[Code of Federal Regulations]
[Title 30, Volume 1]
[Revised as of July 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 30CFR7.28]

[Page 18-19]
 
                       TITLE 30--MINERAL RESOURCES
 
  CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR
 
PART 7--TESTING BY APPLICANT OR THIRD PARTY--Table of Contents
 
            Subpart B--Brattice Cloth and Ventilation Tubing
 
Sec. 7.28  Test for flame resistance of rigid ventilation tubing.

    (a) Test procedures. (1) Prepare 6 samples of ventilation tubing 48 
inches in length with all flared or thickened ends removed. Any sample 
with a cross-sectional dimension greater than 24 inches must be tested 
in a 24-inch size.
    (2) For each test, suspend the sample in the center of the gallery 
by running a wire through the 48-inch length of tubing.
    (3) Use a front exhaust system to remove smoke escaping from the 
gallery. The exhaust system must remain on during all testing but not 
affect the air flow in the gallery.
    (4) Set the methane-fueled impinged jet burner to yield a flame 
height of 12 inches as measured at the outermost tip of the flame.
    (5) Apply the burner to the front lower edge of the tubing so that 
two-thirds of the burner is under the tubing and the remaining third is 
exposed to allow the flames to curl onto the inside of the tubing. Keep 
the burner in contact with the material for 60 seconds. If melting 
material might clog the burner orifices, rotate the burner slightly 
during application of the flame.
    (6) Test 3 samples in still air and 3 samples with an average of 125 
ft./min. of air flowing past the sample.
    (7) Record the propagation length and duration of burning for each 
of the 6 samples. The duration of burn is the total burning time of the 
specimen during the flame test. This includes the burning time of any 
material that falls on the floor of the test gallery during the igniting 
period. However, the suspended specimen is considered burning only after 
the burner is removed. Should the burning time of a suspended specimen 
and a specimen on the floor coincide, count the coinciding burn time 
only once.
    (8) Calculate the average duration of burning for the first 3 
samples (still air) and the second 3 samples (125 ft./min. air flow).

[[Page 19]]

    (b) Acceptable performance. The ventilation tubing shall meet each 
of the following criteria:
    (1) Flame propagation of less than 4 feet in each of the 6 tests.
    (2) An average duration of burning of less than 1 minute in both 
groups of 3 tests.
    (3) A duration of burning not exceeding 2 minutes in each of the 6 
tests.

[53 FR 23500, June 22, 1988, as amended at 60 FR 33723, June 29, 1995]