Dust Collector Compliance with Combustible Dust Standards - Part 2 of 6

Agencies Involved

There are three key entities involved in combustible dust issues, each with its own particular area of responsibility:

NFPA: The NFPA sets safety standards, amending and updating them on a regular basis. As noted, when it comes to combustible dust, there are several different documents that come into play, as summarized in the section directly below. Together these standards add up to total protection to prevent an explosion,vent it safely, and/or ensure that it will not travel back inside a building. Most insurance agencies and local fire codes state that NFPA standards shall be followed as code. Exceptions would be where the authority having jurisdiction (AHJ), such as Factory Mutual, specifies an alternative safety approach which might be even more stringent.

This dust collector is equipped with an explosion vent with vertical upblast deflector plate. Other safety features include a sprinkler system and filters with special carbon-impregnated media for static dissipation.

OSHA: It is OSHA’s role, together with local authorities, to uphold the standards published by NFPA. In the aftermath of the Imperial Sugar Company explosion in 2008, OSHA re-issued its 2007 Combustible Dust National Emphasis Program (NEP) outlining policies and procedures for inspecting workplaces that create or handle combustible dusts. As defined by OSHA, “These dusts include, but are not limited to: metal dust such as aluminum and magnesium; wood dust;coal and other carbon dusts; plastic dust and
additives; bio-solids; other organic dust such as sugar, flour, paper, soap, and dried blood;and certain textile materials.” The revised NEP, which OSHA reissued on March 11, 2008, was designed to ramp up inspections, focusing in particular on 64 industries with more frequent and serious dust incidents.

According to an October 2011 OSHA update on its Combustible Dust NEP, since the commencement of inspections under the 2008 program, more than 2,600 inspections have occurred. More than 12,000 violations were found during this timeframe, including more than 8,500 which are classified as serious. Federal penalties and fines for these violations have totaled $22,738,909, with nearly another $1,600,000 in state fines. OSHA uncovered a variety of dust collection violations in these inspections, including dust collectors that were not equipped with proper explosion protection devices and systems that were not vented to safe locations. (Figure 1)

U.S. Chemical Safety Board (CSB): The CSB is an independent federal agency responsible for investigating industrial chemical accidents. Staff members include chemical and mechanical engineers, safety experts, and other specialists with chemical industry and/or investigative experience. The CSB conducts thorough investigations of explosions like the ones mentioned above – sifting through evidence to determine root causes and then publishing findings and recommendations. The CSB has a wealth of information on their web site (www.csb.gov), including educational videos depicting how combustible dust explosions occur.

 

 

Figure 1: Penalty graph shows fines imposed from commencement of the OSHA Combustible Dust National Emphasis Program (NEP) in 2008 until October 2011.(Image courtesy of www.oshalawupdate.com)

The CSB has become an outspoken advocate of the need for more stringent combustible dust regulations and enforcement. On February 7, 2012, the fourth anniversary of the Imperial Sugar explosion, the chairman of the CSB issued a statement in which he applauded the progress made to date in dealing with combustible dust issues. He noted, however: “Completing a comprehensive OSHA dust standard is the major piece of unfinished business from the Imperial Sugar tragedy…. We believe such a standard is necessary to reduce or eliminate hazards from fires and explosions from a wide variety of combustible powders and dust.” The CSB has also recommended that the International Code Council, which sets safety standards that are often adopted by state and local government, revise its standards to require mandatory compliance with the detailed requirements of the various NFPA standards relating to combustible dust.

The role of Congress: Some members of Congress are also advocating faster action by OSHA to implement a combustible dust standard. In February 2013, Representative George Miller of California, together with Representatives John Barrow of Georgia and Joe Courtney of Connecticut, reintroduced a bill titled The Worker Protection against Combustible Dust Explosions and Fires Act (H.R. 691). If enacted, it would require OSHA to issue an interim standard within one year of passage and the Secretary of Labor to issue a proposed rule 18 months later, with a final rule due within another three years. This is similar to another bill, H.R. 522, which was introduced in 2011 but never enacted. An earlier bill passed the House in April 2008 but never went to the Senate.

----------------------

In our next blog post, we'll take a look at close look at relevant NFPA standards. If you wish, you can download the entire white paper now.

Dust Collector Compliance with Combustible Dust Standards - Part 1 of 6

Combustible dust explosions are a risk in many areas of a plant, but one of the most common locations is the dust collection system. How do you know if your dust collection system complies? What do you do if it doesn’t? Are your employees at risk? What are the hazards and how do you identify them? This next series of blog posts are excerpts from the white paper How to Make Sure Your Dust Collector System Complies with Combustible Dust Standards.

The National Fire Protection Association (NFPA) sets standards and codes to protect buildings against fire and explosion risks, and the Occupational Safety & Health Administration (OSHA) is applying these standards with increasing vigilance. When it comes to combustible dust, several standards must be considered. This white paper reviews the current status of the OSHA National Emphasis Program for combustible dust, the NFPA standards that address how to prevent or limit explosion hazards, how to identify these hazards, and the types of equipment used to eliminate or control explosion hazards. We will also examine the most common shortfalls to compliance and how to avoid them.

The last decade: a look back

In January 2003, an explosion at the West Pharmaceutical facility in Kingston, North Carolina killed six workers and injured 38 others, including two firefighters. The culprit: inadequate control of dust hazards at the plant. Only a month later, in February 2003, another explosion and fire damaged the CTA Acoustics manufacturing plant in Corbin, Kentucky, fatally injuring seven workers. Investigators found that resin dust, accumulated in a production area, was likely ignited by flames from a malfunctioning oven, triggering the explosion.

The most famous combustible dust explosion in the past decade – and the one responsible for re-focusing the national spotlight on this issue – was the February 2008 accident at the Imperial Sugar Company’s Wentworth, Georgia refinery. A dust cloud explosion triggered a fatal blast and fire that killed 13 workers and injured 42 others, generating a storm of media attention and government scrutiny.

These dust collectors are equipped with passive and active controls. Passive controls are an explosion vent and ducting that control the pressure and flame direction, and a rotary valve that contains the flame in the hopper. The active control is a chemical isolation system mounted on the inlet duct. Triggered by a pressure/flame detector, it will extinguish a flame front passing through the inlet pipe before it goes back into the plant.

These are by no means the only fatal explosions to occur in U.S. manufacturing plants, though they are the three deadliest to be investigated. More recently, in December 2010, two brothers lost their lives in a chemical explosion at the New Cumberland, West Virginia plant of AL Solutions. And during 2011, three deadly fires and explosions occurred at a Hoeganaes Corp. plant in Gallatin, Tennessee. Investigators found that accumulations of fine iron powder in the facility led to the explosions.

In the U.S. alone in the 25 years between 1980 and 2005, the Chemical Safety Board reported 281 explosions caused by ignited combustible dust. These explosions resulted in 199 fatalities and 718 injuries. Combustible dust explosions over the past decade in U.S. plants are blamed for well over 100 fatalities and hundreds more injuries. Sadly, experts believe these accidents could have been prevented if the companies involved had followed best practices for fire and explosion protection such as the methodologies described in this white paper.

----------------------

In our next blog post, we'll take a look at the agencies involved in combustible dust issues. If you wish, you can download the entire white paper now.

Dust from Aluminium linishing processes

A global company involved in the avionics/ automotive sector, located on the West Coast of Scotland, is a leading global development partner in the avionics and automotive industry.

They offer unique systems competence regarding internal combustion engines and engine peripherals ranking among the top three systems suppliers worldwide for engine components such as piston systems, cylinder components and valve trains. Their facility in Scotland manufactures precision bearings for the automotive industry.

This company was using wet type dust extractors in their manufacturing area to control the dust from their aluminium linishing operations. There were several issues with these wet type dust collectors. They were noisy, inefficient and had to be cleaned out at least once a week. However, most importantly of all they did not comply with the local emissions regulations.

Their solution is based on a dust collector with 16 filter cartridges. As aluminium dust is highly explosive, the dust extractor had to be fully ATEX compliant. The dust collector incorporates an integral drop out section to remove large volumes of dust from the airstream prior to the air passing through the filter cartridges. This reduces the dust loading on the cartridges and so improves the filter life. Over 1000 kg per week of collected material discharges from the collector via three rotary valves into 1m3 flexible bags.

The dust collector was fitted with carbon impregnated filter cartridges, and was supplied complete with an access platform as well as an energy saving variable speed drive controlled by a differential pressure monitor. The system installed provides highly efficient extraction ensuring that ope¬rators are protected from exposure to dust generated during the linishing process.

Read more here about the Scottish Environment Protection Agency’s conclusion about the installation and also about improvement of working environment and reduced maintenance costs.