Are your dust characteristics explosive? If you are dealing with combustible dust, learn how to prevent a serious explosion from happening, the vital role a preventative maintenance plan plays in prevention, and the regulations industries must comply with.
Learn how to limit or prevent your dust from causing a serious explosion.
Are your dust characteristics explosive? If you are dealing with combustible dust, how do prevent a serious explosion from happening? Having the answers to these questions, and implementing a preventative maintenance plan, will help you avoid a serious dust collector emergency.
What is combustible dust?
Combustible dust can be defined as any fine material that has the ability to catch fire and explode when it’s mixed with the proper concentration of air.
When can combustible dust create an explosion?
When the right conditions are in place, combustible dust can become hazardous and create an explosion. Dust can collect on multiple surfaces in a facility (e.g. ducts, crevices, dust collectors, equipment, etc.), and once this build up of dust mixes with the right conditions, it only takes a small ignition source to create a significant explosion. There are even scenarios in which combustible dust can self-ignite. This usually results from static that builds up as the particulates rub against one another.
Who does it affect?
Combustible dust effects a wide variety of industries such agriculture, metalworking, mining, chemicals, plastics, pharmaceuticals, etc. Industries that are susceptible to combustible dust are regulated by OSHA standards and NFPA guidelines.
How can I prevent a dust collector fire?
Now that you know what conditions required for combustible dust, when it can happen, and who it effects, how do you limit or prevent a serious explosion from happening? Your best plan of action is going to include steps that are proactive instead of reactive. Here are the proactive steps you can take:
- OSHA Standards: Ensure you are meeting OSHA’s set of standards regarding combustible dust. Industries that are susceptible to combustible dust are regulated by OSHA standards When you implement OSHA’s set of standards, you are creating a safe working environment, avoiding property and economic loss from an explosion, avoiding regulatory fines.
- NFPA Guidelines: Make sure you are meeting codes outlined by the NFPA (National Fire Protection Agency). The NFPA publishes a list of guidelines that will help you minimize injury or death from combustible dust. The following codes are related to the most combustible types of dust (e.g. sugar, wood, fine aluminum):
- 664, Standard for the Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities
- 484, Standard for Combustible Metals
- 61, Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities
- Preventative Maintenance Plan: Properly maintain your facility and dust collector to help prevent a build up of dust. Clean up any excess dust build up on your dust collector, other equipment, vents, and filters.
- Explosion Vents: Installing an explosion vent on your dust collector is one strategy in minimizing the damage to your equipment or employees who are nearby. The purpose of an explosion vent is to provide an alternative route for flames and expanding gases. It relieves internal pressure, and ruptures the moment pressure has been exceeded in your dust collector.
- Explosion Latches: Latches operate under the same concept as explosion vents. Latches provide venting in the event of an internal explosion.
Dust Collector Change Out Check List
For a small woodworking shop, Is an explosion venting device must be required for dust collector with capacity under 5000 CFM (300 to 4900 CFM)? Under what circumstance can explosion venting not require? Is there some dust collector without explosion venting can be purchased and installed? Can explosion venting be installed at a dust collector (used dust collector) with ease?
Thanks you for reaching out to us. In response to your questions, please see below.
Is an explosion venting device required for smaller dust collectors?
-If the dust collector is required by an AHJ to meet NFPA design guidelines, any dust collector with an internal dirty air volume of 8 cubic feet or larger must have explosion protection equipment in place if it is handling an explosive dust. This can be accomplished with explosion venting, chemical explosion suppression, or by designing the vessel in such a way that it can contain the explosion pressure.
When is explosion venting not required?
-It is important to differentiate the difference between “required” and “necessary”. Whenever there is a presence of explosive dust in an environment that an oxidizer and ignition source may be present, there is the possibility an explosion event may occur. Due to this, it is the opinion of U.S. Air Filtration that explosion protection equipment is necessary whenever an explosive dust is being collected in an environment where it can be ignited. Determining if explosion protection is required is an application and customer specific question. For industrial applications, it is standard practice to complete a Dust Hazard Analysis to determine if the conditions are present for an explosion risk. It is then the responsibility of the customer and their AHJ to interpret the Dust Hazard Analysis and determine if explosion protection equipment is necessary for their operation.
-From a technical perspective, four things must be present in order for a dust collector to be considered at-risk of explosion:
o Oxygen or oxidizer
o Ignition source (sparks, electrical short, static electricity)
o Fuel (dust with a KST value greater than 0)
o Vessel dirty air volume greater than 8 cubic feet
If all of these have the ability to be present, even in an upset condition, explosion protection equipment should be considered necessary.
Can a dust collector be purchased without explosion venting?
-Absolutely! Every base model dust collector offered by U.S. Air Filtration is without explosion protection equipment in it’s base model form. Our engineering team works with every customer on a case-by-case basis to properly size and select explosion protection equipment when necessary that best fits the customer’s needs. Once an explosion protection equipment design direction is chosen, our engineering team will incorporate the necessary changes to the dust collector.
Can explosion venting be added to a used dust collector?
-Yes, but there are some important considerations to take into place before beginning this process. Explosion venting is not one-size-fits-all. To determine how much explosion vent area is required to safely relieve the explosion gasses without over pressuring the dust collector, multiple calculations must take place. These calculations involve variables such as dust properties and dust collector dimensions. In order to properly retro-fit explosion venting to an existing dust collector, these calculations are required. Physical modifications to the dust collector would be required, including adding penetrations in the dirty air plenum and welding on explosion vent flanges.