Many items may not seem combustible, but often are extremely flammable and dangerous when they are ground into dust. Not knowing if the dust in your workshop is combustible or not, is dangerous as unexpected accidents and explosions can occur. Should a combustible dust in the air come into contact with a flammable source and ignite, this ignition will spread to the remaining dust in the air and dust resting on equipment causing a dangerous explosion, possibly resulting in loss of life, injury and extensive damage to property.
To determine if your dust is combustible, a lab test needs to be done. When dust is evaluated for combustibility the two values that are taken into account are the Kst value, which measures the relative severity of an explosion should the dust combust, and the Pmax value which indicates the maximum pressure that would be created if the dust were to explode. The Kst value is determined using the shape, size and moisture level of the dust particles when determining its result. A sample of this dust is ignited in a controlled environment and then measured and analysed.
Once the dust has been analysed it will be given an *St classification, starting at 0 (no explosion) and ending at 3 (very strong explosion). The Kst value will determine this classification, with a high Kst value registering on the higher side of the St scale.
The eradication of this dust using a dust collector is necessary to ensure that any dust emitted into the air during application is collected and expelled, leaving no dust in the air or on equipment.
Envirox, the supplier of quality Nederman dust collectors, understands the needs when it comes to eliminating dust expelled into the air, and has included in its range of dust collectors, ones suitable for the collection of combustible dust. When purchasing a dust collector to be used with combustible dust, the St classification should be checked.
Included in the Envirox Nederman range of dust collectors, those suitable for the collection of combustible dust includes:
- The Nederman AUTO M-Z, a powerful free-standing filter suitable for non-continuous duty during various industrial and commercial applications that expel light to medium volumes of dry dust. This dust collector is ATEX-certified for explosive dust categories St1, St2, and St3.
- The Nederman MJC Mini Ex, used for light to medium volumes of dry dust and developed for continuous use in industrial process filtration and dust collection applications. It can be used during applications such as conveying, screening, sieving, mixing, bin/silo venting, welding, cutting, and shot, sand and bead blasting. It is also suitable to be used with chemical, plastics and pharmaceutical powders. The MJC Mini Ex is Atex certified for explosive dusts St1, St2 and St3
- The Nederman MCP SmartFilter dust collector, a multi-purpose dust filtration system suitable for applications such as welding, metal cutting and those that expel general dust. It can also be customised to client specifications with up to airflow demands of up to 28 000 m3/h. This dust collector can be used as a standalone unit, or as multi-filter solution and is suitable for both indoor and outdoor usage.
- The Nederman MEP SmartFilter dust collector, suitable for applications such as grinding, shot blasting, metal cutting and general dust collection. It can be used as a standalone unit or as a multi-filter solution and can be located either indoor or outdoor. Its Insight Ready control allows for full system operation including control and monitoring.
- The Nederman LCP dust collector is perfect for corrosive dust applications and includes the option of cartridge media types suitable for most applications. The units have integral pre-separation chambers which increases the dust load capacity and decreases the load on the filter cartridges. It is suitable for continuous use, and includes on-line high, efficiency pulse jet cleaning. It is Atex certified for explosive dusts St1, St2 and St3.
For more information on which dust collector is suitable for your combustible dust collection needs, please contact Envirox. Envirox’s years of expertise will ensure you that you are working with professionals who are able to give you an effective solution.
*For more information on the types of St classifications, and which types of dusts apply, please see below:
- St 0: Kst value 0 – no explosion. Typical of silica dust, welding-generated dust and thermally generated dusts (from cutting processes, for example).
- St 1: Kst value >0-200 – weak explosion. Typical of charcoal, powdered milk, sugar, sulfur, wood dust, zinc.
- St 2: Kst value >200-300 – strong explosion. Typical of cellulose, wood flour, poly methyl acrylate (PMA).
- St 3: Kst value >300 – very strong explosion. Typical of metal dusts such as aluminum, magnesium and titanium.
