Functional Safety, further details
HSEC's Functional Safety Advisory Service provides specialist advice for companies who are involved with the
design, manufacture, operation and maintenance of Safety Related Systems.
The services offered have been designed using the guiding principles of BS EN
61508, other related standards and the recently published HSE guidance ‘Managing
competence for Safety Related Systems’.
Safety Related Systems can take many different forms. BS EN 61508 specifically
focuses on Electrical, Electronic, and Programmable Electronic Safety Related
Systems, although safety functions can equally be performed by other technologies,
for example, mechanical, hydraulic or pneumatic systems, or by people.
The consequences of failure of Safety Related Systems are generally most evident
during operation of the equipment under control. However, the causes of failure can
result from random hardware faults or systematic design failures, which could have
been introduced at any stage of the overall safety lifecycle. For example, as some
safety functions are better performed by automatic systems and others are better
performed by people, incorrect safety function allocation may result in a systematic
design failure that when combined with high pressure situations and/or active human
errors may contribute to a serious accident.
The approach detailed by BS EN 61508 addresses the contribution to functional
safety made at all stages of the overall safety lifecycle, from concept through
to decommissioning or disposal. Following from this is a requirement that allocation of safety functions to the different technologies will almost
certainly include the allocation of safety functions to people such as operators
or maintainers.
BS EN 61508 requires a consideration of human factors, but does
not specify how they should be considered. The Health and Safety Executive (HSE)
have recently published guidance on ‘Managing competence for safety-related
systems’. This is concerned with the competence management of persons who have
any involvement with Safety Related Systems. This could refer to involvement
with operation, maintenance, design, review or manufacture.
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