The next generation in fire detection
June 2018, IS & Ex
The fire engineering industry, which offers a crucial life and property saving service to the world, it used to be based on plain old heat and smoke detection. Then technology got a little cleverer with optical/heat point type detectors. Some smart vendors also added carbon monoxide detection for good measure. As infrastructure started to evolve that did not suit point type detection, such as data centres and high-bay warehousing, air sampling devices were introduced. Then came very early warning smoke detection systems, more commonly known as high sensitivity smoke detection systems (HSSD).
This technology brought about a push forward to sense combustion early. The primary need is to reliably sense a fire at its earliest stages in order to illicit an alarm and then take immediate action to minimise injury and loss. Nevertheless, this technology is hamstrung by the fact that there is always a false alarm potential when optical only smoke sensing is used, for instance lasers and LEDs.
To elaborate, smoke particles are similar in size to dust particles. When either phenomena is sampled and analysed by the optical sensing mechanism within very early warning smoke detection systems, light is scattered in similar ways resulting in the detector possibly making an incorrect decision that there is a fire, and signalling an alarm. Manufacturers of such systems have tried various methods to mitigate this, mostly with costly dust filtering systems that require continuous and onerous maintenance.
All such air sampling devices that utilise optical sensing are in essence ‘smoke detectors’. However, right now, there is a next generation air sampling system available that can sense an impending fire threat accurately and reliably, and can do it prior to any smoke even being emitted.
The Cirrus Hybrid is a ‘very early warning smoke and fire air sampling detector’. It utilises multi-sensor technology, which is not tied to the limitations of optical only smoke detection. The key reasons behind the development of this revolutionary new product is to answer the high demands of a world now well into the ‘Information Age’.
There are data centres all over the planet hosting consumer data ‘in the cloud’. Such infrastructure requires densely packed hard disk drives, networking infrastructure, densely packed electrical power cables, as well as data cables. All of which have varying polymers that combust differently.
Some produce little or no smoke, while other polymers emit thick black smoke. Gone are the days of having a few air conditioner units scattered around. Cooling systems have become far more sophisticated incorporating hot aisle/cold aisle containment systems. Air is being moved at high velocities. Dust is present in ceiling and sub-floor areas. Data centres by their design work against fire detection systems, but many are required to have automatic fire extinguishing systems installed, as most insurers insist on it.
Those older very early warning detection systems offered an attempt at solving the fire sensing issue by detecting the earliest signs of smoke, but many engineering standards steered away from the use of such devices to trigger the operation of automatic fire extinguishing systems because of the inherent false alarm potential. Such standards, like BS6266/SANS246, recommend that air cooling systems be turned off to allow point type smoke detectors a chance to sense smoke and therefore provide a second separate signal to operate the automatic fire extinguishing system. If the decision was left to the limitations of the optical sensing mechanism alone, dust could trick it into thinking there is smoke from a fire, creating a false alarm and possibly leading to the costly unwanted operation of an automatic fire extinguishing system.
The Cirrus Hybrid is not affected by such limitations since it combines two separate detection mechanisms in a single system. It has optical smoke sensing similar to all the other types of very early warning smoke detectors, but it also has a cloud chamber. This is a ‘combustion detector’, not a ‘smoke detector’. It looks for invisible combustion particles that occur before smoke at the ‘thermal particulate’ stage of a fire. The Cirrus Hybrid continually asks its different detectors for their status. In order for it to decide that there is a genuine fire, the cloud chamber must confirm, thereby dismissing false alarms from dust, humidity and other phenomena that plague older optical only detectors. Should smoke be emitted during a genuine fire, the smoke detectors create a smart ‘boost’ signal that further reduces response times.
The advantages of convergence
One of the major advantages of the Cirrus Hybrid is that it reliably responds to different kinds of fires. It can sense when polymers electrically overheat – but emit little or no smoke – far in advance of an optical only fire detector. Fumigation systems that produce high amounts of obscuration can also fool optical only type very early warning smoke detection systems. The cloud chamber is not so easily fooled. Many of the largest and most prestigious data centres are now employing this technology to not only detect fire, but also to provide a reliable set of signals to operate automatic fire extinguishing systems.
The convergence of technology means that this fire and smoke detection product sits at the cutting edge of possibility. It utilises a 7” full colour touchscreen for easy navigation and use. It stores around two months of historic fire, smoke, air flow data. It can also enhance itself by being integrated into a client LAN IP network. It can interact with IP security cameras and broadcast what such cameras see on the Cirrus Hybrid’s touch screen, allowing an impending fire threat to be investigated without having to walk into a potentially dangerous situation.
Offsite remote viewing is also possible, which allows for remote technical support from a specialist, all via the Internet, thus minimising cost and time when technical intervention is required. Furthermore, the Cirrus Hybrid is both a fully addressable and conventional type detector making it compatible with any reputable fire control panel. It is loaded with the Protec Algotech Protocol for use on the Protec Addressable range of fire control panels. Thus, each pipe is an addressable device that can provide multi staged alarm levels per pipe.
By combining both smoke and combustion detection principles, by converging fire detection with security system technologies, by being loop enabled with addressable fire control systems, the Cirrus Hybrid represents the next technological step in the advancement of fire detection. The time for reliance on old technology solutions has passed – long live the future.
For more information contact Grant Wilkinson, Alien Systems & Technologies, +27 (0)11 949 1157, firstname.lastname@example.org, www.astafrica.com