Introduction to Health and Safety at Work

11.16 
Guard construction
The design and construction of guards must be appro-
priate to the risks identifi ed and the mode of operation 
of the machinery in question.
The following factors should be considered:
➤
strength – guards should be adequate for the pur-
pose, able to resist the forces and vibration involved, 
and able to withstand impact (where applicable)
➤
weight and size – in relation to the need to remove 
and replace the guard during maintenance
➤
compatibility with materials being processed and 
lubricants etc.
➤
hygiene and the need to comply with food safety 
regulations
➤
visibility – it may be necessary to see through the 
guard for both operational and safety reasons
➤
noise attenuation – guards can often be used to 
reduce the noise levels produced by a machine. 
Conversely the resonance of large undamped panels 
may exacerbate the noise problem
➤
enabling a free fl ow of air – where necessary (e.g. 
for ventilation)
➤
avoidance of additional hazards – for example, free 
of sharp edges
➤
ease of maintenance and cleanliness
➤
openings – the size of openings and their distance 
from the dangerous parts should not allow anyone 
to be able to reach into a danger zone. These values 
can be determined by experiment or by reference 
to standard tables. If doing so by experiment, it is 
essential that the machine is fi rst stopped and made 
safe (e.g. by isolation). The detailed information on 
openings is contained in EN 294:1992, EN 349:1993 
and EN 811:1997.
11.17 
Practice NEBOSH questions for 
Chapter 11
1. 
List
the main requirements of the Provision and Use 
of Work Equipment Regulations 1998.
2. (a)