Sedgwick SM210, Operation And Maintenance Instructions

Page: 23 / 29

SM210 Operation/Maintenance Instructions Page 23 of 29
9.3 Noise
Noise levels can vary widely from machine to machine depending on conditions of use.
Persons exposed to high noise levels, even for a short time, may experience temporary
partial hearing loss and continuous exposure to high levels can result in permanent hearing
damage. The Woodworking Machines Regulations require employers to take reasonably
practicable measures to reduce noise levels where any person is likely to be exposed to a
continuous equivalent noise level of 90 dB(A) or more over an 8 hour working day.
Additionally, suitable ear protectors must be provided, maintained, and worn.
Machines identified as generating unhealthy noise levels should be appropriately marked
with a warning of the need to wear hearing protection and it may be necessary to
designate areas
of the workplace as ‘Ear Protection Zones’. Suitable warning signs ar e
specified in the Safety Signs Regulations Act 1995. It may be necessary to construct a suitable
enclosure, for which professional advice should be sought.
Further information and references to practical guidance are contained in free leaflets
available from The Health & Safety Executive.
Using correctly designed extraction hoods and a compatible system the compound effect
on this machine was to increase the readings by 1dB(A).
The following noise levels were recorded at a distance of one metre from the machine
(operator side) using varying feed rates and depths of cut.
TIMBER DEPTH OF CUT NOISE LEVEL dB(A) @ 1M
None No load 72
Softwood 38mm 85
Softwood 50mm 85
Hardwood 63mm 85
The figures quoted for noise are emission levels and not necessarily safe working levels. Whilst
there is a correlation between emission levels and exposure levels, this cannot be used
reliably to determine whether further precautions are required. Factors that influence the
actual level of exposure to the work force include the duration of exposure, the
characteristics of the workroom, the other sources of dust and noise, etc., i.e. the number of
machines and other adjacent processes. Also, the permissible exposure levels can vary from
country to country. This information, however, will enable the user of the machine to make a
better evaluation of the hazard and risk.
The list below outlines some of the variables which directly affect the noise level of the
machines:
VARIABLE
RELEVANT FACTOR EFFECT
Timber
Species Hard stiff timber can mean more noise
(approx. 2dB(A) difference when cutting
oak and pine) & more transmitted noise.
Width Wide work pieces radiate noise over a
greater area increasing the noise level.
Thickness Thin workpieces generally vibrate more
increasing the noise level.
Length Long workpieces transmit noise away
from the cutting area towards the
operator.
Tooling
Width of Blade This affects the windage noise and
increases roughly in proportion to the