame measured.
(5) After the test specimen ceases to flame, it shall
remain in the air current for at least 3 minutes to determine the presence
and duration of afterglow. If a glowing specimen exhibits flame within 3
minutes the duration of flame shall be added to the duration of flame
obtained according to paragraph (d)(4) of this section.
(e)Test requirements. The tests of the four specimens cut
from any sample shall not result in either duration of flame exceeding an
average of 1 minute after removal of the applied flame or afterglow exceeding
an average of 3 minutes duration.
(2) Hose--hose conduit accepted by MSHA as flame-resistant
shall be marked as follows: Impressed letters, raised letters on depressed
background, or printed letters with the words "Flame-Resistant, USMSHA No.
------" at intervals not exceeding 3 feet. This number will be assigned to
the manufacturer after the sample has passed the tests. The letters and
numbers shall be at least 1/4-inch high.