It is all too common to find people that view their principal health and safety control measures as being dust masks, safety goggles and hearing protection ie personal protective equipment (PPE).
However, such measures should be regarded as tertiary measures which will need to be adopted only if more permanent options are not applicable.With the main health and safety issues there are well defined hierarchies of control – generally along the lines of those shown in table 1.
Invariably these will start with the elimination of the hazard as the preferred option, followed by a fixed form of control which does not rely on an operator. Controls which rely solely upon operators eg training and PPE, should be seen as last resorts because of their lack of reliability and the fact that they protect only the individual that has been trained/issued with the PPE.
An alternative methodology splits controls into:
Hazardous substance
A good example is provided by wood dust. This is defined as a hazardous substance in accordance with the Control of Substances Hazardous to Health Regulations 1999. It has also been given a maximum exposure limit of 5mg/m³. This level of personal exposure must not be exceeded and employers must take measures to reduce exposure as far as practicable below it.
The ultimate way of ensuring that your employees are not exposed to wood dust is to avoid creating it in the first place. This is unlikely to be practical in the majority of situations within the timber and furniture industries as it would involve purchasing timber which had already been processed to the requirements of your company.
It will be more realistic to look at ways of reducing the amount of dust produced. For example, purchasing timber with specifications most suited to the end product will reduce the amount of processing required. Such minimisation will reduce the amount of dust generated and will also reduce associated labour and processing costs. However, the elimination of dust will only go so far to reducing employees exposure.
No guarantees
The main wood dust control measures used by the sector involve the enclosure of the cutting operation and the removal of the dust through local exhaust ventilation (LEV). Such controls are not guaranteed to meet emission limits – as shown by the Health and Safety Executive‘s Woodworking National Interest Group survey on wood dust. The survey showed that 66% of sites had at least one person being exposed to wood dust levels above the maximum exposure limit (MEL). And, 13% had at least one person exposed to 10 times the MEL!
Therefore, the safe system of work might include requiring the machine operator to check that the extraction is working prior to using the machine. LEV testing should also be conducted at least every 14 months. The operator should be trained on the importance of the extraction equipment and any methods through which this can be optimised, eg the correct placement of the work piece on the machine to optimise dust removal. There should also be requirements regarding the regular vacuuming of the work place (rather than sweeping) to minimise the mobilisation of any dust that has escaped extraction.
Dust masks might be considered to reduce exposure even further. Such PPE is not desirable as a principal method of dust control as it does nothing to remove the hazard and it only protects the wearer. Thus, visitors or those passing through the area without masks will have no protection.
In addition, it is all too common to find that PPE is used when first issued, but is then discarded because of laziness or concerns over comfort. Further problems occur if the PPE is not worn correctly and maintained. Such equipment may also give a false sense of security and can be cumbersome, leading to other problems.
Companies can help to minimise these problems by fulfilling their duties under the Personal Protective Equipment at Work Regulations 1992. These regulations require that employees should be made aware of the risks, the benefits of the PPE, how to use it properly, maintain it, store it and where to obtain it. The HSE wood dust survey showed that only 7.5% of sites had provided training on PPE use.
Lastly, many operators assume that one mask is suitable for all problems. However, a mask designed for filtering out particulates such as wood dust will be useless if worn in a wood coating shop to protect against solvent fumes.
Minimise solvents
The latter area provides another example of a control hierarchy in operation. It is preferable to eliminate as much solvent as possible, eg via a switch to water based coatings. If this is not possible, solvent use should be minimised through the optimisation of transfer efficiencies, use of lids on tins and the collection and containment of solvent-based wastes. This generally makes economic and environmental sense, as well as protecting the health of workers.
Training will form a key part of these reduction programmes, ensuring that operators are aware of the benefits that they will derive personally from solvent minimisation. Depending on the solvent species in use, PPE may need to be worn. For example, gloves should be worn with solvents which can be absorbed through the skin and air fed masks will be needed if isocyanates are sprayed eg in polyurethane coatings.
Ironically, a company switching from the hand spraying of solvent-based coatings to the automated application of ultraviolet cured alternatives will minimise the solvent hazard but introduce new issues associated with machinery.
Engineering controls
When considering the reduction of machinery hazards, engineering controls will again play a key role. Manufacturers should design machines so as to minimise hazards. Machinery buyers also have a duty to ensure that the machines are suitable for their desired use.
Unfortunately, an operator has to work close to the hazardous area of many woodworking machines. If the hazard cannot be completely removed, consideration will switch to the use of fixed guards which provide a permanent enclosure to prevent access to dangerous areas. These guards should be hard to remove, preferably requiring special tools, access to which is controlled.
If fixed guards are not practical, other types are available, eg interlocking systems, automatic guards, trip devices and adjustable guards. Safe systems of work should be developed to ensure that operators check that guards are working correctly and that they do not override or remove them. Supervisors will also need to check that guards are correctly used.
Training and the assessment of competence are important features of any programme to minimise machinery risks. Detailed guidance is provided in the HSE approved code of practice: Safe use of woodworking machinery (L114).
Close parallels
Finally, it is interesting to note the close parallels between health and safety control hierarchies and the waste management hierarchy which is central to environmental management. The latter has waste elimination as the ultimate option, followed by minimisation, reuse, recycling, recovery and finally disposal.
Despite this fact, 70% of the UK’s waste is still disposed of to landfill!
