Michael Courouleau explains that there are many items
that are considered fire hazards in an industrial environment. These substances
may become explosive or combustible when suspended in air at a certain
concentration. According to Michael
Courouleau, materials that may form combustible dust include wood; coal;
carbon; food; fertilizer; tobacco; paper; soap; rubber; cotton; drugs; dried
blood; dyes; certain textiles; and metals of aluminum and magnesium.
The recognition of combustible dust hazards became
widely known after several major grain elevators exploded within days of each
other, reports Michael Courouleau. These bursts were catastrophic in proportion
halting operations and causing loss of life. Michael Courouleau says a
potential cause of these incidents is a product is being manufactured called
petroleum coke, which is used at power plants and cement plants. It is a lower
cost substitute for a portion of the plant’s coal supply and is used for power
generation in coal fired boilers, explains Michael Courouleau. This product is
in question whether it has combustible qualities when suspended in air like the
materials listed above.
After the deadly grain dust explosions occurred, OSHA
developed Grain Handling standard 1910.272. The federal government says that
the issue is nationwide and more than 130 workers have been killed and more
than 780 injured in combustible dust blasts since 1980 (OSHA Report on Sugar Explosion,
2008). Even with these news measures there have been issues, says Michael
Courouleau. For instance, the most recent explosion was in 2008 at the Imperial
sugar refinery in Port Wentworth, Georgia. In all, 14 people lost their lives
in this incident alone, laments Michael Courouleau.
The December 1977 Westwego Continental Grain elevator
explosion killed 36 people and is the deadliest grain dust explosion to have
occurred in modern times, recalls Michael Courouleau. The blast destroyed 48 of
the 73 giant silos used to store grain.
Michael Courouleau clarifies that most of the men that died got trapped
in a two-story cinder block control room building that was crushed by a nearby
25 story grain silo.
According to Michael Courouleau, other massive and
devastating explosions occurred at the Archer Daniels Midland facility and
another grain-dust explosion in Galveston, Texas, killed nine workers.
OSHA‘s Grain Handling regulations are set to minimize
the presence of combustible dusts. The NFPA has published recommended fire
protection standards which can be adopted by the Authority Having Jurisdiction
(AHJ). Special fire hazard protection
systems, maintenance, and training programs must be in place to prevent loss of
life and property from reoccurring due to combustible dust.
The Fire Triangle
There are 3 major components, Michael Courouleau
notes, often referred to as the Fire Triangle. These are essential elements in
having a fire or explosion. These consist of an ignition source, fuel, and
oxygen. The suspended combustible dust is the fuel to the explosion. Michael
Courouleau goes on to say that there is potential ignition source at every
plant, including:
- Equipment that could cause sparks/ heat sources
- Improper clothing
- Hot work processes
- Failure to utilize intrinsically safe tools
- Rotating equipment
- Electrical equipment
Oxygen must also be present in the atmosphere to
support combustion.
Combustible dusts are measured by explosive severity,
or Kst; maximum explosion pressure, Pmax; and minimum ignition energy.
MIE. Michael Courouleau explains that
these measurements relate to the chemical properties, flammable characteristic
of material suspended, particle size, and concentration of the material that is
flammable.
Michael Courouleau is
an environmental safety expert with extensive experience in the field. He warns
that many cost-cutting measures in industrial manufacturing may cost more in the long
run…including lives.
