In large areas containing obstructions or enclosures, high-sensitivity smoke detection can be difficult. Infrared beam detectors may be unable to “see” across the field, while conventional “point” devices are either uneconomical or simply unsuitable. In such cases, a new unit from wide-area detection specialist Fire Fighting Enterprises can be used. By sampling air through a custom-designed pipe layout, the Laser Aspirating Smoke Detector covers an extensive area using just one or two detectors in a single wall-mounted enclosure.
Two versions are available. The LASD1 has a single laser smoke detector and a pipe length up to 100 m, offering a maximum sample area of 1,000 m2. The two detectors of the LASD2, attached to two 100 m pipes, will cover twice the area.
This model can be configured for “coincidence detection”: both devices must register a hazard before the system alarms.
Three user-configurable alarm levels can be set. A high performance aspirator and flow monitoring circuit ensure a constant flow rate, which is indicated on a 10-part LED graph. The graph can also be used to set high and low flow thresholds.
Applications for the LASD units include racking systems in warehouses, telephone exchange rooms, computer suites, clean rooms and cold stores. The units can also be used for underfloor or ceiling voids and the interiors of H&V ducts. Where definite enclosures are to be monitored – for example, prison cells – “closed loop” sampling ensures that the air is returned to the test area rather than expelled from the building.
To keep dust particles out of the detectors, in-line air filters are used. These are housed in removable, transparent cartridges for rapid inspection and maintenance. The system enclosures themselves can be optionally sealed to IP65 to ensure maximum protection against dust and water.
To monitor trends over a period of time, all data logged in the LASD unit can be downloaded to a computer via an RS232 Modbus port. The product is supplied with PipeTracer, a proprietary software package which allows pipe networks to be designed and modelled easily.
