A Guide to Combustible Dust Hazard Prevention
Combustible dust explosions cause dozens of injuries and kill several people every year. They can destroy factories and bankrupt businesses.
2008 Imperial Sugar Refinery Explosion
A combustible dust explosion at a sugar factory in Georgia killed 10 people.
Photo Credit: U.S. Chemical Safety and Hazard Investigation Board, Public domain, via Wikimedia Commons.
Combustible dust suspended in the air presents serious health and safety risks, and you must mitigate these risks where possible.
But what exactly is combustible dust, and how can you keep your facility safe? Continue reading to learn more.
What Is Combustible Dust?
Combustible dust is a substance made up of combustible particulate solid that, under certain conditions, can become highly explosive. This means it presents a serious fire or deflagration hazard, and as such, measures need to be taken to prevent an explosion.
This dust can accumulate over several years as a result of standard manufacturing processes in the workplace.
It can build up anywhere, even in hard-to-reach places, making it difficult to clean and remove.
Even a small amount of combustible dust can cause a significant explosion if exposed to an ignition source.
Understanding what materials create combustible dust, and what you can do to prevent explosions, is key to the safety and health of everyone who may be present in such areas.
Materials Classified as Combustible Dust Hazards
There is a wide range of materials that can become combustible dusts under the right circumstances. Somne of these materials include:
Wood
Textiles
Rubber
Pesticides
Pharmaceuticals
Sulfur
Coal
Sugar
Flour
Cornmeal
Grains
Powdered milk
Egg whites
Metals can form combustible dusts, too. And their explosions can be just as dangerous as organic materials.
Any industry or facility that uses products and processes that have the potential to create combustible dust must take measures to reduce the risk of explosions.
How Do Combustible Dust Explosions Occur?
Five things must be present for a combustible dust explosion to take place. These are:
An ignition source
Dispersion of dust particulates
Confinement of the dust cloud
Oxygen
The combustible material
These are sometimes represented as a "dust explosion pentagon".
The dust must be dispersed in a confined space, as that confinement creates the pressure necessary for an explosion. Dust explosions generally occur in two stages.
Primary Explosion
This is the first wave that is caused by a heat source or ignition in an area where the concentration of dust in the air is "just right". This will often be inside some sort of processing equipment where a lot of heat is present.
This dust burns very rapidly, releasing gases and increasing the pressure in the enclosed space, causing an explosion.
Secondary Explosion
The first blast might stir up dust that has settled over time. This might be in a variety of locations, including on top of equipment, support beams, rafters, or other ledges.
This dust becomes suspended in the air, and can then ignite, creating another explosion. This secondary explosion is often more destructive than the first as there is usually a much larger volume of dust.
Identifying Risks
Before you can take steps to prevent a combustible dust hazard, you need to know how to spot them.
Remember that combustible dust explosions rely on the presence of the explosion pentagon. Knowing how and where to spot each the five risk factors for combustible dust explosions is the first step in assessing the risk of an combustible dust explosion.
Does Your Operation Produce Dust?
The first thing you should do is determine whether your firm creates, produces, or works with any combustible dust-producing materials.
Combustible dust is a potential hazard that exists in most lines of work. The dust may be produced as a side effect of a variety of tasks such as sawing, crushing, mixing, or transportation.
What Are Your Potential Fire or Ignition Sources?
The next area to inspect is any potential fire or ignition sources. Keep in mind that these might also be fire risks owing to non-combustible dust explosions, so pay close attention.
Where Could Dust Be Hiding?
You should look for dust spots in particular locations that are difficult to clean, especially wherever you can't reach.
How Good Is Your Ventilation?
Think about pressure and ventilation in these areas and how much of a risk is present.
Oxygen Is Difficult To Avoid
Of course oxygen will always be present in any ambient area, so this is one risk factor that you can't really remove.
Preventative Measures
One of the best and easiest ways to avoid a combustible dust explosion is to maintain a good housekeeping program.
Dust can accumulate anywhere quite easily, but in many situations, it is also very easy to clean. The better dust is cleaned, the less risk there is of an explosion.
You should implement dust removal systems and set a schedule of regular inspections. Ensure that anyone responsible for cleaning any work areas is doing so properly and that they are aware of the risks that uncleaned dust can cause. Nobody wants to explode at work.
Something else that is very important is making sure all electrical equipment is working properly and in good condition.
Faulty electronics could easily produce high temperatures that could lead to the ignition of combustible dust.
The same goes for any heating system. Any equipment that generates heat should be inspected regularly by a professional to maximize safety.
If you have any systems or equipment present that generates an open flame this should be regulated and monitored very carefully.
To further reduce the risk of an explosion you could implement misting devices. These systems are similar to the pedestrian misters you might encounter on a hot day.
Misters can help to stop dust from dispersing, reduce heat, and add moisture to the air. But depending on your facility and process, misters might not be an option.
One final crucial thing is to ensure all employees have all the necessary training and PPE.
Eye protection, respirators, and any other protective equipment should be provided as standard to help keep workers safe at all times.
For any combustible materials that are present in your workplace, you can provide a safety data sheet.
Your employees can refer to this for any necessary information in terms of the safety risks such materials present.
Mitigating the Risks of Dust Suspended in the Air
Taking all of these precautions can be quite difficult, and if it is not done properly, the risk of an explosion will still be present.
ReadyLimit has decades of experience in providing workplace hazard solutions and addressing combustible dust hazards at facilities across the country.
We also assist our clients with other issues — not just problems with combustible dust suspended in the air. We're experts at fire code analysis and proper building design, water treatment, and process flow.
What are some unique places you think that combustible dusts might exist in your facility? Let us know in the comments below.
To find out more about how we can help you contact us today.
