Types of wood dust
In addition to the tiny particles of wood produced during processing, wood dust can also contain bacteria and fungal and moss spores. The quantity and type of wood dust will depend on the wood being cut and the machine you are using, for example:
whether the timber is green or seasoned
whether it is a hardwood, softwood or composite board
how aggressive the machine cutter or blade profile is
The biggest risk is from fine dust, as you can breathe this deep into your lungs where it will do the most damage. Fine dust will also spread further from the cutting process so it is important to clean ledges and other workroom surfaces regularly to prevent dust accumulating.
Why is it necessary to control wood dust?
Wood dust is a substance hazardous to health because it can cause serious non-reversible health problems, including:
obstruction in the nose, and rhinitis
a rare type of nasal cancer
Wood dust is flammable and, in certain situations, can cause a fire or explosion. Every year, premises are severely damaged or destroyed by wood dust fires that usually start in dust extraction equipment. Wood dust explosions in buildings are rare, except in the chipboard industry.
It also makes sense to control wood dust from a business point of view as you will need less time for clearing up, and there will be fewer slips and trips hazards caused by settled dust.
What causes high wood dust exposures?
The following activities are likely to produce high dust exposures, some over long periods:
machining operations, particularly sawing, routing and turning
sanding, by machine and by hand
using compressed airlines to blow dust off furniture and other articles (to be avoided) before spraying
hand assembly of machined or sanded components
operations involving processing composite boards, eg medium-density fibreboard (MDF)
the bagging of dust from dust extraction systems
housekeeping, especially if sweeping up and using compressed airlines (again to be avoided)
What the law says
Because of the potential health problems, wood dust is covered by the Control of Substances Hazardous to Health Regulations (COSHH). These set out the legal requirements to protect workers from health risks arising from hazardous substances at work. Under COSHH, employers (including contractors) have a duty to carry out a suitable and sufficient risk assessment and take steps to ensure they prevent or adequately control exposure.
COSHH states that, where it is not reasonably practicable to prevent exposure to a hazardous substance, control of that exposure should only be treated as adequate if:
the principles of good practice for the control of exposure are applied. This is set out in Schedule 2A to the COSHH Regulations and includes the requirement to provide suitable personal protective equipment, such as respiratory protective equipment (RPE), combined with your other control measures, such as LEV, if adequate control cannot be achieved.
any workplace exposure limit (WEL) is not exceeded. The WEL for hardwood dust is 3mg/ m3 (based on an 8-hour time-weighted average). The WEL for softwood dust is 5mg/m3 (based on an 8-hour time-weighted average). For mixtures of hardwood and softwood dusts the WEL for hardwood dust of 3mg/m3 applies to all wood dusts present in that mixture.
for a substance that has the potential to cause cancer or occupational asthma (such as wood dust) exposure is reduced to as low a level as is reasonably practicable (ALARP). This means that, even if your control measures (eg LEV) reduce exposure to below the WEL, but there remain improvements that could further reduce the exposure, then you should make these improvements if reasonable and practicable.
How do I control wood dust exposure?
The best way for you to do this is to use fixed LEV that will effectively control the dust at source as it is produced. In some cases, the hood(s) used to capture the dust can be part of the machine housing or guards.
Fine wood dust becomes suspended in air and capturing the dust is all about controlling the movement of this dusty air. This can be difficult as the high-speed rotating blades and cutters of woodworking machines act like fans and generate strong air movements.
The job of the LEV system is to contain this air movement and with it the dust. Many LEV designs fail to do this because the hood design is wrong. Hoods should be designed to contain, receive and control these air movements.
What Can RCS Do For You
RCS are acutely aware of the detrimental effects of installing an ineffective LEV system. Our fully qualified LEV engineers will provide an LEV system, designed to your specific needs and installed correctly. In addition, RCS can carry out regular maintenance and COSHH testing of your LEV systems to ensure that you remain fully COSHH compliant.
RCS's engineers will endeavour to provide you with the most effective and cost-efficient solution for wood dust extraction and filtration in partnership with Donaldson. Call us on +44(0)1563 546807 or click here to contact us for more information.