Safety Insight: A Filter/Receiver Dust Explosion
A filter/receiver directly connected to a powder milling operation exploded giving rise to an indoor deflagration, which, fueled by powder deposits, propagated into three floors of the facility. Fortunately no one was injured, however, the filter/receiver was destroyed by the explosion and several other pieces of equipment were damaged by fire. Windows were blown into a courtyard from three floors of the building. A deflagration in the courtyard caused damage to several building windows.
A mill bearing failure caused overheating of the powder and creation of embers, which entered the filter/receiver and initiated a primary dust/air explosion. Dust accumulations in the explosion relief discharge ductwork caused delayed activation of the relief door and over pressurization of the filter/receiver. Poor housekeeping had allowed significant dust accumulations on floors and overhead surfaces.
The root cause of this incident was “less-than-adequate recognition of dust explosion hazards (Dust Hazard Analysis)” including:
- Less than adequate housekeeping (Management Systems),
- Less than adequate preventive maintenance of rotating equipment (Mechanical Integrity),
- Less than adequate monitoring of mills (DHA),
- Less than adequate explosion relief system and system maintenance (Mechanical Integrity)