Is your Safety Instrumented System being proof-tested correctly?

Posted on 16/02/2016

If asked whether your proof test procedures for your Safety Instrumented Functions (SIF) were “good, bad or ugly”, what would be your response? The “good, bad or ugly” tag line was coined by ESC’s Engineering Manager of their Warrington office, Dave Green. He conducts regular seminars to aid companies in understanding the requirements for their proof testing procedures and achieving compliance with Functional Safety standards IEC 61508 and IEC 61511. These sessions explain that several main points will prevent mistakes and produce accurate results.

One such measure is to make sure the proof testing documents are legible to all parties. They need to be fully understood not only by the author, but by the technicians conducting the tests and those analysing them post completion. Assuming that the technicians have been trained to the same standard on all of the systems being tested, are the results recorded consistently, notwithstanding personal conclusions? Poor proof testing procedures may allow deviations when conducting the test and recording the results due to technicians interpreting the tests differently; this in turn, may lead to inaccurate results and records.

In-house policies, however strict, need to be revisited and constantly reviewed in order to prevent inaccurate proof test procedures. Are the failure modes under consideration fully covered by your proof test procedures? Can your proof test procedures demonstrate to the competent authorities that the full function and all failure modes are being tested?

Proof testing procedures efficiency works hand in hand with the correct competence levels for the personnel involved with your proof test procedures. This includes all parties; author, technicians and reviewer. How do you know that your personnel are competent to carry out their role to provide effective proof testing procedures and test completion?

As a general rule, safety procedures are met with a certain degree of respect. Policies are put in place to make sure that the failure of a system is a rare occurrence. Training is given, documents are reviewed and test equipment is checked and calibrated. But who reviews all the information gathered to validate the results? Is there someone in place to determine which calibration results need to be revisited and keeps a log on which tests have been completed with which test equipment? If a piece of test equipment fails its next calibration, would you know which of your equipment could be affected? Who makes sure that all areas have been covered and is in line with both company and HSE guidance?

Engineering Safety Consultants Ltd are a globally recognised engineering, Quantitative Risk Assessment (QRA) and IEC 61508 functional safety management consultancy, whose primary function is supporting clients in the functional safety aspects of the processes, systems and equipment for the oil and gas, petrochemical, utilities (including green technologies), military and manufacturing industries. They are able to help with management of procedures and raise awareness of hazard and risk. As an industry leader with a team of highly respected senior staff, they are currently nurturing a growing team of skilled safety consultants who can review and consult on all safety concerns. ESC provide insight. They impart knowledge and yield results providing reassurance to clients.

For more information on the services ESC can offer your business, please call our main switchboard on +44 (0)208 542 2807 or contact us here.

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