PWE October 2021

A irborne dust and particulate waste from manufacturing processes are progressively unacceptable in today’s facilities when trying to achieve an efficient working environment. If physical concerns over product quality and environmental health are hard enough to achieve, then external pressures from COSHH and ATEX regulations only build on the mounting pressure of having to maintain clean and healthy workplaces. Therefore, the decision to ignore dust in ATEX environments can have severely detrimental repercussions, with one of the worst-case scenarios being an explosion. Dust explosions occur when combustible dust is mixed with air or oxygen and is ignited. For this to happen, the dust must occur in sufficiently large concentrations. Almost all flammable substances that arise due to, or that are used during industrial manufacturing, are combustible and can cause explosions under certain conditions. Examples of such substances include coal, flour, cereals, wood, cotton, and certain plastics. It is important to consider, however, that material does not have to be flammable in normal conditions to become explosive as dust. In fact, it is not just organic material such as flour or wood dust that can pose hazards, but also aluminium, stainless steel, titanium, and certain plastics for example. Created in the manufacturing process, these inorganic dusts can be extremely dangerous in the right/ wrong circumstances. The association between dust and explosions isn’t exactly well documented either. Fuels, wood and solvents, for example, are universally known for the dangers they pose if exposed to certain conditions. Everyone knows to put sufficient procedures in place if handling clearly explosive materials – you wouldn’t wave an open flame near a can of petrol, for instance. With dust though, the major issue is the fact that most people associate it as merely a household nuisance. This harmless image, however, is one of the biggest challenges when it comes to changing people’s perceptions. The explosive nature of dust lies in its large surface area. With gases and liquids, both only burn at the surface when the substance reacts with oxygen. It’s a common misconception that despite its relative size, dust has an extremely large surface area, too. A large spherical object would have a surface area limited to its size. However, if this spherical object were then broken down into dust particles, the surface area would be multiplied many times over. This much larger surface area combined with the small mass of a dust particle, means that the substance burns extremely quickly and with minimal energy required. When in a confined space, with dust suspended in the air, this explosive mix can even be strong enough to demolish buildings and pose a serious threat to the health of anyone nearby. Another major risk posed by dust is that of secondary explosions, which is where an initial blast disturbs accumulated dust in a plant, forcing it into the air, igniting it, and creating a more potent explosion. It is this risk, though, that often leads to greater damage as secondary dust explosions can tear through buildings with ease. So, how can the accumulation of dust and particulate waste be prevented in ATEX environments? Whilst it may seem that air cleaning through large-scale ventilation is a primary option, many businesses could significantly improve their facilities through on-tool extraction directly at the source of the problem. This involves the utilisation of high vac systems to transport the waste to a centralised location for easy disposal or to intermediate pre-separators for potential recycling. A major benefit of a good high vac system is that it can also be used for general clean up as an ‘in-house’ vacuum, negating the need for both sweeping (which creates an enormous amount of hazardous airborne dust in itself) and mobile vacuums. Whilst mobile units can work in certain situations, they can easily fall foul of poor maintenance, are often fitted with unsuitable filtration quality, and can cause trip hazards or manual handling issues. With COSHH stating that the primary method of dust removal should be at its source and the fact that a proper in-house cleaning schedule could reduce or eliminate the requirement for ATEX zoning, it is no wonder, then, that leading companies in many industries are now implementing high vac solutions. Typical industry sectors using high vac systems include aircraft manufacturers, automotive manufacturers, body shop repair firms, wind turbine manufacturers, pharmaceutical companies, electronics manufacturers, and the food industry. People are realising that, rather than being a capital cost problem, an integrated dust extraction system can benefit and support their business to move forward unhindered through the reduction of health, working practice and quality issues. A clean work environment and healthy staff will reap benefits of reduced sickness costs and project a better profile to customers. *James Miller is the director of Dustcontrol UK For further information please visit: https://dustcontroluk.co.uk/ 34 | Plant & Works Engineering www.pwemag.co.uk October 2021 Handling & Safety Matters Focus on: Dust & Fume Extraction Today’s strenuous workloads and taxing pressures to produce high-quality products are generating an increased demand for cleaner production facilities, though, the intensity seems to make this need harder to attain than ever before. James Miller* reports. How to maintain a healthy and efficient workplace in ATEX environments