What is NFPA 652?

what is nfpa 652

As a general contractor, architect, engineer and any other profession in the construction industry, have probably encountered NFPA’s 652 and the requirements for a Dust Hazards Analysis (DHA), at some point during one of your project. Now that we are at the end of August, Hughes wanted to remind you a DHA is to be completed by September 7, 2020. That’s right around the corner! But what exactly is a DHA and what are you looking for?

In NFPA 652, the term “Dust Hazards Analysis” or DHA was introduced when it was originally issued in 2015. Its purpose is to give personnel a single source for information on the fundamentals of safe handling combustible dust and powders in an industrial setting. The principles discussed within NFPA 652 focuses on fuel containment, controlling ignition sources and limiting the spread of a combustible explosions by identifying potential risks in the process. These are the elements that can be found by conducting a DHA, which will need to be updated at least every 5 years.

 

The DHA will identify the following conditions that may exist, whether it be external or internal to the system that contribute to a fire hazard.

  1. Oxygen: We all need oxygen, and unfortunately, fire also needs oxygen in order to burn.
  2. Combustible Dust (fuel):  According to OSHA (Occupational Safety Health Administration), combustible dusts include those made from food products such as apple, carrot, cocoa powder, cotton, gluten, and/or potato. Carbonaceous dusts such as charcoal, cellulose, cork are also combustible. Chemical dusts such as calcium acetate and dextrin, and metal dusts such as aluminum, magnesium, and zinc are also on the list. Plastic dusts from epoxy and melamine resins are also considered highly probable of producing a dust explosion. This dust can be found in places such as, floors, elevated surfaces, inside the ductwork, inside process enclosures and on top of machines.
  3. Dispersion: When the pile of dust is just sitting there it doesn’t create much of an explosion hazard, even though it does create a fire hazard. It isn’t until the accumulated dust is dispersed throughout the oxidized air that it creates an explosion hazard. Dispersion can happen from a pulse cleaning inside dust collector, the use of compressed air for cleaning, and any events that can disturb dust from elevated surface.
  4. Ignition(heat, spark): However, the airborne dust is nothing more than a dust cloud until it comes into contact with an ignition source. These ignition sources can vary, and what is needed to ignite the cloud depends on what the dust is made from. Some dusts can ignite just from touching hot machinery, while other dusts ignite after being exposed to a small fire, spark, static electricity, or even a lit cigarette. Some materials, such as magnesium, are even able to create enough heat by themselves to self-ignite.
  5. Confinement: When the dust cloud is confined in a closed area it does not have the air movement from wind to disperse it; dust particles can instead stay suspended in the air for days at a time. This allows the levels of dust particles in the air to increase and provide more fuel for the resulting explosion. Dust can be confined is areas such as, inside pipes, inside dust collectors, and inside any process enclosure or machines.

 

Taking on a DHA for your facility can be a daunting task, but it is one that is necessary to recognize any potential hazards. However, if you take it one step at time, you can make your way towards having a safer operation. The DHA should help you develop a plan of action to maintain good housekeeping, safety training to your employees and properly protected equipment and electrical components.

 

Hughes Environmental has performed combustible dust cleaning in a wide array of facilities throughout the United States and deals with many types of combustible dust.

Hughes Environmental abides by standards set by the NFPA, NADCA, and OSHA when performing combustible dust cleaning and uses equipment approved for combustible dust cleaning, such as intrinsically safe vacuums and grounded hoses.

Contact Hughes Environmental today to schedule your combustible dust cleaning; call: 888-845-3952 or complete your request online.