Blog / How does a dust collection system work?
1 DECEMBER 2022
In its most basic form, LEV (Local Exhaust Ventilation) systems are industrial dust extraction systems designed to draw airborne dust particulate away from production areas to improve the air quality in a production facility. The dust extraction system reduces exposure to harmful inhalable fumes and dusts and helps comply with safety standards. Once airborne dust is captured and conveyed to a dust extraction filter unit, it is purified by being separated from the airstream. The air is then released back into the building or discharged externally to atmosphere.
It is essential to control the level of respirable dust inside a production facility to prevent health hazards for your employees, and it should be regarded as a priority. This article will dive into your LEV system's key components and considerations.
The workplace exposure limits (WEL) for various types of products are specified in a document called EH40 and can be downloaded for free on the HSE's website. Generally speaking, the WEL level of dust permitted within a workspace range from 4 mg/m3 to 10 mg/m3 based on an eight-hour working shift. However, some dusts have lower WEL exposure levels as they are considered more harmful to health than others (to learn more about dust limits, click here). As we know, dust is created from an assortment of materials but is typically divided into respirable and inhalable dust.
Respirable dust particles are generally much finer and are often not visible to the naked eye. They penetrate further into the body and present a far higher health risk. Certain dusts present a particularly high risk. For example, breathing in only a very small amount of respirable crystalline silica particles can cause multiple diseases, including silicosis (an incurable lung disease that can lead to disability and can be life-limiting), lung cancer, chronic obstructive pulmonary disease (COPD), and kidney disease. For this reason, the respirable level of crystalline silica acceptable in the workplace is as low as 0.1mg/m3 in EH40.
Single pass dust extraction filter units will always pass a small percentage of dust particulate through them. This is called the outlet emission and different types of self-cleaning single pass filter units have different levels of outlet emissions. Therefore, what needs to be considered is the quality of the required filtered air. This will often depend on whether you are emitting the filtered air back into the building or exhausting outside to atmosphere. Therefore, when discharging back into a production facility the question needs to be asked 'do I need secondary filtration and if so to what level of efficiency?' to ensure that the exposure levels are kept below the WEL levels prescribed in EH40. Even when discharging to atmosphere there are questions to be asked including whether the system needs to comply with the Industrial Emissions Directive (IED) and at what height the filtered air need to be discharged at.
Once you have assessed your ventilation needs and understand your emissions limits, talk with your dust collector or filter unit supplier to find the right technology for your process. The company or manufacturer will be able to help you understand what your application will require in terms of LEV and what it will involve, both in terms of power and compressed air consumption, to achieve emissions control goals in a cost and energy-effective way.
To keep within the exposure and emission limits it is essential to maintain your dust extraction systems to ensure that it runs efficiently and at full capacity. Be sure to stay in contact with your manufacturer/ filter unit supplier for future modifications or expansions to your existing process, as failure to do this often results in an ineffective LEV system. Experienced LEV engineers can ensure your system is balanced and help guide you through any necessary design changes. Contact integratedAIR Filtration today to help you with your dust and fume extraction needs.
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