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Aspirating smoke detection systems can give early warning of a fire but by their very nature, such fires stay small so rarely get much media coverage. Peter Massingberd-Mundy puts things right and gives them their fifteen minutes of fame.
This article includes several instances where early warning aspirating smoke detection ASD has done it’s job. The examples given provide an answer to the common question: “What evidence is there that early warning smoke detection works?” Of course, what people want to hear are full details, accurate references and undisputable evidence that early detection of a fire averted a certain catastrophe. Unfortunately it is not always possible to provide such details because the matter is encapsulated in a double ‘Catch 22’.
Firstly, and most obviously, the very fact that an early warning smoke detection system operated and action was taken to investigate and mitigate the circumstances – before they escalated into an uncontrolled fire – means that a catastrophe did not happen, so these instances are never major news. After all, if a fire is detected early it is not really a ‘fire’ – and unfortunately there are no statistics collected on ‘near misses’ in the fire industry! Secondly, and more subtly, the near misses themselves are often caused by some management or technical flaw which, with the benefit of hindsight, should not have happened. As such, the organisations involved are reluctant to publicise the details which may draw attention to their own shortcomings.
So this article demands an element of trust; trust that the examples given are indeed accurate summaries of some real instances of early warning detection and are not wholly fictitious. The only assurance I can give is that all the cases here are based on conversations with the people who were actually present at the incident, include substantiated facts, and are not embellished.
Burn out
The first example is not uncommon, and was caused by an office fluorescent light fitting burning out. The offices in question were protected by an aspirating detection system which, however, was not physically connected to the fire alarm system, as the code-compliant ‘house’ fire system was based on point detectors. However, the incident was discovered when the first person entered the building at 8.30am to see that the aspirating system was reporting an ‘action’ alarm. Nothing untoward was obvious in the area but it was observed that one light fitting was not working. On closer inspection, it was found that the ballast on the fitting had burned out during the night, and the evidence from the aspirating system’s event log was used to identify the exact moment when it had occurred. Clearly, the incident was successfully detected by the system while there was no response from the ‘house’ system. However, the fact that no immediate action was taken shows a flaw in the management of the premises though fortunately, the incident did not escalate and there was no disaster. There is a second example of a similar incident where the light fitting in a large retail sports facility was reported to have been dripping molten plastic on packaging material below. While I have not personally spoken with anybody to substantiate this report. it is often cited in presentations.
Another case relates to a warehouse in the north of England. The incident was sufficiently serious to appear in the local press as several fire appliances attended the fire. Fortunately the fire was brought under control relatively quickly and the warehouse manager was quoted as saying that the timely arrival of the rescue services was attributed to the fact that they had Vesda aspirating systems installed in their warehouse.
The next case is an installation which protects rolling stock including sleeping cars, open saloon cars and dining cars. On one occasion a railway service man, while walking past a train housed in the maintenance block, noticed that the train’s air conditioning was inexplicably off. On entering the train to check the systems, he noticed that the VLF-500 was in alarm and upon investigation, smelt smoke. The investigation led him to the on-board toilet and a small electrical fire emanating from a faulty hand dryer. In this particular application, the aspirating detection system is interlinked to alert the driver and is also configured to turn off the on-board air conditioning when smoke is detected. Clearly with no driver present in the maintenance block, it was fortunate that the man was alert enough to notice that the air conditioning was off and to follow up on the matter.
Another instance relates to the detection of unauthorised hot work in a large power station in France. Quite simply, an aspirating system installed in a floor void detected smoke produced by illicit soldering work by a lone electrician. Details of this incident are scarce, as the settings were such that a full alarm was raised and emergency procedures were activated. Subsequent investigation led to a more appropriate setting of the system, which would still alert staff to the same incident but would not precipitate shut-down procedures.
Metro systems
Aspirating systems protect a number of major metro systems across Europe, including those in several European capitals cities. The equipment protects power generation rooms, switch rooms and escalators. During trials in a capital city outside Europe, however, a major fire incident arose in a cabinet containing high voltage switchgear. A point detector positioned in the very near vicinity of the particular cabinet failed to detect the smoke. But the aspirating system on trial in the area protecting a nearby cable tray detected the smoke and alerted people to the incident. Needless to say, the trial was considered to be a success and an aspirating system is being installed throughout the network of switch rooms.
Heading further east, a foam product manufacturer in Singapore recently experienced a dislodged V-belt on a conveyor blower. The system detected the incipient fumes generated from the dislodged belt and raised an alarm, so that a staff member could shut off power to the blower before a fire started. The engineering manager for the plant said that if the fire had not been detected, it may have resulted in huge financial losses due to the production line being interrupted.
Several years ago a system detected a burnt out PCB in a cabinet in large computer room operated for one of the major pharmaceutical companies. Aspirating systems covered the room, ceiling void and floor void and were monitored by a management system. The alarm brought in firefighters who tried to locate the source of the alarm but after a reasonable time they gave up and left the building. Fortunately, the local maintenance teams had full confidence in the system so knew that the alarm was genuine. After a further hour searching they located the burned out PCB and confirmed their suspicions. While the overheated PCB did not actually transform into a developing fire, the fact that people were alert to the incident means that it would have been dealt with in a timely fashion had it escalated.
In 2001, a fire at a waste processing facility in Holland was detected by a system which had been selected because of its tolerance to dirt and dust. Despite being de-sensitised to tolerate such an environment, the system effectively detected the fire and the rescue services were called in sufficient time to prevent the total loss of the building.
My final example of an aspirating system working effectively relates to a re-occurring alarm in the office area of a major telecoms company. A careful inspection of the event logs confirmed that the alarm was occurring shortly after the offices closed every evening. It was eventually traced to the cleaner’s old vacuum cleaner which had an ‘dodgy motor’ and was on its last legs. A replacement cleaner (the hardware not the person) resolved the problem!
These are a small sample of the many instances reported to us, and have been selected to provide an insight into the variety of applications protected by aspirating detection equipment. Of course, there are also instances where the source of an alarm has not been identified, but the comprehensive event log and flexibility of configuration of the Vesda system means that unwanted alarms can be eliminated in all but the most challenging applications. We are always interested to hear of more incidents where early warning has proved successful and, as the nature of this article confirms, we will always respect and maintain confidentiality of any particular incident when
necessary.
Peter Massingberd-Mundy is technology and expert practices manager at Xtralis UK Ltd. www.xtralis.com