NFPA Discusses Proposed Changes to Combustible Dust Hazard Standard
During day two of the NFPA Conference and Expo, Guy Colonna, assistant vice president of fire protection applications for NFPA, discussed proposed changes to the NFPA 654 standard, which provides the fundamental fire and explosion protection requirements for evaluating and controlling combustible dust hazard conditions.
The 2011 revision focuses on determining the factors that contribute to a dust hazard condition for both fires and explosions, including dust layer thickness. Colonna said regulations should move away from the 2006 standard’s layer approach, making aware that single layer thickness is inadequate to represent all possible applications.
The proposed revision also focuses on adding new criteria, including structural integrity requirements and a 95 percent occupant survivability rate (flash fire criteria) that would control the quantity of dust accumulations by protective garments. Colonna said the committee has proposed additional changes that would require the source of dust to be determined. Dust sources can come from processes, handling, or conveying.
Colonna explained that dust explosions are caused by a complicated mix of properties including fuel, ignition, dispersion, oxygen, and confinement. “You can’t look at one single property for dust explosions,” Colonna said. “A good goal is to control the fuel and ignition hazards.” Colonna said it is important to consider a room’s proportion or volume that could be filled with a combustible dust concentration, as well as the percentage of an area that could be filled with dust.
The Association Technical Meeting meets at 2 p.m. today in Mandalay Bay Ballroom EFGH to discuss the proposed changes to NFPA 654.