Dust Control & COSHH

COSHH is the law that requires employers to control substances that are hazardous to health.

The objective of COSHH is to prevent or to adequately control exposure to substances hazardous to health‚ to prevent ill health. This can be achieved by:

Using control equipment‚ eg total enclosure‚ or containment‚ or partial enclosure combined with ventilation systems.
Controlling procedures‚ eg ways of working‚ supervision and training to reduce exposure‚ maintenance‚ examination and testing of control measures;
Worker behaviour‚ making sure employees follow the control measures.
Changing how often a task is undertaken‚ or when‚ or reducing the number of employees nearby‚ can all make an improvement to exposure control.

Most materials‚ when handled in bulk‚ produce dust and control of this fugitive dust is an important aspect of COSHH.

SSL can provide assistance with COSHH compliance and LEV specification or design to achieve the required Workplace Exposure Levels (WEL).

Workplace exposure limits

Exposure to a substance is defined by COSHH as uptake into the body. The exposure routes are:

By breathing fume‚ dust‚ gas or mist.
By skin contact.
By injection into the skin.
By swallowing.

Exposure should be maintained below the WEL by monitoring. Monitoring‚ in the context of COSHH‚ means measuring to show that control is adequate and not the state of a worker’s health. Monitoring is appropriate:

When you need to show compliance with a WEL (Workplace Exposure Limit)
When you need to show that control equipment or personal protective equipment is working well enough

SSL can arrange for a suitably qualified consultant to carry out this monitoring and then help interpret the results into necessary control measures and improvements in control equipment‚ procedures‚ worker behaviour and even reassessment of the workers tasks.

LEV assessment and trouble–shooting

LEV systems are typically used in conjunction with partial enclosure to prevent fugitive dust.

SSL can assess the performance of existing bulk materials handling systems and help identify improvements to either the containment or LEV system to achieve the required Workplace Exposure Limit.

LEV upgrades for COSHH ‘ALARP’ compliance (As Low As Reasonably Practicable)

Work place exposure limits can change‚ typically as a result of a better understanding of the harmful aspects of a particular dust. Hardwood dust has been classified as a carcinogen for some time‚ but only recently has softwood dust been classified as an asthmagen.

This requires WEL’s As Low As Reasonably Practical (ALARP)‚ suggesting improvements to dust control systems are likely to be needed.

SSL can assess the performance of existing LEV systems and provide guidance to improve containment and uprate LEV systems to achieve these lower WEL’s.

Belt conveyor chute and transfer point design

Belt conveyors are commonly used for handling bulk materials over long distances or at high rates. These conveyors can present a particular challenge for good dust control‚ particularly at transfer points. SSL has extensive experience of engineering or re–engineering transfer points and designing LEV systems to control dust at these difficult locations.

Managing the conflict with DSEAR

Compliance with COSHH will tend to drive towards improved or even complete containment. This can cause an apparent conflict with DSEAR (Dangerous Substances and Explosive Atmospheres Regulations) in that the risk on a dust explosion or undetected fire tends to increase as containment is improved.

Hazard zones can be increased rather than decreased and mechanical and electrical equipment may no longer have the appropriate Atex EPL (Equipment Protection Level)

SSL is able to advise on both COSHH and DSEAR and optimise solutions to mitigate both exposure risks and fire or explosion risks.