Dust Explosion Audits & Assessments
Combustible Dust Hazard Evaluation Audits Background
Combustible dusts are fine particles that present an explosion hazard when suspended in air under certain conditions. A dust explosion can be catastrophic and cause employee deaths, injuries, and destruction of entire buildings. In many combustible dust accidents, employers and employees were unaware that a hazard even existed. Between 1980 and 2005, there were 281 documented combustible dust incidents that killed 119 workers, injured 718, and extensively damaged industrial facilities. The incidents occurred in 44 states, in many different industries, and involved a variety of different materials. As a result, in 2007 OSHA embarked on a National Emphasis Program (NEP) to inspect facilities that generate or handle combustible dusts that pose a deflagration or other fire hazard when suspended in air, regardless of particle size or shape. BakerRisk can assist clients with identifying combustible dust explosion hazards, evaluating whether a facility is in compliance with the intent of applicable national codes and standards (e.g., NFPA 654), and developing preventative and mitigation options.
Overview of NFPA 654
NFPA 654: Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids” contains comprehensive guidance on the control of dusts to prevent explosions. The following are some of its recommendations:
- Minimize the escape of dust from process equipment or ventilation systems
- Use dust collection systems and filters
- Utilize surfaces that minimize dust accumulation and facilitate cleaning
- Provide access to all hidden areas to permit inspection
- Inspect for dust residues in open and hidden areas, at regular intervals
- Clean dust residues at regular intervals
- Use cleaning methods that do not generate dust clouds, if ignition sources are present
- Only use vacuum cleaners approved for dust collection
- Locate vents and relief valves away from dust hazard areas
- Develop and implement a hazardous dust inspection, testing, housekeeping, and control program (preferably in writing with established frequency and methods).
Industries Most Susceptible to Dust Explosion Hazards
- Forest and furniture products
- Metal Processing
- Paper products
- Recycling operations (metal, paper, and plastic recycling)
Types of Combustible Dusts
- Candy, sugar, spice, flour, grain
- Certain textile materials
- Coal and other carbon dusts
- Metal dust such as aluminum and magnesium
- Organic dust such as sugar, paper, soap, and dried blood
- Plastic dust
- Wood dust
- NFPA 654 (NEP) Compliance Audits- Consulting advice on explosion prevention and impartial guidance on choice and design of dust collection and explosion protection systems (relief venting, containment, suppression, use of inert gas, isolation techniques, etc.)
- Incident Investigation – Assistance with gathering complete, accurate and objective incident data to perform a cause and origin investigation.
- Dust Testing Recommendations – Provide recommendations of which combustible dust tests to conduct (Pmax, kst, LOC, MIE, MIT), how to interpret results, and what they mean to the user.
- Review of Practices – Assist with review of practice and provide recommendations on how to meet industry standards and how to minimize risk associated with combustible dust hazards.
Imperial Sugar, Port Wentworth.
(Feb. 7 2008, 14 fatalities)