Dust Explosion In Chemical Processing Plant

Dust explosion followed by fire in chemical processing plant

Dust explosion in a chemical processing plant has resulted in fatality of two workers, whilst two others were seriously injured in the face and body. The plant activity is processing Stearate based chemical for medicines and cosmetics purposes. Investigation found that there are several conditions which could trigger the dust explosion: (1) dusty environment; (2) confined area; (3) presence of oxygen; (4) dispersion of dust and also the (5) existence of ignition.

Some of the safety measures to prevent similar occurrence are:

1. Local Exhaust Ventilation (LEV) system should be installed in appropriate areas that have potential to produce high quantities of dust. This system should be designed in accordance to standards by registered Professional Engineer; constructed and tested periodically in accordance with design specification in order to ensure its effectiveness;
2. As a general guide, the following formula may be used to estimate allowable dust thickness due to housekeeping (Source: NFPA 654)
   
3. Dusting with compressed air or sweeping is not recommended. Use of vacuum cleaner recognized for industrial use and can efficiently carry out work to suck dust which constantly scattered around the processing area;
4. Conduct risk assessment (HIRARC) on dust explosion hazard; management should provide Safe Working Procedures for works and processes which have higher risk in causing fire and dust explosion;
5. Ensure the information, instruction, guidance and training as well as effective supervision given to operators or employees who work in areas which have potential in producing large quantities of dust and;
6. Ensure all machines, electrical fittings are intrinsically safe and comply to standards; and
7. Conduct specific training to all employees about the risk of dust explosion.

References

1. NFPA 654 : Standard for the Prevention of Fire & Dust Explosion in Manufacturing, Processing & Handling of Combustible Particulate Solids (2006)
2. Dust explosion in Factories, Precautions required with combustible dusts, Department of Labour 1985, New Zealand
3. US Chemical Safety and Hazard Investigation Board, Combustible Dust Hazard Study
4. MS IEC 60079-10-2:2010 Explosive Atmospheres-Part10-2: Classification of Area- Combustible Dust Atmospheres
5. MS IEC 60079-10:2003 Electrical Apparatues For Explosive Gas Atmosphere Part 10: Classification of Hazardous Areas
6. Combustible Dust Explosion
7. Combustible Dust Explosion at Motorcycle Rim Manufactured Factory