PROCEDURE: 5.1 Cut 5 specimens each measuring 2 x 6 in. (Samples may be cut from east
to west or north to south or whichever orientation would present the most serious method
of flammability.)
5.2 For plain surface fabrics, the long dimension shall be that in which they burn most
rapidly.
5.3 For fabrics with raised-fiber surfaces, the direction of the lay of the surface
fibers shall be parallel with the long dimension of the specimens. For textiles with
varying depths of pile, tufting, etc., the specimens are taken from that part and test on
that surface which has the fastest rate of burning.
5.4 If the specimens do not ignite or are very slow burning in the preliminary test or
should have a flame retardant finish, a sample is subjected to the dry cleaning and
washing procedures. Specimens are taken from the refurbished swatches.
5.5 Specimen dimensions are marked on the backside and in the direction in which the
fabric burns most rapidly by a staple affixed to it.
5.6 Fabrics with raised fiber surfaces must be brushed. Put specimen in place on the
brushing device carriage, raise the brush, push the carriage to the rear, lower the brush
to the face of the specimen. Draw the carrier forward once against the lay of the
raised-fiber surface. Plain surface fabrics do not require this treatment.
5.7 Clamp specimens individually in the specimen holders.
5.8 Dry specimens mounted in holders in a horizontal position in an oven for 30 minutes
at 221° F/105° C.
5.9 Place specimens over anhydrous calcium chloride in a desiccator until cool, but not
for less than 15 minutes.
5.10. Adjust flammability tester rack so that the finger just touches an unofficial
specimen. This step is to insure that the tip of the burner is exactly 5/16 in. from the
fabric when test is conducted.
5.11. Adjust flame length to exactly 5/8" long.
5.12. Remove mounted specimen from desiccator and place it in position on the rack in
the chamber.
5.13. Place stop cord and weight in proper position to test.
5.14 Push button to run test. The flame is automatically brought into ignition position
and held for exactly 1.0 seconds before it retracts back in to the ready position. The
time starts at the time the button is pushed. The timer turns itself off when the stop
cord burns and the weight drops.
EVALUATION AND REPORTING: 6.1 Record the time of flame spread and type of burning
observed for each specimen.
6.2 Time of flame spread is the average for the 5 specimens.
6.3 Base Fabric Ignition or Fusing - for fabrics with raised fiber surfaces, report
this fact when more than 1 of 5 specimens perform this way or when more than 2 of 10.
6.4 Report results shall be the flammability before or after dry cleaning/washing,
whichever is lower. Classify the fabric per 1610.3 (smooth or napped).
6.5 Classify into one of the following flammability classes:
a. Class 1, Normal Flammability - textiles which have no unusual burning
characteristics.
b. Class 2, Intermediate Flammability - textiles having flammability characteristics
between normal and rapid and intense burning.
c. Class 3, Rapid and Intense Burning - textiles considered dangerously flammable and
unsuitable for clothing due to rapid and intense burning.
6.6 Based on the time of flame spread, it is classified into one of the following 3
classes of Flammability:
a. Smooth fabric - the time of flame spread should be 3.5 seconds or more to classify
as Class 1.
b. Smooth fabric - the time of flame spread is less than 3.5 seconds, then classify as
Class 3.
c. Raised-fiber fabric - the time of flame spread should be 7.0 seconds or more to
classify as Class 1.
d. Raised-fiber - if the raised fiber flashes on the base fabric but does not ignite, char
or fuse, then classify as Class 1.
e. Raised-fiber fabric - if the flame spread id more than 4 seconds but not more than
seconds, classify as Class 2.
f. Raised-fiber fabric - if the flame spread is less than 4 seconds and fabric ignites,
chars, or fuses the base fabric, then classify as Class 3.
