Explosive dusts - Safe and reliable handling
There is a real danger of combustible dust explosions in many factories and processing plants which can be a serious risk for employees, processes and the entire facility. But dust explosions do not occur by accident, it is the interaction of dust particles, their dispersion mixed with oxygen and the confinement of it inside the body of a dust collector. As soon as a specific dust density is achieved below certain particulate dimensions, an explosive environment is produced and a small spark or static electricity can be the ignition source to release an explosion.
As a full-service provider with over 85 years’ experience in the industry, Camfil APC not only sells dust collectors, we always provide our expertise to offer the safest, most reliable and efficient extraction solution tailored to our customers needs. This also includes sensitive processes where explosive dusts are generated and have to be handled reliably and safely to avoid any risks. Therefore our range of dry dust extraction systems can be configured with various explosion protection options to secure the dust collector itself and the infrastructure around it. All Camfil dust collectors with explosion protection are developed in compliance with the latest ATEX standards.
Explosion Protection Options
Explosion Isolation Valve
An explosion isolation valve is designed to prevent a deflagration (explosion) that could occur in the dust collector from traveling back down the inlet pipe protecting the workspace and process equipment/personnel.
Designed to be the “weak” link of the vessel, explosion vents open when predetermined pressures are reached inside the dust collector allowing the overpressure and flame fronts to exit to a safe area. Explosion vents minimize damage to the dust collector caused by overpressure created by a deflagration. Camfil APC’s standard explosion vents are ATEX certified.
Designed to install over a standard explosion vent, the “FlameQuench FQ” extinguishes the flame front exiting the vented area not allowing it to exit the device. This allows conventional venting to be accomplished indoors where it could otherwise endanger personnel and/or ignite secondary explosions.
Second stage HEPA filter
The Gold Series® dust & fume collectors could be optionally equipped with a second stage HEPA filter. This secondary filter prevents collected dust from re-entering the workspace if there should be a leak in the primary Gold Cone filters. Sparks or debris always has potential for being pulled into the collector during operation. The HEPA filter is monitored for changes in differential pressure and can be programmed to signal an alarm or shut the dust collector down, if necessary.
The HEPA filters have been proven to isolate the downstream equipment from the progression of a flame front during an explosion. Gold Series dust & fume collectors with an integrated second stage HEPA filter allow you to recirculate exhaust air back into the work space when your dust is explosive. In some cases, additional pressure wave protection could be required.
To determine the right explosion potection option for your dust collector call our experts - we will be happy to advise you!
About Explosion Protection
What is a dust explosion:
- When a combustible substance is dispersed as a fine dust and the surface exposed to air is increased 1000’s of times.
- If the dust is ignited, it will burn at a very high speed due to the large contact surface with the air.
- This high combustion velocity will release a lot of energy that generates a rapid increase of temperature and pressure. Shock waves are formed.
- The finer the dust, the more violent reaction is generated.
Consequences of an explosion:
- Shock waves of a dust explosion can destroy equipment, parts of buildings and other structures.
- Often operators and other staff are injured or killed during dust explosions.
- There´s always a risk that explosions spread to other buildings or parts of systems, causing further damage.
- During an explosion you often have flying debris, glass, metal parts and stone which can hurt people near to or cause damage on buildings and machinery.
- Also a dust explosion causes high temperatures and fire risk.
Typical explosive dusts:
- Organic dust from food industry, such as baking powder, sugar, tea, coffee, spices and flavourings.
- Synthetic organic dusts such as dust generated from grinding plastic, powder paint and detergent.
- Fine metal dusts like aluminium, titanium, magnesium and chromium. In special cases fine un-oxidised powder from any metal. Even iron powder can explode.
- Pharmaceutical dusts are mostly explosive. Some are hybrid mixed containing both dust and explosive gases.
How do I know if my dust is explosive?
- As a result of EU guideline ATEX 137, system operators of machines at risk of explosion are required to determine and evaluate the risk of explosion by filling out an explosion protection document. To fulfill this requirement it is frequently necessary to determine explosive dust parameters, among other issues, for the suitable design of dust collection systems. Camfil APC is capable of providing the necessary support for the evaluation of the explosion hazard, the detection of the explosive parameters and establishing the recommended explosion protection measures.
- If you are uncertain about the properties of your dust we can also provide you with a dust sample testing in laboratory. Therefore a dust sample is needed which has to be representative of the process being evaluated.
Choosing the right solution for explosion protection on your dust collector, the following factors have to be taken into consideration:
- Does the dust generate within my applications has any explosive properties?
- What kind of dust do we handle - organic or metal type dust?
- Is the dust we handle harmful to worker or the environment?
- Where is my dust collector equipment located, inside or outside?
- Do we want to return the cleaned air back into the building?
The 3 main directives:
- 2014/34/EU (94/9/EC) – ATEX 100: Equipment and Protective Systems for Use in Potentially Explosive Atmospheres. This is applicable to, for example dust collectors.
- 1999/92/EC – ATEX 137: Covering work place safety, risk zones and protection.
- 2006/42/EC The Machinery Directive: Is applicable for machines NOT covered in the 94/9/EC directive. “Machinery must be designed and constructed in such a way as to avoid any risk of explosion posed by the machinery itself or by gases, liquids, dust, vapours or other substances produced or used by the machinery.”
- European Agency for Safety and Health at Work - Guidelines to Directive 2014/34 EU (ATEX) - Safety and health at work - EU-OSHA (europa.eu)
- HSE - Health and Safety Executive - ATEX and Eplosive Atmospheres
- HSE - Health and Safety Executive - Dangerous Substances and Explosive Atmospheres