Laser spot detection under spotlight
01 March 2003
US-based Notifier sheds light on laser spot detection technology and indicates what makes it ideal for protecting sensitive data operations.
Early and accurate detection of smoke and subsequently fire is the key function of a smoke detector and this is among the many areas where laser spot systems score over aspirating ones, says the US-based Notifier.
Laser spot systems are gaining popularity particularly in sensitive data industries because of the host of advantages they offer, says the company.
"The expectations for early warning fire detection continue to increase as data processing and computer rooms, telecommunications facilities, cleanrooms, museums, and delicate medical areas take in more employees, and house more costly equipment and critical information," says a spokeswoman for the company. "A small amount of smoke can easily shut down these facilities and, in some environments, even a little downtime can mean disaster."
She elaborates: "In a data centre, for example, temperatures vary in the server rooms where intense heat is emitted and constant air-conditioning is required to generate cooling - this high airflow makes smoke detection difficult.
"In order to keep computer systems fully operational, a heating, ventilation and air-conditioning (HVAC) system must keep running to maintain stringent temperature and humidity requirements.
"False alarms from smoke detectors can interrupt the operation of an HVAC system and cause computers to shut down. Advanced detection systems, founded on state-of-the-art early warning detection technology, virtually eliminate downtime caused by false alarms in data facilities and other sensitive environments."
System designers primarily have two early detection technologies from which to choose: aspiration (air sampling) and laser spot (light-sensing). In the past, aspirating systems were accepted as the standard for high sensitivity and early warning detection, primarily because spot detection did not exist. More recently, the advancements in laser spot detection technology have captured the attention of systems designers, she says.
Aspirating systems are designed with tubular networks that draw air from fire protection areas to a central sensor, which is typically a single enclosure containing high-sensitivity optics. In order to sample air, these systems must be continuously aspirating.
For many years, these systems were the only detection solution available until the advent of laser spot detection systems.
While laser spot systems were once only known for their performance in clean environments, they now offer full adjustability in the control panel, making them an ideal solution for protecting many environments where rapid response and pinpoint accuracy are critical, she points out.
Comparing the two systems, she says: "Laser spot systems are designed to use patented on-board algorithms to check for the presence of smoke before alarming. An LED emits light into a highly intelligent sensing chamber, allowing the detector to differentiate between smoke and larger airborne particles such as dust, lint and small insects. Aspirating systems do not have this accuracy. With its sensitivity, balanced with high stability, laser spot technology can identify non-smoke particles as non-threatening, therefore minimising false alarms.
"The performance of laser spot technology is comparable to aspiration technology in an array of environments. In fact, independent tests have shown that laser spot systems respond as well as or better than traditional aspirating systems. Combined with flexibility, low cost and ease of implementation, laser spot technology is the logical choice.
"Installation of a laser spot detection system is generally simpler, as it does not require the complicated pipework and pipe maintenance associated with aspiration systems - and it is a system that is significantly less expensive across the board.
"Laser spot systems also offer more flexibility than aspirating systems. The tubing in aspirating systems requires unconventional installations and does not allow the integration of other types of detectors within its system. On the other hand, laser spot systems can be integrated with standard photoelectric or ionisation detectors on the same loop or system, offering more versatility if and when modifications are necessary.
"The laser spot system continuously supervises each detector and wire run in the system - this maintenance offers a huge advantage over aspirating systems. Offering limited supervision, aspirating systems cannot always detect leaks in piping or blockage of a port, factors that can alter the airflow and sensitivity per port in the rest of the pipe network. There may even be variations in sensing port sizes when the ports are 'cut', which can also affect sensitivity, delaying detection time.
"Additionally, unlike aspirating systems, laser spot systems are designed with an addressability feature, providing pinpoint accuracy in identifying the precise location of smoke or fire, thus reducing response time. Independent testing of spot detectors proved to be more accurate in determining the source of smoke than aspirating systems."
"With the numerous benefits of laser spot systems - cost cutting, flexibility, addressability, easy installation and minimal maintenance - it's easy to see why they've gained popularity.
"As a result of these significant advantages, as well as the increasing number of companies with operations involving sensitive data, laser spot detection systems are being recognised as a better, more effective option for early warning detection," she concludes.
Notifier, considered to be the world's largest manufacturer of commercial fire alarm systems, is part of Honeywell's Fire Solutions Group.
Notifier is headquartered in Northford, Connecticut, where it operates in a 302,000 sq ft state-of-the-art manufacturing facility.
Honeywell International is a diversified technology and manufacturing leader, serving customers worldwide with aerospace products and services; control technologies for buildings, homes and industry; turbochargers; automotive products; specialty chemicals; fibres; and electronic and advanced materials.
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