Combustible Dust Testing & Remediation Definition
At present there is no universal definition for combustible dust.
The OSHA NEP defines it as “particulate solid that presents a fire or deflagration hazard when suspended in air or some other oxidizing medium over a range of concentrations, regardless of particle size or shape.”
The NFPA defines combustible dust as follows:
"A finely divided combustible particulate solid that presents a flash fire or deflagration explosion hazard when suspended in air or some other the process specific oxidizing medium over a range of concentrations., regardless of particle size or shape."
Most solid organic materials, as well as many metals and some nonmetallic inorganic materials, will burn or explode if finely divided and dispersed in sufficient concentrations.
Dust Explosion Pentagon
There are five basic elements needed for an explosion:
- A fuel is needed to burn (combustible dust)
- Oxygen is needed to sustain the fire (air)
- Heat from an ignition source is needed (spark)
- A high concentration of dust is dispersed into the air (deflagration)
- The dust must be confined within an enclosure or structure (explosion)
Enclosed conveyor belt with dust build up inside
Primary explosion from motor sparking creates a dust cloud inside enclosure
Dust cloud ignites causing much larger secondary explosion