The Role of FR Garments in Mitigating Combustible Dust Hazards

FR garments also play a vital role in effective combustible dust hazard prevention.

• By Scott Francis
• May 01, 2020

As a hallmark of arc flash or flash fire mitigation programs, flame resistant (FR), arc-rated (AR) garments help protect employees against short-term thermal worksite hazards. These garments work together with other preventative safety measures to ensure industrial workers across various industries can remain safe while performing their job. What many do not realize is that FR garments also play a vital role in effective combustible dust hazard prevention and mitigation.

Simply put, combustible dusts are fine particles that can trigger serious incidents like explosions, deflagrations and flash fires. When paired with oxygen and heat, properly dispersed amounts of this type of dust acts as a fuel that rapidly combusts and causes a pressurized fire known as deflagration. Deflagrations in equipment or contained processes can lead to combustible dust explosions, which result when a deflagration encounters one additional pressure building element: containment. Since explosions can further disperse combustible dust throughout a facility, a chain reaction of secondary deflagrations can occur. Furthermore, a combustible dust incident can also cause flash fires, which may lead to second- or third-degree burns—even if a person is not in the direct vicinity of the original explosion.

Because combustible dusts are often made of organic or metal particles—plastic, food, textile, paper and metal dusts, for example—this hazard poses a threat across multiple industries. When equipment or process conditions enable dispersed combustible dust to act as fuel, there is a strong risk of a flammable or explosive incident should all four deflagration conditions or five explosion conditions present themselves. What is more, there is no uniting threshold level of dust accumulation needed to trigger an incident. Only a detailed risk assessment can identify a worksite’s specific hazards.

Using NFPA 652: Standard on the Fundamentals of Combustible Dust as the guiding consensus standard, safety managers must assess the dust hazards present within a worksite and determine if the dust is combustible, explosive or both. A DHA-Dust Hazard Analysis—which now must be completed by a qualified person per NFPA 652 before September 7, 2020—utilizes the hierarchy of risk controls to complete a thorough risk assessment. This assessment can help pinpoint a proactive plan that reduces the likelihood of a site combustible dust event through dust elimination; engineering controls, like venting or suppression; and administrative controls, like housekeeping. One final control—the use of personal protective equipment (PPE)—turns the focus from proactive and preventative measures to defensive, mitigative measures.

If the immediate and most recognizable threat facing those working around combustible dusts is an explosion, why then is PPE, and in particular FR garments, so important?

It is well-known that FR garments are not shields and cannot protect a worker within a blast radius. They can, however, serve as critical safety linchpins, helping close the risk gap and mitigate the potential for injury or loss of life. FR garments can also help extend escape time so that employees can quickly and safely retreat from an incident.

With this in mind, we explore three proof points that make a strong case for incorporating FR garments into combustible dust safety programs.

Fire is Present in a Combustible Dust Incident

Whether through deflagration or flash fires, industrial workers face serious burn risks should a dust incident occur. It could be a single deflagration, or a chain of flash fires, but a combustible dust incident ignites these dust particles and creates an unstable situation where fire can easily spread throughout a worksite.

Why FR garments? Non-FR clothes ignite and continue to burn long after a flame source is removed, acting as the fuel that ignites and continues to burn long after the thermal source is removed. FR garments combat this issue through its functionality—these garments self-extinguish once a flame source is removed and provide sufficient insulation from second- and third-degree burns. While FR garments cannot prevent burns entirely, it can help drastically reduce the severity of burn injuries and significantly increase the probability of survival.

Burn Injuries are Serious Injuries

Pulling data from the U.S. Chemical Safety Board, there were 281 combustible dust incidents between 1980 and 2005, which resulted in 119 fatalities and 718 injuries. A 7:1 ratio over fatalities, burns accounted for many of combustible dust-related injuries. These injuries—often catastrophic in nature—can have long-term repercussions, and some fatalities have underlaying causes in burn injuries.

Why FR garments? Through their insulation properties, FR garments can help alleviate overall burn injuries and lessen life-threatening scenarios. In use alongside other PPE, such as gloves and goggles, FR garments can help reduce burn injuries if worn correctly and may help lower fatalities from burn injuries. FR PPE will not protect against the concussive force of the explosion, but it will certainly mitigate burn injuries caused by deflagrations and flash fires.

The Onus is on Employers

Following high-profile combustible dust accidents over the past decades, OHSA issued the Combustible Dust National Emphasis Program (NEP) in March 2008. Many felt a formal final rule on combustible dust would be issued shortly after, but none have been issued.

Just because there is no OSHA Final Rule on dust, however, does not excuse employers from implementing required protection programs. OHSA points to its General Duty Clause: 5 a 1, mandating that employers provide a workplace where workers are protected against recognized hazards, and other regulations like CFR 1910.1200: Hazard Communication and Training as the necessary regulations to push combustible dust hazard compliance. The NEP aggressively inspects facilities and enforces existing regulations where potential catastrophic combustible dust events could occur, thereby notifying employers to their worksite’s potential combustible dust hazards. Once they are aware of the risks, employers must use “how to” tools at their disposal, such as NFPA consensus standards, to prevent and mitigate combustible dust hazards.

Why FR garments? The latest edition of NFPA 652 (2019): Chapter 8 has an extensive section on PPE and flame-resistant clothing selection to build protocol based on the results of the combustible dust and flash fire risk assessment. Specifically calling attention to FR garments, this standard sets the basic groundwork for selecting appropriate PPE to reduce burn injury if an event were to occur. FR garments, especially FR daily wear, offer streamlined and consistent protection when worn and worn correctly. FR daily wear also acts as a continuous reminder to work safely and don appropriate task-based PPE in addition to providing some level of constant body thermal protection in a garment that mimics the style and comfort of streetwear.

While not immediately associated with the combustible dust hazard, FR garments are now quickly becoming a critical tool to not only adhere to the latest NFPA standards but also to create a holistic employee protection plan that accounts for proactive and mitigation efforts. An indisputable final layer of defense, FR garments clearly have their place in the combustible dust hazard mitigation conversation.

This article originally appeared in the May 2020 issue of Occupational Health & Safety.