Employers are required by the Control of Substances Hazardous to Health (COSHH) Regulations to implement effective and reliable control measures that reduce dust exposure. This is especially important in workplaces where dust is prevalent, such as construction sites, and those that create dust that is particularly dangerous, such as silica dust or wood dust.
In this article, we will explore the hierarchy of control and some of the control methods an employer can use to reduce exposure to dust.
Shown below are several control measures in order of reliability, which is a useful way of establishing which of them should be considered first:
The most effective control measure, and the first thing that should be considered, is whether a material that emits harmful dust can be eliminated and replaced with a safer one. This could be a material that produces fewer dust particles and/or a dust that causes less harm.
For example, powdered alumina is often used as a replacement for flint and quartz in the pottery industry. While the use of alumina still poses a risk to workers, it is significantly lower than that of flint and quartz, which can release respirable crystalline silica when cut.
If it is not possible to replace the material, the next thing to consider is whether it can be used in a safer form, such as in pellet, emulsion or paste form. This will prevent dust from being spread when the material is processed, stored, mixed, etc.
An employer should also consider whether the process can be changed to reduce the amount of dust that is emitted. For example, using special cutting techniques to cut materials instead of grinding or sawing can reduce dust emission, as can damping down materials before they are processed.
Engineering controls are an effective way of reducing dust exposure, but because they require regular maintenance to remain effective, they are unlikely to be as reliable as the measures discussed previously. The three main types of engineering control used to reduce dust exposure are:
Segregating or totally enclosing certain processes can reduce the number of people who are exposed to the dust they create. To be effective, the processes that take place in these segregated areas should be machine operated or controllable remotely.
Alongside this, materials that are not in use should be stored in enclosed areas and/or behind windbreaks to prevent them from spreading dust and being affected by wind erosion.
Local exhaust ventilation (LEV) is a system that extracts and filters dust from the air so that it cannot be breathed in. These systems can be stationary, or attached to a tool, and should be positioned as close to the source of the dust as possible to ensure that they are effective.
For more information on LEV, click here to view the relevant HSE guidance.
Wet dust suppression is a dust control technique used with cut-off saws that involves spraying water onto the rotating cutting disk to reduce the dust emitted. It also helps prolong the life of a tool by reducing the amount of dust the motor has to work in.
To be effective, water must be continuously supplied to the cutting disk. This can be done using a portable pressurised bottle system, or by connecting the tool directly to a water main.
Another way that dust exposure can be controlled is to change working practices and apply administrative controls. These may include:
The final dust control measure that should be considered is the use of personal protective equipment (PPE). While it is an effective measure, it should only be used as a last resort because it relies on a person remembering to use it and knowing how to do so correctly.
The specific type of PPE that is used will vary depending on the type of dust present in a workplace, but will usually feature some form of protective clothing and respiratory protective equipment (RPE).
Any PPE required should be supplied by the employer. They should also provide facilities in which workers can store and change into/out of PPE.
Protective clothing is clothing worn to prevent the contamination of a person's skin, hair or personal clothing. It should be kept separate from their personal clothing and remain at work where possible to prevent contaminants from spreading.
Employers should also make arrangements to regularly launder protective clothing stored in the workplace.
Respiratory protective equipment (RPE) is a form of personal protective equipment designed to protect the wearer from breathing in harmful substances, including dust. There are two main types of RPE:
RPE must be selected carefully and be appropriate for the worker, the task being carried out, and the environment in which it will be used. For more information on RPE, click here to view the relevant HSE guidance.
To make sure that these control measures are effective, all employees who work with dust should receive sufficient instruction and training. This includes those that do not work directly with dust-producing materials, such as cleaning and maintenance staff. Specifically, employers should ensure that their staff:
At Commodious, we offer a Dust Awareness course that explores what dust is, outlines which dusts are most dangerous, and explains what workplaces can do to prevent or limit dust exposure.