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Retrofitting obsolete alarm annunciators

Author : Gary Bradshaw, Omniflex

04 October 2021

When it comes to industrial alarm annunciators, many facilities suffer from issues relating to obsolescence management. As many former alarm system manufacturers are no longer in business, sites haven’t updated the original systems that were installed decades ago.

Image: Shutterstock
Image: Shutterstock

(Click here to view article in digital edition)

Here Gary Bradshaw, Director of critical alarm specialist Omniflex, describes his experiences retrofitting alarm annunciators at a nuclear power plant in the Northwest of England.

The UK’s nuclear sector is rediscovering the importance of hard-wired alarm annunciators for monitoring their critical alarms. Heysham nuclear power station – Image: Shutterstock

When working for Londex in the 1980s, I installed my first alarm annunciator system for a new nuclear facility in the Northwest of England. During this time, there was a requirement for hard-wired, panel-based alarm annunciators featuring coloured-inscribed warning lights and the ability to monitor specific conditions from different areas in the facility. However, during the 1990’s, with the establishment of PC-based SCADA systems, these hardwired systems fell out of favour.

The golden age of digitalisation meant that industries could streamline their workspaces, getting rid of bulky annunciators and switch to compact, computer-based alternatives. Annunciator manufacturers like Londex, Babcock, Clifford and Snell and Highland either went into administration or were taken over by other companies.

Yes, increased capabilities of PC-based systems led to more efficient monitoring and reporting across a range of communication points. However, many companies overloaded their systems with alarms, leaving facilities reliant on complex displays full of complicated visualisations to warn them of imminent danger. This can be overwhelming for operators to look at, making it difficult to identify and act on critical alarms. In fact, this very problem is renowned for being a contributing factor to several high-profile incidents, including Buncefield and the fire at the oil refinery at Milford Haven.

Fast forward 30 years, the UK’s nuclear sector is rediscovering the importance of hard-wired alarm annunciators for monitoring their critical alarms. But, due to the disappearance of the original manufacturers, it’s difficult to ensure their existing hardwired alarm annunciator systems are fully supported and have spares available.

So, what options are available to these companies and how can retrofitting alarm systems save time and money?

Image: Omniflex
Image: Omniflex

Keeping it simple

The key for any annunciator is to keep it simple. Imagining a car dashboard, every time you experience an oil failure or engine malfunction a light flashes immediately to notify the driver of a potential problem. This means that as soon as you are able, you can pull over and address the issue to save from lasting engine damage.

The same principle should apply in any industrial facility. When specific abnormal conditions occur, for instance if there is a radiation leak or an unexpected temperature change, operators must be notified immediately so they have time to prevent dangerous events from happening.

It is easy to assume your existing old alarm system is working adequately so why would you want the inconvenience of upgrading your annunciators and spend the time and money replacing them?

Well, because many of these systems were first installed decades ago and companies often now find themselves unable to purchase spare parts or get any support. What’s more, many older systems were made before IEC61508 SIL requirements were introduced, meaning that many companies could be operating without meeting the correct SIL compliance standard.

This is why companies should seek help to retrofit modern SIL rated alarm annunciator systems. Not only can companies upgrade their existing alarm systems at minimal cost and disruption, but they maximise the safety of the facility.

On the nuclear site in the Northwest of England, existing Londex alarm annunciators have been replaced by SIL rated alarm annunciator systems. It is a testament to this customer that they still see the importance of hardwired alarm annunciators for plant safety after 30 years.

Gary Bradshaw, Omniflex
Gary Bradshaw, Omniflex

Keeping low costs

From my initial experiences in the 1980’s whilst working with Londex, it became clear that senior staff at industrial plants were concerned about installation costs and downtime associated with installing new systems. They saw it as more cost-effective to hire staff to physically monitor the conditions in a facility rather than having functioning alarm annunciators networked to a digital system.

But retrofitting a new alarm system needn’t be costly or inconvenient for operators. Experts can design and manufacture a system that will be made to replace obsolete alarm systems from any manufacturer. By using the existing wiring and panel space, the new system will minimise any disruption and keep installation costs low. What’s more, all the new alarm systems will be engineered and tested off-site to help reduce installation time and disruption to a plant’s productivity.

The importance in digitalising data from communication points around a facility, which was realised in the 90s, mustn’t be understated. Alarm annunciators should give local visual indication and sound audibly around a facility to notify operators of an abnormal occurrence. In addition, these alarms would benefit from being logged either on a web-based server or a local SCADA system. This will then provide historical pre and post alarm logged data which is imperative for auditing and compliance purposes.

What’s more, thanks to the modularity of modern alarm annunciator systems, adding in mobile phone connectivity is easy. In the event a facility is unmanned – which may now become more likely in a post-pandemic world – alarms can be sent via SMS and email to the relevant personnel so a resolution can be reached efficiently.

Not providing the correct critical alarm information quickly and with a clear message to the operators has resulted in detrimental cost, loss of life and environmental damage in the past. With so much at stake, it’s vital that mission-critical industries like the petrochemical, oil and nuclear sector take action to replace their outdated and obsolete alarm annunciator systems.

About the author:

Gary Bradshaw is Director at Omniflex, a global specialist in remote monitoring, protection and critical alarm systems. Having qualified as an engineer at GEC Switchgear, he went on to establish the Conlog brand in the UK and was later part of the management buyout by Omniflex in 1997. Over more than twenty years, Gary has grown the business from a start-up to a leading remote monitoring brand across many industrial sectors.


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