Industrial dust explosions are a serious hazard that can occur in a variety of industrial settings. These events can cause extensive damage to property, equipment, and even life. In order to minimize the risk of dust explosions, industrial manufacturers must understand the causes, flammability of dust, and the codes and standards that apply to industrial dust explosions. In this blog, we will discuss several dust explosion safety topics, including:
- Why Dust Explosions Occur at Industrial Sites
- Dust explosion safety
- The Importance of Explosion Safety for industrial manufacturers
- What is ATEX?
- How to determine the flammability of industrial dust?
- How to evaluate the potential of a dust explosion
- How to reduce the effects of industrial dust explosions
- Finding the best possible solutions to reduce dust explosion effects
Why Dust Explosions Occur at Industrial Production Sites
Dust explosions can occur in a variety of industrial settings. These events are typically caused by the ignition of a combustible dust cloud in an enclosed space. This can be caused by a number of sources, including sparks, open flames, or electrical currents. Furthermore, dust explosions can also occur due to improper dust extraction, ventilation, inadequate suppression systems, or the accumulation of dust on surfaces by lack of source extraction.
The use of standard dust filters, often results in over-extraction or under-extraction due to unbalanced emission control. Especially for larger sites and more complex production processes, standardized solutions will not suffice. This may lead to explosion risks in various industries. It’s not the first time the news reports a Chemical Explosion, hazardous Flour dust bomb or Sugar Dust Explosion.
To reduce the risk of a dust explosion, manufacturers must take steps to ensure that potential ignition sources are eliminated, and that proper Dust Collection Systems with suppression systems are in place.
Dust Explosion Safety
Dust explosion safety is essential for industrial manufacturers. Dust explosions can cause extensive property damage, and if not properly controlled, can even cause fatalities. The first step in dust explosion safety is to identify the potential ignition sources in the area. This includes any sources of heat, sparks, open flames, or electrical currents. Once these sources have been identified, manufacturers must take steps to reduce the risk of a dust explosion. This includes following safe work practices, such as avoiding activities that create dust clouds and keeping combustible dust away from ignition sources. Knowing how to select an effective dust filtration system also helps with proper dust explosion prevention.
The Importance of Explosion Safety for Industrial Manufacturers
The importance of dust explosion safety for industrial manufacturers cannot be overstated. To reduce the risk of a dust explosion, manufacturers must understand the ATEX Directive, the flammability of dust, and take appropriate steps to reduce the risk of a dust explosion. This includes following safe work practices, installing proper dust extraction, ventilation and suppression systems, and regularly inspecting equipment for potential ignition sources. Also, the importance of selecting the right, ATEX Certified Equipment is often overlooked.
What is ATEX?
ATEX is an abbreviation for ATmosphere EXplosible. Also, the name ATEX is used for two European guidelines (ATEX 153 and ATEX 114) concerning explosion-proof electrical placement and mechanical equipment. The ATEX Directive, also known as the ’94/9/EC Directive’, is a set of European Union regulations that were created to minimize the effects of industrial dust explosions.
The ATEX Directive contains safety requirements for all electrical and non-electrical equipment used in European locations where explosive atmospheres may be present. This includes areas with combustible dust, liquids, or gases. The ATEX Directive is implemented through the use of certifications and testing procedures to ensure that equipment is designed and constructed to meet safety requirements.
ATEX designates hazardous materials such as explosives, but also dust. It imposes requirements for companies that handle and transport these materials. Therefore, requiring companies to protect employees from explosion risk.
How to Determine the Flammability of Industrial Dust?
In order to determine the flammability of dust, industrial manufacturers must first understand the combustible dust classification system. The combustible dust classification system divides dusts into four categories:
- Class 1 (explosible dusts)
- Class 2 (non-explosible dusts)
- Class 3 (sterile dusts)
- Class 4 (flammable dusts).
Each of these categories has different properties and characteristics that determine how it would react to an ignition source. For example, Class 1 dusts are the most explosive, while Class 4 dusts are the least explosive. Once a manufacturer has identified the type of dust, they can then take steps to reduce the risk of a dust explosion.
How to evaluate the potential of a dust explosion
There are many parameters to evaluate the potential impact of a dust explosion. These parameters include the following:
- Kst Value: used for measuring pressure rise
- Pmax: used for maximum pressure
- MIE & MEC: used for minimal energy required to ignite and for the smallest amount of dust concentration needed to cause an explosion
- MESG: used for maximum sound pressure of an explosion
- TLayer: measures dust layer thickness needed for an explosion to occur
- T5mm: for the minimum temperature certain dust needs to ignite
- Pred: determines the maximum rate of pressure rise that can be produced during an explosion
All of the above are used to evaluate the potential for a dust explosion and to identify the most effective mitigation strategies. Additionally, they can all be determined through testing or through mathematical models. By understanding these parameters, industrial manufacturers can take steps to reduce the risk of a dust explosion and ensure the safety of their assets and personnel.
What is a Kst Value?
To clear the air on the abbreviation: K is a mathematical shorthand for a constant, st stands for ‘staub’ – the German word for dust. Kst value is an internationally agreed rate of pressure rise, which is one of the parameters that expresses the parameters of the possible severity of a dust explosion. Which means different powders have different explosion risks. This can be calculated using the fomula:
Kst = (dP/dt)max * V1/3 .
We classify powders into groups, called St classes, as follows:
|Powder Class||Kst Value [bar.m/s]||Comment|
|St0||0||Does not explode|
|St3||>300||Very Strong explosion|
What is PMax Value?
Pmax is the maximum pressure (P) that can be produced by a dust explosion. It is a critical parameter for dust explosion safety, as the magnitude of the pressure produced by an explosion can lead to extensive damage to property and equipment.
PMax values are determined through testing, or by using mathematical models to predict the explosive pressure of a dust cloud. When designing systems for dust explosion safety, it is important to consider the PMax value of the dust to ensure that the system is adequate for the task.
Once an explosion starts, heat is produced which leads to increase in pressure. Pmax, therefore, is measured by dispersing a material in a 20-litre spherical testing chamber. Pmax value is measured with the basic unchanged equation: PMAX = (tJ – tA).
What is MIE & MEC?
Minimum Ignition Energy (MIE) is the minimum energy required to ignite a dust cloud. MIE is an important factor for dust explosion safety, as it is used to evaluate the potential for a dust explosion and identify the most effective ignition prevention methods. MIE can be measured through a variety of test methods and is important for understanding the flammability of a dust.
MEC stands for ‘Minimum Explosive Concentration’. This relates to the smallest amount of dust in the air that can ignite to cause an explosion.
What is MESG?
The ‘Maximum Experimental Safety Gap‘ is a standardized measurement of how easily a gas flame passes through a narrow opening bounded by heat-absorbing metal. The MESG classifies flammable gases for the design or selection of electrical equipment or flame arresters in hazardous areas. Examples of flammable gases are Acetyleen, Hydrogen, Ethylene and Propane.
What is TLayer?
The Layer Thickness (TLayer) is the thickness of the dust layer that is necessary for a dust explosion to occur. TLayer is an important parameter for dust explosion safety, as it is used to evaluate the potential for a dust explosion and identify the most effective mitigation strategies. TLayer can be determined through testing or through mathematical models.
What is T5mm?
T5mm is the minimum temperature at which a dust cloud will ignite. T5mm is an important parameter for dust explosion safety, as it can be used to evaluate the potential for a dust explosion and identify the most effective ignition prevention methods. T5mm is typically determined through testing or through mathematical models.
What is Pred?
Reduced Pressure, or ‘Pred’ is the maximum rate of pressure rise that can be produced by a dust explosion. Pred is an important parameter for dust explosion safety, as it can be used to evaluate the potential for a dust explosion and identify the most effective suppression methods. Pred is typically determined through testing or through mathematical models.
How to Reduce Industrial Dust Explosions effects
To reduce the risk of a dust explosion, industrial manufacturers must understand the causes, flammability of dust, and the codes and standards that apply. This includes following actions
- safe work practices
- installing proper dust extraction, ventilation and suppression systems, tailored to your requirements
- regularly inspecting equipment for potential ignition sources.
By following these guidelines and adhering to the ATEX Directive, manufacturers can reduce the effects of industrial dust explosions. Read more about How to select an effective industrial dedusting system.
Certain dusts are more likely to ignite than others, and understanding the combustibility classification system can help manufacturers identify the type of dust they are dealing with and make informed decisions when it comes to dust explosion safety. By understanding the causes of dust explosions and taking appropriate steps to reduce the risk of a dust explosion, industrial manufacturers can ensure their premises are safe and their staff are protected.
Finding the best possible solutions leading to minimal effects of dust explosions
With the right equipment and a balanced extraction system, tailored to your sites requirements, you will be able to safely operate protecting people and assets. Reduced operator exposure and safety compliance should be on top of the priority list of every manufacturer.
Next to explosion safety, there are many other reasons for giving priority to effective dust handling. Next to a healthy work environment, effective dust extraction leads to less complaints and rejection as well.
In 25 years, JOA Air Solutions has become the most trusted partner in Explosion Safety for the largest manufacturers worldwide with the most complex processes. Our solutions include:
- Source Elimination: Prevention of combustible dust build-up
- Reduced Explosion Zoning
- Housekeeping Solutions: Central Vacuum Cleaning Systems
- Source Extraction
- Industrial Dust Filters
By choosing JOA, you will be ensured of a clear data-driven approach, reduced operational expenses and predictable results with process guarantees.
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