Beams, smoke, and mirrors

27 March 2009

Over 40 Fireray reflective beam smoke detectors have been installed in warehouses around Croatia by local installer Produktronika d.o.o.

Beams, smoke, and mirrors

Wide open indoor spaces like warehouses are particularly suited to the smoke detection capabilities of beam detectors, which cover huge areas with few units.

12 Fireray 50R and 100R detectors have been installed throughout two warehouses for furniture and carpentry company Elgrad in Zagreb; 17 F100R units are protecting high-profile health and hygiene product distributor Orbico's distribution centre in Inanić Grad; and 12 Fireray 100Rs are ready to detect unwanted smoke at a personal protection equipment company Lacuna's site in Sveti Križ Začretje. The Fireray detectors now form part of the fire safety systems fitted for these premises by Produktronika, along with Hochiki point detectors and Kentec control panels.

Beam detection technology is based on very simple principles, where the drawbacks of protecting a large enclosed space by traditional means are turned into advantages. Not only would large areas require many point detectors with intersecting fields of effect, but often the ceilings are so high up that smoke dissipation and hot air pockets can become a problem. Beam detectors can be mounted lower down on the walls below this 'air ceiling', and have a wide enough coverage area to be effective even when smoke has spread out.

Beams, smoke, and mirrors

At its most basic level, a beam of invisible infra-red (IR) light is transmitted across an area and a receiver detects the 'normal' amount of IR that successfully traverses that air space. When smoke from a fire enters the beam's active field, the particles interfere with the light's path and the level of IR received is therefore reduced. When this reaches a set threshold, typically 30% loss of signal, the alarm state is activated.

The Fireray 50R and 100R products use a single combined transmitter and receiver unit, with small reflective prism plates placed on an opposing wall, to detect smoke over an area of up to 1500m². Each beam's active field has a 7.5m radius around the direct path between the detector head and the prism, and the opposing surfaces can be up to 100m apart - which means a total area coverage of 1500m². for one single F100R. Up to 15 'point' detectors would be needed to safely protect an area that size, each bringing with it the additional cost of product, installation and cabling. If the beam is accidentally interrupted by a solid object, a 'fault' alert will be generated so that fire protection is not undermined.

The shape and layout of warehouse-like structures means that the Firerays can be at their most useful, with the spacious interiors perfect for beam detection. Similarly, commercial buildings like airports, shopping malls, theatres and even places of worship often feature the high ceilings and open spaces for which beam detection is ideally suited.

The F50R and F100R are very popular around the world for their effective reliability and discreet, small footprint, and form part of the fire safety systems for many prestigious locations across the globe: from royal residences in the UK to presidential ones in the USA, and from India's largest cinema chain to the world's tallest concrete hydroelectric power station in China.

Beams, smoke, and mirrors

For more exciting sites where might even be a tiny risk of explosion, the Fireray 2000 EExd is the only beam detector in the world certified to ATEX 94/9/EC standard for use in Group 2 hazardous areas. It uses separate transmitter and receiver units, and a low level control unit, each of which has achieved ATEX certification. The F2000 EExd also incorporates a drift compensation feature which reacts to maintain signal strength despite potential dust build-up or gradual building shift, reducing the potential for false alarms in areas where fire safety is so crucial.

The latest innovation in beam detection is the addition of an automatic, motorised aiming mechanism to the transmitter, which can effectively point the beam directly at the reflective prism and keep it aligned there even if their relative positions are caused to change. This makes installation and maintenance much easier, which is particularly important as the most common cause for complaint with beam detection is due to errors during the initial placement and setup. Recently, the Fireray 5000 product became the first and only beam detector in the world to achieve achieve LPCB (to EN54 part 12), UL (to UL 268) and ULC certification, and has now added to that list with approvals from French, Belgian, Swedish, Chinese and South Korean fire safety authorities.