There are many industries where the production processes obviously give off toxic or harmful fumes, in others these may be less obvious. Simply venting to atmosphere – removing the toxic hazard from the workspace – is not an option. The by-products of the process need to be treated effectively to ensure that any external as well as internal emissions are within the safe limit guidelines and present no hazard to the health of employees or the general public. Safe operation of industrial plant that controls the level of emission of dust and fumes is a benefit to the success of the company and its products. The consequences of not managing these emissions can and has resulted in injury, illness and even death. Employers must comply with the Control of Substances Hazardous to Health Regulations 2002 (COSHH).

These set out eight key steps to take:

All industries must address the issue of dust and fume control, with health and safety legislation as the key driver for control. While fumes can be seen as more hazardous and volatile, dust is present in many industries; correct and safe handling will reduce the risk of a dust explosion. Such events take place in industries as diverse as food production (sugar, flour, custard powder), wood machining, papermaking, organic chemicals, plastics, metal powders and minerals. The consequences of not tackling the problems are potentially huge and will impact the viability of the organisation through the insurability of its facilities and machinery. In the words of the European Agency for Safety and Health at Work, "proper management of dangerous substances protects workers and the environment while ensuring the quality of the products". Indeed, the rewards of implementing effective dust and fume control systems can bring financial as well as health benefits. An example cited by the agency is a UK printing facility which, with little cash spent, saved more than £50,000 a year and halved the levels of solvent vapour in the workplace. In industries where lasers are used to mark or etch information onto products, there is a need to ensure control of dust and fumes. Hazardous dust is created during the marking process, as the lasers cut, etch or engrave the product, which may be plastic, ceramic, glass, wood, rubber and even cardboard. Without effective removal of the dust, the laser lenses may become dirty, the mark itself may not be made accurately, the product may be contaminated, and of course, the employees using the tools may be exposed to harmful dust. In each case, the lack of effective dust extraction can cause production delays, damage to machinery and increases in staff sickness levels – and these may be the least of the problems. An ineffective system can result in compensation claims from employees and non-compliance with COSHH regulations.

Just as varied as the industries that generate dust and fumes are the wide range of types, functions and services from the specialist industries that supply the solutions. Dependent on whether the workplace is a bench, workshop or manufacturing production line, ducted fans, portable appliances, or laminar flow booths may be deployed.

Other important criteria include:

Another good example of the diversity of the installations where dust and fume extraction equipment is put to very effective use is in the processing of the humble potato. Wisbech-based Greenvale Foods installed extraction equipment made by the Air Services Division of Carter Environmental Engineers (CEE), to remove starch and product-laden steam from the production area of its newly upgraded potato processing plant. A division of leading potato supplier Greenvale AP, the company has invested £1.5m to double dehydrated potato flake production capacity to 16,000 tonnes a year. The system was designed and installed by lead contractor Environmental Engineering UK, including fanset, ductwork and noise attenuation. It provides extraction of starch-laden steam from the cooking and dehydration processes, with cleaned air and steam vented to atmosphere. Following cooking and dehydration, the product is ground to a specified particle size for use in the snack food industry. Combining multi-stage cleaning in a single unit, the Cyclovent typically requires 25% less energy for the same efficiency than conventional single-stage venturi scrubbers. Alternatively, it will achieve significantly greater collection efficiency than a conventional unit operating at the same pressure loss. The simple Cyclovent design does not require expensive specialist components or control equipment. It is effectively self-cleaning and is particularly suitable for problematic sticky gas streams. The range of industrial processes gives rise to a large number of potential solutions, but which one is right for your process? How can you provide a costeffective solution?

The approach advised under COSHH regulations is to remove or reduce the exposure to acceptable levels. A first consideration is to change the process or activity so that the hazard is no longer generated; replace it with a safer process or use the hazardous material in a safer form. An example of a such change in process is a case, referred to by European Agency for Safety and Health at Work, where a manufacturer of arc welding systems replaced high-solid painting by powder coating. A powder booth and an environmental room were installed, reducing employee exposure to organic solvents, and improvements in the control of dust emissions. On top of this, it was found that powder coating produced greater resistance to corrosion and a better finish. In metal treatment industries – such as cutting, machining, or profiling – some machinery comes with extraction equipment already fitted, but occasionally only around the working area, and within the confines of the equipment.

Extracting dust in particular requires attention to be paid to ensuring the volume of air and its velocity, and interconnecting pipework and fans, adequately meet the need to collect and remove the dust from the workspace. Consider the example of fume extractor arms used in a welding process. Under normal welding operations, the recommended airflow at the working area is 800 m3/hour. Achieving this where multiple workspaces, and consequently multiple extraction points, are concerned depends on the correct calculation of pressure drop, fan size and ducting layout. This type of initial analysis could be applied with equal effect to small workshops, garage repair bays and light industrial premises. When choosing a system, always note that there are hidden operational costs in buying a low-cost installation that initially meets the process need; with very low-cost fume extractors there is a trade-off between performance, filter life and perhaps even safety. For large installations, similar design, planning and installation criteria apply. Selecting the right fan, filter and ducting is critical to the success of the finally installed system, and whether or not the production operations meet required safety regulations. When it comes to maintaining the systems, there are clearly defined criteria for controlling dust and fume extraction processes (some international, and some local), all of which are governed to a degree by the COSHH regulations for LEV (local exhaust ventilation). This advocates weekly inspections for LEV equipment as part of the plant maintenance schedule, but there are also statutory requirements to be fulfilled. For instance, extraction equipment must, in general, be fully examined once every 14 months, with the results recorded. For non-ferrous foundries and processes where metal dust is produced, this interval is six months.

Equipment manufacturers have improved their products in many instances to reduce downtime, and utilised innovative techniques to automate cleaning. Some of these include periodic reversal of airflows to clean filters, and containers, bags or tanks to store the material prior to disposal. Filters are an integral part of dust and fume extraction systems, with pre-filter filters to prevent premature blockage of the main filters, some of which may be HEPA (high-efficiency particulate arresting) filters. These types of filter were originally developed for the nuclear industry, many years ago, and at best can remove up to 99.7% of particulates from the atmosphere. Some designs are a concertina, or pleated arrangement, the general purpose of which is to extend the life of the filters, reducing downtime for filter changing. Vacuum systems may be designed to suit most businesses and processes, whilst in some cases use of fixed rather than portable systems can lower servicing costs, and with the use of automatic valves, additional reductions can be achieved. Overall, the design and installation of any extraction system can be a key factor in determining the most cost-effective business process operation.