PSM Oriented Towards Dust Hazards?
Posted by John Astad on May 29, 2009 at 10:23pm
Request Sent! View John Astad's blog
A process safety management (PSM) oriented program that addresses combustible dust hazards in the manufacturing, non-manufacturing, and utility sectors needs to be implemented as it is in the chemical and refinery sectors.
The main problem, is a disconnect concerning wood, food, paper, textiles, etc. process streams as not being considered like the 136 highly hazardous chemicals (HHC) as outlined in OSHA's Process Safety Management regulation (29 CFR 1910.119).OSHA National Emphasis Programs (NEP)Last year, the OSHA Combustible Dust National Emphasis Program (NEP) became effective four months after the Petroleum Refinery Process Safety Management (PSM) National Emphasi... There is a vast difference in the two OSHA NEP's with the goal of protecting the nations workforce and outlying communities from the harmful effects of industrial fires, explosions, and toxic releases.
In reviewing the background information for the Refinery PSM NEP, its disturbing when comparing and contrasting fatalities and catastrophes(FAT/CAT) between refineries and facilities that handle combustible particulate solids that generates combustible dust. For instance, on pg. 4 the Refinery NEP states:"According to OSHA’s IMIS database, since May 1992, 36 fatality/catastrophe (FAT/CAT) incidents related to HHC releases in the refining industry have occurred. These incidents included 52 employee deaths and 250 employee injuries, 98 of these injuries required hospitalization."Fatalities and Catastrophes (FAT/CAT)Over the same fifteen year period, according to the results of the Chemical Safety Board Dust Hazard Investigation, there were over 95 fatalities and hundreds of injuries as the result of over 160 combustible dust related fires and explosions in the manufacturing, non-manufacturing , and utility sectors. Basically there are three times as many fatalities and catastrophes (FAT/CAT) in sectors that generate combustible dust than in the refinery sector.
Yet Recognized And Generally Accepted Good Engineering Practices (RAGAGEP) and administrative control measures to protect the manufacturing workplace are dismally lacking. So is the rapidly diminishing manufacturing sector that provides a base for our national economic security even worth protecting? It doesn't seem so with the obvious inattention thats been misdirected elsewhere, to supposedly more urgent aspects of workplace occupational health and safety.
Highly Hazardous Chemicals (HHC)Combustible dusts have similar explosion severity (Pmax, Kst) effects as flammable liquids, gases, and vapors concerning destructive overpressure, thermal radiation, and ensuing projectiles. Facilities that maintain processes with over 10,000 pounds of flammable liquids and gases must consider these products as highly hazardous chemicals (HHC) as outlined in the OSHA's Process Safety Management regulation (29 CFR 1910.119).
So if combustible dusts have similar devastating explosive effects causing fatalities and catastrophes (FAT/CAT) like flammable liquids and gases, why aren't they listed as a highly hazardous chemicals(HHC)?
Wood, food, textiles, paper and many other seemingly harmless materials in manufacturing process streams are not considered toxic, reactive, or corrosive like the over 130 highly hazardous chemicals (1910.119 App A) under the Process Safety Management program. It's their combustible and explosive characteristics that need to be addressed as it is for flammable liquids and gases HHC (highly hazardous chemicals) in the OSHA PSM standards.
Recognizing the hazards of combustible dust is the first step through a process hazard analysis which is the foundation in lessening the occurrence and reducing the severity of future combustible dust related fires and explosions.
Once the hazards are identified and evaluated control measures can be implemented in similar fashion as outlined in the OSHA Process Safety Management program. A few of the measures in the current PSM with debatable input to a possible Combustible Dust PSM include:Operating ProceduresFor instance, the implementation written operating procedures addressing operating limits with consequences of deviation with steps to follow to correct deviations such as high operating temperatures. These operating procedures must include safety and health considerations concerning quality control for raw materials and control of dust emissions.
Additionally, precautions necessary to prevent combustible dust related fires and explosions, which also includes engineering controls, administrative controls, and personal protective equipment.Contractor ParticipationA process safety management program would also require contractor participlation.
Over the past year a large percentage of combustible dust related fires have involved contractors conducting hot work adjacent to process equipment. A Combustible Dust PSM would properly and proactively inform contract employers of the known potential combustible dust fire, explosion hazards related to the contractor’s work and the process. This would lessen the occurrence of future incidents.
Mechanical Integrity (MI)Mechanical integrity (MI) issues in a Combustible Dust PSM, would address the potential ignition sources that cause combustible dust related fires and explosions at facilities. For instance duct work, dust collectors, dryers, mixers, blenders, ovens, bulk storage enclosures are reoccurring problem areas concerning combustible dust related fires and explosions.
The refinery sector Mechanical Integrity PSM program addresses pressure vessels and storage tanks, piping, relief and vent systems and devices, and emergency shutdown systems controls. In contrast the manufacturing sector has bulk storage enclosures (silos, bins), pneumatic conveying duct systems, air material separators (dust collectors), in addition to relief and venting with explosion ventilation panels in reducing the severity of dust explosions.
Implementing written procedures to maintain the integrity of the above process equipment would provide employees with an overview of the mechanical integrity process and the combustible dust hazards that have been identified in a prior process hazard analysis. Process equipment inspection, maintenance, and testing would also be a vital aspect in the MI at the facility where deficiencies can be addressed in a proactive manner.
Incident Investigation Reoccurring incidents of combustible dust related fires and explosions have been a common theme in the manufacturing sector over the past year. This year, over 30% of incidents are repeats of prior fires and explosions at facilities. In many instance a combustible dust fire is a precursor to a a rare event, the combustible dust explosion.
Without proper incident investigation by the facility, the exact cause of the fire goes unnoticed and the combustilbe dust hazard remains present for the next preventable and predictable incident. A Combustible Dust PSM would identify the chain of events and causes where corrective measures such as Recognized And Generally Accepted Good Engineering Practices (RAGAGEP) can be developed and appropriately implemented.
Conclusion: Do I feel lucky?
The above examples are just a few proactive measures that could be crucial aspects of a Combustible Dust PSM that is similar to the current PSM utilized for facilities which process highly hazardous chemicals (HHC). Other measures in the PSM include Hot Work Permits, Emergency Planning and Response, Management of Change, and Compliance Audits. Many of the areas are already covered in the National Fire Protections Association (NFPA) combustible dust standards.Until combustible dusts are recognized as having similar explosive severity characteristics as flammable liquids and gases (highly hazardous chemicals) of the current OSHA PSM, preventable and predictable combustible dust related fires and explosions will continue to occur. Hopefully on a bit of borrowed time the next rare event will not be in the magnitude of the recent Imperial Sugar Refinery dust explosion. Like in the 1971 Dirty Harry movie, Detective Inspector Harry Callahan played by Clint Eastwood asks, "You've got to ask yourself one question: 'Do I feel lucky?"