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Safety and EMPHASIS

Omniflex supplies safety critical alarm systems throughout the world working closely with the HSE guidelines and EEMUA 191 standards. This ensures that critical alarms are distinguishable from other operational alarms and that these alarms are limited to the number that an operator can effectively monitor and that the ultimate plant safety should not rely on the operators response to a control system alarm.

When designing these types of systems Omniflex takes great care to ensure that the systems provide usability: meaning they are relevant to the user’s role at the time, they indicate clearly what response is required and that the alarms are to be presented to the operator at a rate that they can deal with effectively and efficiently. It is important to ensure that the contribution of the alarm system is clearly identified when protecting the safety of people, the environment and plant equipment and that the systems performance is assessed not only at the design stage but also during commissioning ensuring it is effective and usable under all operating conditions.

All Omniflex critical alarm solutions are engineered to the highest standards at all times. As part of the initial discussions phase Omniflex engineers will assist with the IEC61508 FMEA study providing all the relevant MTBF, MTTR and PFD data to assist in establishing the right solution.

Since the early 1970’s Omniflex has been supplying SHE (Safety Health and Environmental) Alarm systems to many industries across the world, the mid to late 1970’s saw these systems becoming more intelligent and with the need to reduce panel space etc the footprint of these hardwired alarm annunciators became smaller and became microprocessor based. It was at this time that Omniflex launched its Omni range of Alarm Annunciators which have become the world’s leading Alarm Annunciator systems to date. Due to their popularity and the increased awareness of needing proven in use safety critical alarm systems and the new standard SIL (Safety Integrity Standard) IEC61508 the Omniflex alarm systems were chosen by the UK’s Nuclear Industry to be assessed and substantiated for use in SIL applications. Sellafield Ltd successfully invested in having our systems assessed as part of their EMPHASIS project.

As part of the overall critical plant alarm system Omniflex can offer everything from the signal transmitter, trip amp, alarm annunciator, top end operator interface and logging system. More recently many of these critical alarm systems use fibre optic cable cores for each individual alarm signal keeping the integrity of the hardwired copper cables. Due to this Omniflex began manufacturing a single point fibre optic transmitter FCT and fibre optic receiver FCR. These modules are widely used across the UK’s nuclear industry as part of the safety critical alarm systems on their power station de-commissioning projects.

EMPHASIS Project

Safety is of paramount concern in the Nuclear Industry. In accordance with the requirements of the UK’s NII (Nuclear Installations Inspectorate), every nuclear site licensee in the UK must justify their safety case in order to operate. This involves substantiating the safety certification of each instrument involved. With the increasing reliance on “SMART” instruments in safety systems, the problem of substantiating the software in these instruments has been a concern of the NII for a number of years. The EMPHASIS tool was developed to assist the nuclear site operators to achieve a common level of substantiation whilst eliminating duplication of effort.

The EMPHASIS project has been adopted by NISIWIG (Nuclear Industry Smart Instruments Working Group) comprising of the major players from the UK’s Nuclear Industry. The EMPHASIS project is based upon a lifecycle approach as specified in IEC61508, and provides an evidence gathering tool in the form of a comprehensive set of questions covering all relevant aspects relating to the company and the product under review.

Due to the popularity of the Omniflex Omni 8/16 range of Alarm Annunciators in use across most of the UK’s nuclear sites for safety critical alarm monitoring this was one of the first instruments chosen to be substantiated. It was the first range of Alarm Annunciators to be substantiated in the world.