This safety alert is issued following the occurrence of an aluminum dust explosion occurred at a motorcycle rim manufactured factory in the early November 2010.
8 workers were injured as a result of the dust explosion and 2 of them received serious injuries. The explosion also caused damage to buildings and manufacturing plant, the destruction of the dust collector system and also broke windows of factories nearby.
From investigations carried out, an explosion occurs due to a small fire that originated from the polishing machine and then caused a chain of dust explosion occurred.
Combustion and Dust Explosion
As well as to all theories of combustion, combustion occurs when fuel dust (ie, combustible dust) is exposed to heat (such as the ignition source) in the presence of oxygen. But, to cause the production of combustible dust explosion is, it requires the presence of simultaneous (simultaneous) two other elements which are the particulate matter and the limited space (confinement) as shown in the Dust Explosion Pentagon.
Suspended dust would easily burn very fast and limited space (confinement) will cause the production of a very high pressure within the shortest time. If the absence of dust elements either suspended or limited space (confinement), it will avoid an explosion BUT fire still can occur.
Control Measures to prevent dust explosions:
To prevent dust explosions, the following control measures shall be as follows:
- Control of Dust – well-kept work place and the plant should be properly well-maintained and appropriate installation of Local Exhaust Ventilation and meet the international engineering standards.
- Control of ignition sources - sources of ignition such an electrostatic current release, friction, chemical reactions, hot surfaces and hot work in the workplace should be identified and prevented from working in the area affected by the combustible dust.
- Dust explosion damage control - like installing the explosion relief openings on the machine and LEV.
Other Information and Guides that can be referred:
- Dust Explosions in Factories, Precautions Required With Combustible Dusts, Department Of Labour, 1985, New Zealand.
- A Comprehensive Guideline to Industrial Explosion Protection Including Scientific Basics, Case Studies about Incidents, Prevention Methods and Constructive Protection Measures, REMBE’s Booklet Of safety And Security (BOSS)
- U.S. Chemical Safety and Hazard Investigation Board, Combustible Dust Hazard Study.