Several industrial processes are known to generate large amounts of dust. Some of these dust are usually combustible. They can burn or explode if the particles are the right size and in the right concentration.
Dust from solid organic materials (such as sugar, flour, grain, wood, soup powder, spices, flavouring), metals (Fine dust of Aluminium, Magnesium, Titanium, Chromium, Iron) and some nonmetallic inorganic materials normally collect on surfaces such as rafters, roofs, suspended ceilings, ducts, crevices, dust and other equipment.
When the dust is disturbed, there is a high risk of a serious fire or explosion.
What is combustible dust?
A combustible dust is “a combustible particulate solid that presents a fire or deflagration hazard when suspended in air or some other oxidizing medium over a range of concentrations, regardless of particle size or shape.”
According to the US National Fire and Protection Association (NFPA), combustible particulate having an effective diameter of 420 μm or smaller, are considered to be combustible dusts. ATEX use 500 μm as limit.
Such particulate substances have the potential to explode and burn rapidly when the five basic conditions of dust explosion are available. These include:
● Fuel - to burn combustible dust;
● Dispersion - high concentration of fine airborne combustible dust;
● Oxygen - to sustain the fire;
● Confinement - within an enclosed space or structure;
● Ignition - source of heat. For example, hot surfaces such as overheated bearings and other moving parts.
What industries have high risk of combustible dust explosion?
Industries that produce dust as a by-product of their manufacturing processes run the risk of combustible dust fires or explosions. Combustible dust fires and explosions can cause serious damage to property and loss of human life.
The following industries are at higher risk.
● Chemical industry
● Power stations
● Waste management companies
● Gas supplying companies
● Wood Processing Industry
● Coating Company
● Metal industry
● The food and feed industry
● Pharmaceutical Industry
● Recovery Management
● Aerospace Industry
How to determine the level of risk in your manufacturing facility
Conducting a risk assessment of your industrial facility from time to time is sure way to determine your level of risk. A risk assessment is the process of evaluating the probability and degree of potential combustible dust explosion.
The assessment will help industries to determine sources of dust and areas of accumulation.
By doing so, industries can prioritise dust control and avoid future fires and explosions. They can also determine which products and solutions are most suitable for their needs.
Product and solutions for dealing with combustible dust
Envirox provides a wide range of dust collection products and solutions to assist manufacturing companies in capturing combustible dust.
1. Dust Collectors
Our combustible dust collectors are used to capture and filter dry dust and fumes; dry powder and dust with explosion risk applications; light, medium and heavy dust particles, metal grinding and wood dust, among others.
Popular among them are the FMCZ, NFKZ and AUTO-MZ dust collectors.
The FMCZ, also referred to as the FMC cartridge dust collector, was designed to capture and filter dry dust and fumes. Its range of reverse jet cartridge filters is tailored for continuous operation in industrial process filtration and dust collection applications.
The Nederman NFKZ, also known as the NFKZ3000 baghouse dust collector is a modular filter best suited for handling large volumes of air with heavy material contamination levels. They are suitable for outdoor use and ideal for wood waste, combustible dust and extraction of dust and particles.
The Nederman AUTO-MZ, is a powerful free-standing filter with an automatic shaker cleaning mechanism that is suitable for non - continuous duty across various industrial and commercial applications that generate light to medium volumes of dry dust. They are ATEX-certified for explosive dust categories St1, St2 and St3.
2. Extraction arms for at-source extraction:
Envirox’s extraction arms are effective means of getting rid of combustible dust at source, even before they get into the atmosphere. They are highly flexible and extremely simple to position, extend and retract.
Our NEXD combustible dust extractor is designed for applications requiring hygienic dust collection. They are ideal for applications in the pharmaceutical, food process and chemical industries where large amounts of dust need to be extracted at the source.
Additionally, our NEX DX dust and gas extractor arm is ATEX-approved to provide an efficient, responsive extraction of explosive dust. They are ideal for applications in the oil and gas industries.
3. Explosion Isolation Valve:
Envirox’s CARZ explosion isolation valve is designed to prevent the transmission of dangerous effects of explosion pressure wave and flames from a downstream equipment (e.g. dust collector) to upstream areas.
It is an add-on to a comprehensive dust collection solution that will act as a barrier against approaching flame front.