The survivability of fire detection and alarm systems


Share this content

Paul Pope, Group Business Development Director at Global Fire Equipment (GFE), speaks exclusively with IFSJ about the survivability of fire detection and alarm systems

Earlier this year, Global Fire Equipment (GFE) hosted an industry roundtable on the subject of survivability of fire detection and alarm systems. IFSJ sat down with Paul Pope, Group Business Development Director at GFE to understand the importance of system survivability and get an overview of the key points raised during the discussion which saw representatives from across the fire industry come together to discuss this important topic.

Can you define survivability?

When used in relation to fire and life safety systems, the term ‘survivability’ relates to capability of the entire fire alarm system to perform properly and remain fully operational, while under attack by fire.

Some fire detection and alarm system (FDAS) just need to initiate an alarm if a suspected fire is found, but for other systems that require a phased or complex evacuation, the FDAS needs to be able to continue working while the fire is occurring so that the fire management authorities can establish the location of the fire and monitor its spread. This information is essential to ensure a safe and controlled evacuation. If the FDAS is badly designed, it could fail relatively quickly. Premature failure of a FDAS could be catastrophic as vital information will not be provided to the fire and rescue services.

Failure in one area due to poor survivability could result in the system being unable to activate audible and visual alarms to warn people of the imminent danger. In the case of a phased evacuation, the system might be incapable of further evacuating another alarm zone area where the fire is spreading to. If all the detection control panels are located in one area and there is a fire in that area, for example, the entire FDAS would be wiped out in a matter of seconds.

What was the key focus for the roundtable?

GFE hosted the industry roundtable to better understand the differing views on survivability across the sector. I was joined by Chris Taylor, Associate Director at engineering professional services consultancy WSP, Simon Hopkins, Marketing Manager from cable systems manufacturer Prysmian Group, Steven Daws, Senior Consultant & Quality Manager from independent fire consulting practice CS Todd & Associates.

The debate was very thought-provoking and highlighted that although a number of industry standards relating to survivability already exist, they each have a specific focus and there is no one piece of regulation which stipulates the need for the overall survivability of a FDAS.

Although there were differing views on this topic, there was a consensus that FDAS survivability should be a shared responsibility and that achieving survivability – and greater awareness of its importance – will require an industry-wide collaborative approach. We discussed the fact that there is no clear industry performance specification for FDAS survivability. How the standards are achieved comes down to the design, installation and system commissioning process. This is where the problem lies.

There are many different factors that determine the survivability of a FDAS and unless it has been designed with survivability in mind from the outset – and each individual element of the system is capable of surviving for the length of time required by the building and its evacuation strategy – the risk of system failure is high. Engineers have to understand the fire risks associated with the whole system to ensure continued fire and evacuation strategy and system design compliance.

The foundations for improving the survivability of fire detection and alarm systems are already there thanks to the existing regulations, however, rather than introducing more regulation, we all agreed that the emphasis now needs to shift onto education and raising awareness across the sector about why survivability is such an essential consideration when designing FDASs.

How long should a fire alarm system be able to survive while under attack?

It is often assumed that the different elements of the FDAS only need to survive for 30 minutes before they can fail, but this is not long enough in complex buildings such as large residential buildings, offices, shopping malls, airports and hospitals. Complex buildings must be actively assessed as a single, coherent system of interdependent components. In these types of buildings, the design and the connectivity of a FDAS and the building’s evacuation system have to last much longer than 30 minutes.

BS 8519 takes into account the need for different survival times of fire-resistant cables and recognises three fire survival times according to the specific life safety or fire-fighting application: Category 1 – 30-minute fire survival time; Category 2 – 60-minute fire survival time; Category 3 – 120-minute fire survival time. If these category times are specified for cables on a project, for example, then the design of the whole FDAS must follow the same survival time criteria to ensure the entire system is capable of lasting that long. This requires careful consideration of which fire detection and alarm equipment to use, where to locate the equipment and where the equipment is controlled from so that it does not fail early and therefore negatively impact on the required fire survival time of the cables.

Specifiers need to fully understand the intended use of the building and its detailed fire/evacuation strategy, engineers must understand the fire risk experienced by the whole system to ensure continued fire/ evacuation strategy and system design compliance, and those responsible for procurement need to manage expectations of survivability performance.

In our discussions, we agreed that an intrinsic approach is required to having an overall survivability time that those responsible for each element of the system should adhere to. Survivability should be a prerequisite of all complex systems and each building needs to be assessed on a case-by-case basis. As an industry we have a shared responsibility to better understand how to deliver survivability of fire and life protecting systems during an emergency.

What design considerations should be made when choosing a survivable fire alarm system?

One way in which GFE is leading the way in system survivability is our inbuilt mesh network. We have developed our Chameleon multi-master, multi-path peer-to-peer network which is a fundamental departure from previous fire alarm control panels’ (FACP) networking arrangements in that it creates an extremely resilient infrastructure for the management and interaction between multiple FACPs in a single system. A fully closed loop and multi-path solution, it addresses and overcomes the limitations associated with traditional RS485 multi-drop topology.

When RS485 multi-drop topology is used, there is no redundancy in the network which means that in the event of a short circuit in the cables, for whatever reason, all interaction and communication between the different FACPs would cease because the information can only travel from node to node in a linear manner, to the left or to the right. In comparison, however, the Chameleon multi-master, multi-path peer-to-peer network has point-to-point communication across the entire network.

The network’s FACPs and other devices are directly interconnected via a dedicated ring topology link and can communicate bi-directionally. This means that in the event of a part of the network being lost, the remaining nodes will not lose their sub-networking capability. As each segment of the Chameleon network is galvanically isolated from all the others, the network also has superior immunity to electrical interference, further enhancing the overall FDAS’ survivability.

Where does the industry go from here regarding survivability?

The roundtable highlighted that one reason for the low profile of survivability of FDASs is due, in part, to the siloed approach taken by the sector whereby those specialists responsible for developing the regulations are focused on their own individual priorities. Key to increasing awareness of the issue is helping people to understand the regulations that are already in place.

As Chris Taylor explained: “When it comes to matters such as survivability of fire systems, we need to move away from the silo mentality that often permeates many aspects of the fire safety sector. Pushing the survivability of fire safety systems higher up on everyone’s agenda will take a coordinated approach and there needs to be clear lines of responsibility as to how we move from debate to action.”

Our industry roundtable and the collective experiences of those participating have demonstrated that there is a clear need for greater transparency about survivability times in performance specifications to ensure that survivability is achieved. This would help to create a level playing field where everyone understands, expects and quotes to an agreed specification.

We need to take a proactive stance in pushing for FDASs to be designed for survivability from the outset rather than as an afterthought. But there is also a need for greater awareness about survivability among those responsible for specifying, procuring, installing and using fire and life safety systems. Everybody has a part to play in ensuring that the operation of a building’s fire protection measures are maintained, and everything has to come together: from the design and specification through to installation.

This article was originally published in the August edition of IFSJ. To read your FREE digital copy, click here.

Receive the latest breaking news straight to your inbox