The Creation of Combustible Dust
Combustible dust in facilities can cause serious danger or harm if not controlled the proper way. Many bulk material handling facilities find themselves processing materials that naturally produce levels of dust putting the workplace in danger.
According to Bulkinside, if a facility handles dry materials, there could be unique fire, explosion, and toxicity hazards. When materials are in a consolidated form, there is an increased hazard level when converting to powders and granules. Having a clean facility is always going to help mitigate risk, but there is only so much you can prevent without the proper dust mitigation equipment.
Materials go through a variety of processes that can increase the risk of dust, and therefore an explosion, including crushing, mixing, sifting, or screening. Even the transport of materials throughout a plant could cause dust to occur.
The Regulations Surrounding Dust
The National Fire Protection Association (NFPA) is the leading information and knowledge resource on fire, electrical, and related hazards.
NFPA 652, Standard on the Fundamentals of Combustible Dust, makes the owner or operator of the plant responsible for the following:
- Characterizing the combustible materials in the facility.
- Identifying combustible dust hazards associated with those materials.
- Mitigating identified hazards.
- Communicating those hazards to the workforce.
While NFPA does not regulate this themselves, OSHA, fire marshals, building inspectors, and insurance underwriters enforce NFPA 652. It is critical to understand and follow the regulations for not only the safety of your workplace, but also to avoid fines.
OSHA does issue citations to plants solely for the presence of dust in their facility, so this is not an issue to take lightly. Recently it was reported that a plastic recycler was fined $88K from OSHA for identifying combustible dust hazards that were not mitigated appropriately. There were dangerous amounts of combustible dust built up on surfaces that could possibly ignite with the open electrical equipment in the same area.
dust hazard analysis (DHA) basics
It is always recommended to know exactly what materials are in a facility. To determine if any of the materials will generate combustible dust, an inventory of the powdered materials should be created. Identify which materials are combustible and which are not. A literature search can help during the process if you are unsure. Most concrete evidence of combustible vs. non-combustible will be generated through laboratory experiments.
If materials are combustible or explosive, then a DHA must be completed. NFPA promotes three fundamental principles:
- Controlling the Fuel
- Controlling the Ignition Source
- Limiting the Spread of a Combustion Event
A DHA will be employed to identify the combustible dust hazards that are present. This is a documented, systematic evaluation of each piece of equipment and building that handles or contains combustible dust material, identifying if explosion, flash fire, or fire hazards exist. These evaluations should be completed by a trained professional. Current administrative and engineering controls that are used to manage these hazards will also be reviewed, and additional recommendations will be made.
Conducting a DHA is not only required, but will mitigate risk for the personnel and facility, along with offering cost savings over time. Safety training with specific modules relating to combustible dust should occur for all employees and contractors. Job specific training should be provided for those working with combustible dust.
After successfully completing a DHA for your plant, the DHA should be reviewed and updated at least every five years. If your facility has undergone any renovations or changes, you should also have the DHA reviewed and updated as needed.
Working with a qualified systems integrator who can complete your DHA along with recommend and provide dust mitigation solutions can expedite the solutions phase of the process. Dust mitigation solutions may range from a dust control program to a full dust collection system or XP venting.
As a full-service process engineering firm, Spec’s experts can conduct a DHA for your facility. We provide a turnkey DHA solution – assisting with identification, characterization, and mitigation of combustible dust hazards in your facility. Steps throughout the process would include a site evaluation, material testing, detailed report of finding, PFD and GA drawings, equipment lists, instrumentation lists, RFQ package, and TIC estimate.