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Working
in a safe environment is something many people take for granted
and do not even think about, however for personnel working in
the chemical, pharmaceutical, food processing, utilities and oil
and gas industries, the knowledge that the work environment is
as safe as possible will always be of paramount importance.
Ensuring that standards for safety are being continually
developed therefore remains a priority for these industries
worldwide.
To
members of the Instrumentation, Systems and Automation Society,
functional safety is a prime concern.
Functional
safety is defined by a new international standard as ‘that part of overall safety relating to the equipment under control and
the control system which depends on the correct functioning of
the electric, electronic and programmable electronic (E/E/PES)
safety related systems, other technology safety related systems
and external risk reduction facilities’.
With the increasing use of such systems, the problem of
knowing whether a safety system will work
effectively to prevent a catastrophe is a very real one.
IEC
61508 is an international standard for safety-related systems
which sets out a generic approach for all safety lifecycle
activities for systems comprised of electrical and/or electronic
and/or programmable electronic components that are used to
perform safety functions.
Who
are the members of IEC?
Membership of IEC consists of more than 60 countries, including
all major industrial nations around the globe, and a growing
number of developing countries.
There are two forms of active participation in IEC:
- Full
members are national committees, each having equal voting
rights.
- Associate
members have observer status, and can participate in all IEC
meetings, however they maintain no voting rights.
This
unified approach has been adopted in order that a rational and
consistent technical policy can be developed for all
electrically-based safety-related systems.
A major objective is to facilitate the development of
application sector standards.
Compliance to the
criteria set out in IEC 61508 allows manufacturers, systems
integrators and end users to demonstrate to customers that good
practice has been followed through the whole lifecycle and that
risks are being managed.
Purchasers of systems, or system components, are already
using the standard to specify their performance requirements in
terms of safety functions that have to be considered.
IEC
61508 is based upon risk assessment.
The standard requires investigation based on evidence to
judge functional safety.
It calls for independent assessment and recommends
minimum levels of independence all related to the consequences
of failure of the system, and to the safety integrity levels of
the system.
In
September 2001, Sira Certification Service became accredited to
certify the Functional Safety Capability of organizations
against IEC 61508 using the CASS scheme as the vehicle.
The scheme is now being developed to certify other phases
of the safety lifecycle including ‘product’, systems and
operation and maintenance.
CASS
(Conformity Assessment of Safety-related Systems) is the
framework used by third party accredited certification companies
such as Sira to assess and certify organizations to requirements
set by IEC 61508.
The
CASS scheme provides a structure whereby third party accredited
certification bodies can offer conformity assessment
certification for all activities within a safety lifecycle which
meet the requirements of IEC 61508.
The scope of the scheme will cover all those involved in
the specification, design, development, manufacture,
implementation, support and application of hardware and software
components and complete systems, across many sectors.
It will cover both off-the shelf products and application
specific systems and the operation and maintenance of those
systems.
The
benefits of the scheme are that it will:
- Enhance
confidence in the safety of complex E/E/PES systems through
the availability of an accredited assessment standard.
- Reduce
procurement costs by facilitating the re-use of assessed
product
- Reduce
long term operational and capital costs by facilitating the
use of a ‘building block approach’ using certified
components with recognized safety characteristics
- Reduce
design and development costs for systems that utilize these
components
- Generate
increased end-user confidence in current and emerging
technologies that can offer flexibility and cost reductions
without compromising safety
- Promote
international trade in certified equipment by providing
manufacturers with independent and internationally
recognized endorsement of their product
- Provide
a yardstick to national regulatory authorities assessing
‘fitness for purpose’ and best practice of installed
systems.
Accreditation
of the certification process is important as it gives
independent assurance of the competence of the certifier and
provides consistency of the results of the process.
It facilitates recognition of certificates
internationally through mutual recognition agreements.
Insert
Route to Certification Diagram (Sira).
Sira
Test and Certification Ltd is the first certification body (in
the UK) to offer accredited certification to IEC 61508, by
providing a service to certify companies with a Functional
Safety Capability Assessment (FCSA). One company that has taken
advantage of this is Moore Industries who provide solutions for
companies who need to interface field processes with
computer-based systems and instrumentation.
Moore
Industries is a world leader in interface instruments for
process control, system integration and factory automation
(please visit www.miinet.com)
In
order to maintain and improve on high safety standards, process
companies are advised to ensure their procedures incorporate the
specification that products are supplied by companies whose
functional safety capability has been assessed and certified to
the standard. This demonstrates a strong commitment to safety,
meeting both industry and international standards to accredited
procedures. Using suppliers whose capability has been certified
will give engineers and other users the added security of
knowing that products have been manufactured for the paramount
safety of the industries in which they are utilized.
Sira
is now certifying the functional safety capability of clients
against IEC 61508. It
is also developing the certification of other phases of the
safety lifecycle such as component and system certification and
the ongoing operation and maintenance of systems by users.
To
ease the introduction of the standard, the IEC intends to
publish an introduction to
IEC
61508. For more
information please contact the IEC or visit their website www.iec.ch
Sira
provides training and generic advice to organisations wishing to
comply with IEC 61508 and can arrange for a preliminary review
of an organization’s safety related system against the
requirements of the standard. For more information contact Sira
on + 44 20
8467 2636 or visit the website www.siraservices.com
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