LEV: dust capture at fixed drum and disc sanding machines

• Introduction
• Drum sanders
• Disc sanders
• Reading list and references
• Further information

Introduction

This Information Sheet is one of a series prepared by HSE's Woodworking National Interest Group. General information on the hazards and precautions for wood dust can be found in Wood Dust: hazards and precautions¹. For general guidance on the principles of design of local exhaust ventilation systems see LEV: general principles of system design³. This Information Sheet gives specific guidance for the design of local exhaust ventilation systems (LEV) fitted to fixed position drum and disc sanding machines, and is relevant to machine designers and users and the designers, installers and users of local exhaust ventilation systems.

Problems with dust control arise from the movement of the sanding head which produces air currents which are often strong enough to counteract the exhaust ventilation system. Dust can also be held onto the abrasive paper by the build up of static electricity, and anti-static abrasives can be purchased to overcome this problem.

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Drum sanders

These machines consist of a rotating drum covered with an abrasive material at which sanding is carried out. The abrasive drum is sometimes replaced by a brush. Captor hoods positioned behind the drum can be inefficient if they are not positioned close enough to the sanding operation. Figure 1(a) shows a captor hood which more fully encloses the sanding drum, giving more effective control. Flanged inlet openings will considerably improve extraction efficiency (see Figure 1(b)).

Figure 1 Exhaust hoods for drum/bobbin sanders

Where larger workpieces are sanded or where heavy duty sanding is required, it may be necessary to enclose the machine in a suitable exhaust ventilated booth.

Exhaust ventilated booth

Where such a booth is used it is important to ensure that the air flow characteristics are such that the dust is effectively drawn into the booth. This can be checked with the aid of a smoke tube generator or dust lamp⁵. For normal amounts of dust, a minimum face velocity of 0.5 m/s will be sufficient but where large volumes of heavy dust are produced a face velocity in excess of 1 m/s may be required.

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Disc sanders

The traditional exhaust ventilation system fitted to these machines is an annular exhaust hood surrounding the disc. This system is not always effective, particularly when sanding takes place on the up-running side of the disc and when larger workpieces are removed from the disc. Dust control can be improved by the use of modified hoods as shown in Figure 2. The greater the degree of enclosure of the workpiece, the better the control will be. Extraction through the worktable will also give considerably improved performance.

Figure 2 Methods of improving exhaust ventilation at disc sanders

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Reading list and references

• Wood dust: hazards and precautions Information Sheet Woodworking Sheet No 1 1990
• An introduction to local exhaust ventilation HS(G)37 HSE 1993 ISBN 0 7176 0456 X
• LEV: general principles of system design Information Sheet Woodworking Sheet No 23 1992
• Control of substances hazardous to health and control of carcinogenic substances. Control of Substances Hazardous to Health Regulations 1988. Approved Code of Practice 4th ed L5 HSE 1993 ISBN 0 7176 0427 6
• Assessment and control of wood dust: use of a dust lamp Information Sheet Woodworking Sheet No 12 1991

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Further information

Further copies of this and other information sheets may be obtained from the Woodworking National Interest Group, Health and Safety Executive, 14 Cardiff Road, Luton LU1 1PP (Tel: 01582 34121)

HSE priced and free publications are available by mail order from: HSE Books, PO Box 1999, Sudbury, Suffolk CO10 6FS (Tel: 01787 881165 or Fax: 01787 313995).

HSE priced publications are also available from all good booksellers.

Other enquiries should be directed to HSE's Information Centre, Broad Lane, Sheffield S3 7HQ Fax: 0114 289 2333

This publication may be freely reproduced, except for advertising, endorsement or sale purposes. The information it contains is current at 9/94. Please acknowledge the source as HSE.

Printed in the UK for the Health and Safety Executive NIS/08/26 C70 9/94