30 CFR § 7.406
Flame test apparatus.
The principal parts of the apparatus used to test for flame resistance of
electric cables, signaling cables and splices shall include:
(a) Test chamber. A rectangular enclosure measuring 17 inches
deep by 14 inches high by 39 inches wide and completely open at the top and
front. The floor or base of the chamber shall be fabricated or lined with a
noncombustible material that will not extinguish burning matter which may
fall from the test specimen during testing. The chamber shall have permanent
connections mounted to the back wall, sides, or floor of the chamber which
extend to the sample end location. These are used to energize the electric
cable and splice specimens. They are not used, but may stay in place, when
testing signaling cables.
(b) Specimen holder (support). A specimen holder (support)
consisting of three separate metal rods each measuring approximately 3/16 inch
in diameter (nominal) to support the specimen. The horizontal portion of the
rod which contacts the test specimen shall be approximately 12 inches in
length.
(c) Gas ignition source. A standard natural gas type Tirrill
burner, with a nominal inside diameter of 3/8 inch, to apply the flame to the
test specimen. The fuel for the burner shall be natural gas composed of at
least 96 percent combustible hydrocarbons, with at least 80 percent being
methane.
(d) Current source. (For electric cables and splices only). A
source of electric current (either alternating current or direct current) for
heating the power conductors of the test specimen. The current source shall
have a means to regulate current flow through the test specimen and have an
open circuit voltage not exceeding the voltage rating of the test
specimen.
(e) Current measuring device. (For electric cables and
splices only). An instrument to monitor the effective value of heating
current flow through the power conductors of the specimen within an accuracy
of ±1 percent.
(f) Temperature measuring device. (For electric cables and
splices only). An instrument to measure conductor temperature within an
accuracy of ±2 Percent without the necessity of removing material from the
test specimen in order to measure the temperature.
[57 FR 61221, Dec. 23, 1992]
