Protecting buildings from the risk of fire is never an easy task, and historic properties often bring their own particular array of problems: ornate decoration, irregular and high ceilings, lack of wiring and large indoor spaces. Optical beam smoke detectors are specifically designed to overcome these potential issues, with a number of features that make them inherently well-suited to protecting heritage and conservation projects.
An optical beam smoke detector transmits a beam of invisible infrared light across the building space to be protected, and is usually wall-mounted at near-ceiling level. A receiver detects and measures this light, and can recognise smoke interference anywhere along the beam path, triggering the alarm signal when the pre-determined threshold is reached. The receiver can be either situated directly on the opposite wall to the transmitter, or, more commonly, a reflective prism bounces the beam back to a single, combined transceiver unit.
This means that a single reflective beam system can protect an area of up to 1500m2
whilst only requiring wiring at one point on one wall – compared to a dozen ceiling mounted point detectors or a significant amount of ducting installation for an aspirating smoke detection system. As each unit is quite small, there is also a lot less visual impact, enabling safe fire protection without causing unnecessary damage to a building’s structure, decoration or aesthetics.
The Fireray 5000 from Fire Fighting Enterprises (FFE) is at the forefront of beam smoke detection technology, featuring installer and user friendly features such as motorised automatic alignment and adjustment, laser guided set up and dust build-up compensation. It has already been installed in many historically and architecturally significant buildings around the world, including royal palaces, cathedrals, museums and some of the world’s most famous temples of all faiths.
Reflective beam technology offers an ideal smoke detection system for large indoor areas and spaces where the architecture, decoration and aesthetics are important. They are also wall rather than ceiling mounted, which avoids problems with the vaulted, ornate or unusual ceiling designs that are often found in heritage properties.
In some instances though, there may be obstructions along the ceiling which could interfere with the beam path, making it very difficult to site a transceiver and prism without reflections from other things reducing the effectiveness of the system. For these situations, end-to-end beam systems are preferred, as extraneous reflections near the beam path do not affect an end-to-end optical beam. In an end-to-end system, the transmitter and receiver are on opposite walls, so any light reflected back at the transmitter has no effect, and any smoke entering the beam path anywhere along its length will still be safely detected by the receiver.
The Fireray 3000 is FFE’s latest product development, bringing the most advanced technology to end-to-end systems. Its housing is even smaller and more discreet than the Fireray 5000 as each head only contains one element of the system, and it does not require a prismatic reflector panel which may be undesirable in some environments. Because it is an end-to-end system, the clear pathway between the heads does not need to be as wide as for a reflective system, and as previously explained it will be unaffected by stray reflections. It does however require wiring at both ends, so for properties where this must be kept to a minimum a reflective system would be recommended whenever possible.