Combustible dust is one of the most under-recognized risks in industrial settings. This is where EHS professionals can become a vital resource to identify and prevent explosions. Unfortunately, from aerospace and auto production to food processing and metallurgy, combustible dust is present in practically every manufacturing and industrial processing facility. This makes it essential to understand the dangers of combustible dust to mitigate any unwanted incident.
Confined Spaces and Combustible Dust
When finely dispersed, any flammable material can burn quickly. Even materials that do not burn in larger pieces, such as aluminum or iron, can be explosive in dust form if the right conditions are met. In fact, except for silicon and sand, all types of dust are potentially flammable to some extent.
The relative explosive severity of the dust is determined using a “deflagration index,” which compares them to other types of dust. They range from dust from egg whites and powdered milk, which can cause mild explosions, to dust from magnesium and aluminum, which can cause severe explosions. However, an explosion – no matter how small – is undesirable. This is especially true during confined space rescue operations.
Rescue Operations & the Role of Dust Explosion Pentagon
The dust explosion pentagon can help grasp the dangers of potentially combustible dust explosions. Rescue responders and EHS professionals use the dust explosion pentagon to measure the risks of an explosion. An explosion occurs when the following five factors are present:
- Combustible dust (Fuel)
- Source of Ignition
- The presence of oxygen
- The dispersal of dust (Suspension)
- Dust containment in a confined or semi-confined environment
When assessing a rescue situation, rescuers should search for any significant deposit of dust. Keep in mind that an atmospheric monitor with a flammable gas sensor will not be able to identify a hazard from dust.
When a dust pile is distributed and suspended in the air, it can become lethally explosive and explode as soon as an ignition source is provided. The explosion occurs due to the dust cloud rapidly burning, causing a quick rise in pressure in the contained region or restricted space. It goes out immediately or shortly after the ignition source is removed.
Considerations for Emergency Responders with Combustible Dust
In any rescue situation, the possibility of combustible dust, especially when venting an enclosure, building, or confined space, is almost always present. If ventilation causes dust accumulations, a safe space can become a ticking bomb. Therefore, emergency responders should always take the following steps to mitigate risks.
- Meet with the management team to learn about potential combustible dust concerns at their site before performing standby rescue tasks.
- Is there any information on the SDS (Safety Data Sheet) about the material’s potential to create combustible dust that should be reviewed?
- Familiarize yourself with the “deflagration index” for various materials.
- Consider the impact of ventilation in a space with explosive dust. As questions like whether the dust will be suspended as a result of your actions? Will your ventilation system or the static charge/discharge created by the suspended moving dust act as a source of ignition?
DCS Rescue Can Help Prevent Combustible Dust Explosions
Between 1980 and 2005, the Chemical Safety Board reported 281 combustible dust explosions in the United States. Countless more combustible dust settings are waiting for the variables to align and create the next deadly explosion. Therefore, it is essential to understand the risks in your response region to avoid accidents.
DCS Rescue can help safely conduct rescue operations in high-risk areas. We supply all necessary rescue equipment as well as the relevant planning and paperwork to meet confined space permitting regulatory standards.
Rescue plans are created on-site based on extensive assessments of the subject space and project demands if pre-planning is possible. Our rescue squad is transportable and available throughout the United States. Contact us today for more information.