A P P A R E L Q U A L I T Y

M A N A G E M E N T

F L A M M A B I L I T Y
CONTENTS

What is flammability?

Some definations related to

flammability

Factors affecting flame resistance

Test Methods

Recent Progress

Finishing
 WHAT IS
FLAMMABILITY ?
Flammability is defined as how easily a fiber or
fabric will burn or ignite, resulting in fire or
combustion. It is the ease with which a material
is ignited, the intensity with which it burns and
releases heat once ignited, its propensity to
spread fire, and the rate at which it generates
smoke and toxic combustion products during
gasification and burning. A comprehensive
evaluation of a material's overall flammability
may require data from several laboratory tests,
perhaps combined with some form of analysis
or modeling to interpret the results properly.
Several of the fire properties like ignitability
can be determined from bench-scale
flammability tests.
 SOME

DEFINATIONS

AND TERMS

RELATED TO

FLAMMABILITY
Flammable: Flameproof: Flame resistance


& rating:
A flammable A flame proof
The time in seconds

fabric is one fabric is one which The time in seconds

necessary for
which doesn’t necessary of for
the propagation
propagates propagate flame, the propagation of flame in a

flame in a vertical strip

flame, i.e. it i.e. any flame goes vertical strip of 100 inch
of 100 inch. A flame
continues to out quickly when
resistant fabric is one
burn after the the
whose flame resistance
igniting flame igniting flame is
rating is high, i.e. above
has been with-drawn.
150.
removed.
Inherently flame Durably flame- Temporarily
proof material: proof material: flameproof

has not
material:
A material that The ability of a

Material which

been subjected to any

flameproof
complies

flameproof
material to retain its

with the
processing's yet it has
flame proof quality
requirements of

the flame-proofing
even after being Clause 3 of B.S. 3120,

ability. submitted to
before, but
washing treatments. not after, the

prescribed washing

treatment.
 Factors affecting flame
resistance
1. Fibre Content
2. Burning Process
3. Fabric weight and structure
4. Finishes
5. Flammability Regulations
1. FIBRE CONTENT

Fiber content is probably the most important fabric property that

affects flammability . Cellulosic fabrics, such as cotton and rayon,
without a flame-resistant finish, can burn easily. In contrast, wool
fabrics, especially heavy weight, usually self extinguish because
of their high ignition temperatures (570ºC~600ºC) and high
moisture content. Thermoplastic fibers, such as nylon, polyester,
and olefin, do not ignite easily because they shrink away when
exposed to flame. However, if they are forced to ignite or are
engulfed in flames, thermoplastic fabrics will melt and burn.
Blends of fibers, or yarns of different fibers, are more likely to be
flammable than fabrics made from a single fiber type .
 2. BURNING PROCESS

In the burning process, cotton in the blend

acts as a support or scaffold to support the
burning polyester fiber, which prevents the
melting polyester from dripping away as pure
polyester products do, and allows the melting
polyester to continue to contribute to the
burning system. Similar concerns may apply to
products made of fabrics and fillings, such as
upholstered seating, mattresses, bed covers,
duvets and pillows. If the fabrics and fillings
are highly flammable, their combinations can
be even more dangerous.
3. FABRIC WEIGHT AND STRUCTURE

Heavier fabrics ignite less easily and burn more

slowly than lighter weight fabrics .
A tightly woven and knitted fabric also ignites
more difficultly and burns lower than sheer
fabrics. The reason is because there is more air
space and more oxygen among fibers in the
sheer fabrics to fuel the flames as the fabrics
burn. . The lightweight fabrics burned faster
than the heavier ones no matter what the fabric
type was. As the fabric weight increased, flame
temperature increased, indicating that heavy
fabrics provided more amount of fuel sustaining
burning.
 4. FINISHES

Flame-retardant (FR) finishes were developed

for flammable fabrics to provide flame resistant
properties and to change the burning behavior
of the fabric. FR finishes can be used on cotton,
rayon, nylon and polyester fabrics .
By chemically modifying the surface of the
fibers, FR finishes make the fabric less
flammable by reducing the volume of
flammable gases that generate heat further
decomposing the fiber. Phosphorus containing
substances, which react chemically with the
fibers, are the most common FR finishes for
cellulosic materials
 5. FLAMMABILITY REGULATIONS

In the late 1940s, a number of people were seriously injured

due to burning apparel; the most dangerously flammable
fabrics were brushed rayon. In reaction to highly flammable
garments resulting in many cases of injury or death, the
Flammable Fabrics Act (FFA), a federal law, was passed by
Congress in 1953. Under this regulation, the use and sale of
highly flammable textile materials was prohibited. Local and
state laws and other regulations imposed more restrictions
on the use of flammable textile materials in public buildings
 Measurement Of
Fabric

There are two common tests

for the flammability of
clothing textiles. They are the
45-Degree Test
Vertical Flammability Test
45-DEGREE TEST
The 45-Degree Test is used in 16 CFR 1610, Standard for the
Flammability of Clothing Textiles, which is a mandatory testing
procedure for all apparel materials. In this test, a specimen of
6" (warp/wale) x 2" (filling/course) is used. Before testing, the
specimens should be dried in an oven and be kept in
desiccators until just prior to testing because the moisture level
in the fabrics would significantly influence the flammability test
result. The specimen is mounted in a holder at a 45° angle and
exposed to flame for one second. After the ignition, the flame is
removed. The time for the specimen to burn up to its entire
length (i.e., 6inches) is recorded. The test is repeated 10 times.
The standard for the flame to spread up the specimen length
should be less than 3.5 seconds for smooth fabrics or 4.0
seconds for napped fabrics.
VERTICAL FLAMMABILITY TEST

The Vertical Flammability Test is applied to children’s

sleepwear, which is required to meet minimal flammability
performance standards of 16 CFR 1615 (size 0-6X) and 16
CFR1616 (size 7-14) after 50 washings and dryings. Similar to
the 45-Degree Test, before testing, the specimens should be
dried in an oven and be kept in desiccators until testing. In the
vertical flammability test, a specimen of 10" (warp/wale) x 3.5"
(filling/course) is suspended vertically in a holder and subjected
to an igniting gas flame along the bottom edge for three
seconds. The char length, which is the amount of fabric burned
or damaged by the flame, is recorded. The test is repeated 10
times. The minimum performance standard of 16 CFR 1615 (size
0-6X) and 16 CFR 1616 (size 7-14)
RECENT PROGRESS IN FLAMMABILITY TEST
METHOD A
Recent tests are modification of vertical strip and 45 degree test , are
found in British Standard .Three test methods are given below:

Method A: Basically, this method is the vertical strip test in which the
rate of propagation of the flame is measured in terms of the distance
in millimetres per minute that the base of flame travels up a strip of
900 mm x 75mm. The time to travel between two markers 500 mm
apart is observed . The rate of propagation is then given by (500/t x
60 mm/min), where t is in seconds.
Some other information's like after-flame, after-glow, char length are
also derived and reported: After-flame: The time in seconds that
elapses between the removal of the std. gas lighting fame and the
flame extinction. After-glow: the time in seconds between flame
extinction and the end of any glowing. The charring: the extent of
charring is given by ‘char length. This is the difference in mm
between the original specimen length and the undamaged length of
the specimen.
METHOD B & C

Method B: Fabrics made from thermoplastic materials don’t

burn in a convenient manner for a satisfactory strip test to
be made. They melt, shrink, curl away from the flame. In
method B the test specimen is hung in the sheet form and
the igniting flame applied at right angles to the sheet and
near to the bottom edge. The amount of damage and time
taken is observed and reported.

Method C: This test is concerned with the transmission of

flame across pile fabrics. To determine the durability of any
flame resistant treatments the following tests are repeated
after washing, drying cleaning or leaching. (The lower speed
of propagation of flame over wool, silk, acetate fabrics is due
to the fact that they melt and drip during burning)
Flame proofing and Flame resistant finishing

Special chemical finishing processes have been developed

which reduce the flammability of the treated fabrics. Some
recent developments have led to the introduction of such
finishes as Proban, Antiflamm, and Lifeguard. Such
finishes
should have following properties:
1) Be permanent and not disappear at the first laundering
or cleaning.
2) Be non-toxic .
3) Be non-irritant to the skin
4) Leave the handle and the other desirable properties
unaffected.
THANKYOU