- The oldest test used to identify the fibres is burning test.
- It consist of following observations:
(a) Odour
of the gaseous products of combustion (smoke)
(b) Rate
and character of burning
(c) Action
after removal of flame
(d) Character
of ash
Equipment:- source of flame
ð The best sources are a Bunsen burner or an alcohol lamp.
ð Cigarette lighter can also be used as a source.
ð Match is a poorest source, as its burning odour.
Manipulation:-
ð Fibre should be heavy yarn; length should be 1.5 to 2” by twisting.
ð Twist of the fibre should be tight, so burning rate will be slow.
ð The fibre sample should be slowly introduced to the flame from the side.
ð If the fibre burns in the flame, remove it and note whether it continue to burn. (if it burns without contact with the flame is said to support combustion)
ð If the fibre fails to support the combustion, quickly note the odour of the gaseous products of combustion.
ð Do not move the fibre any more than is absolutely necessary as this will cause the smoke to be dispersed in the air.
ð Note also whether the fibre continues to glow after the flame has been extinguished.
ð Finally examine the ash from the standpoint of amount from colour and hardness.
ð Table shows the burning characteristics of the fibre under the conditions stated above.
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