FIRE SAFETY
Fire prevention systems – you get what you pay for
Lee James, General manager – Product Marketing, at fire detection equipment specialist, Nittan Europe, cautions against cutting corners on fire detection systems in hospitals and other healthcare premises.
Life safety systems, such as fire detection systems, perform one of the most valuable of building services – they save lives in the event of an emergency. Their importance is such that they are heavily regulated, with standards relating to product design and manufacture, system design, and installation. No reputable organisation readily opts for a fire detection system that doesn’t meet these standards; the results could literally be fatal. However, specifying or installing a fire detection system, or even elements of that system, that meets all the standards, but errs towards the cheaper end of the product spectrum, can bring its own set of problems, and may well find you paying a higher price one way or another. Here, we look at key aspects of fire detection systems that are impacted when you cut corners and opt for low-cost, low- quality product.
Detection algorithms An algorithm is a set of instructions designed to perform a specific task. It takes input and changes the data according to the preset ‘instructions’ to create an output. In fire detectors, that input includes smoke and non-combustion products such as steam, aerosols, and dust. The sophisticated part of the process is to identify and differentiate these, and only activate the sounder in the presence of smoke. If the sounder is activated when only non-combustion products are being emitted, then that is a false alarm. False alarms are more than just annoying; they can be distressing, especially among more vulnerable people such as hospital patients. They are also a costly waste of public resources. The latest government figures for England (Fire and rescue incident statistics, England, year ending March 2020, Home Office) show that of all incidents attended by fire and rescue services, false fire alarms made up 42%, compared with actual fires, at 28%. There are many types of different fire detection algorithms in use, and you get what you pay for. Go with a cheap fire detection system, and you leave yourself open to a greater risk of potential false alarms. A quality fire detection system, on the other hand, employs advanced detection algorithms which are able to
Nittan’s EV-DPH sensor has a large information capacity.
clearly distinguish between smoke and non- combustion products, providing extremely reliable fire detection without – or with considerably reduced – false alarms.
Transmission protocols
At the heart of all commercial analogue addressable fire detection systems are control panels. When a device’s detection algorithm has identified smoke, the output data needs to get back to the control panel as quickly as possible. This is achieved through the transmission protocol – the system’s ‘language’, and, just as with languages the world over, there are plenty of different protocols.
Interestingly enough, the most commonly used protocol in the fire industry, which is square wave pulse-based, is not the best; it’s quite susceptible to noise and interference, and has limited information capacity. Does this matter? Well yes, very much so. Noise and interference can compromise system operation, showing devices as missing when they are not, and leading to a corrupt data warning on the panel, all of which will require an engineer site visit. In the worst case, it could lead to a false alarm, and an unnecessary visit from fire and rescue services. When looking at information capacity, if a system can only cope with limited data, then its ability to determine what is and what isn’t a false alarm is restricted, as is your choice of devices, since you will be unable to use more ‘intelligent’ ones. For example, Nittan’s EV-DP and EV-DPH alarms with dual optical alarm technology require more capacity than a standard multi-sensor or a single sensor device.
A peer-to-peer network control panel allows for easy changes to the fire detection system.
One protocol that avoids these issues is the Sine Wave, Frequency Shift Key (FSK) protocol, but it comes at a higher price. However, it does bring further benefits, including very high speed transmission, minimal transmission errors, the ability to take more inputs/outputs, more controllable features, and more type codes for devices; in addition, it is not affected by the number of devices on the loop. This makes it not only highly reliable, but equally
September 2021 Health Estate Journal 85
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