Health & Environmental Research Online (HERO)


Print Feedback Export to File
1271789 
Journal Article 
Ignition of Methane-Air Mixture by Frictional Sparks from Light Alloys 
Komai, T; Uchida, S; Umezu, M 
1994 
1 
Safety Science
ISSN: 0925-7535 
Elsevier 
NIOSH/00218762 
17 
2 
91-102 
A drop weight type testing apparatus was used in a laboratory scale experiment to study the incendivity of some typical light alloys. Frictional sparks were created by the free fall of a test sample on to a rusted steel plate. Four kinds of light alloy containing mainly aluminum and/or magnesium plus a special sample to which a small amount of beryllium was added were tested. The findings indicated that frictional sparks between light alloys and steel have a high probability of igniting mixtures of air and methane due to the hot surface induced by the thermite reaction. The height of the sample was shown to be one of the important factors in deciding the incendivity under free fall. The incendivity of light alloys can be estimated by using the impact energy required to obtain 50% of the probability of ignition as an index. A close correlation was noted between the incendivity and the content of magnesium for three kinds of light alloys. When a small quantity of beryllium was added to the magnesium base light alloys, the incendivity of light alloys became lower. However, this did not decrease the ignitability as was observed for the aluminum-silicon type light alloy. 
DCN-218438; Flammable gases; Fire hazards; Fire prevention; Ignition sources; Mechanical properties; Explosive hazards; Mining industry; Confined spaces