Choosing the type of extinguishing agent is just the first step in obtaining the best value protection for your premises. Chris Downing discusses the main features to look out for.
Less than a decade ago, fire suppression in business premises focussed on the protection of computer hardware and the data it contained. Today, off-site data back-ups are routine and the cost of replacing damaged hardware has fallen dramatically. But this doesn’t mean that businesses are less vulnerable to fire risks; it simply means that the critical risk has changed.
The critical component nowadays is the networking infrastructure behind the computer installations. The vulnerability of infrastructure is demonstrated all too clearly by the incident which occurred a few years ago in a Manchester telephone exchange, where a fire affected over 130,000 telephones.
As a result of this fire, which was described by the Greater Manchester Fire Service as ‘not too serious’, some businesses were affected for almost a week. Telephone call centres were temporarily closed and companies which use the Internet were badly hit. In addition, many banks were forced to suspend business as their security depends on using telephone lines, as does the operation of cash dispensing machines. Before long, shops and consumers were running out of cash and debit and credit card machines were also out of use. Not even mobile phone users were spared; many outlets were unable to provide top ups, and mobile networks also depend on the landline telephone network. Overall, it is estimated that the businesses affected lost up to GB pound 4.5 million over that period.
Businesses at risk
The results of a localised fire in a business premises can be just as devastating for the company involved. Even a small fire in a networking patch panel can halt a business and, if repairing the damage means extensive rewiring, it can be weeks or months before normal operations are restored.
The fast spreading adoption of VoIP technology, which uses the networking installation to carry telephone conversations as well as data, makes the situation more critical. A small fire now has the potential not only to disable the company’s computers but also its telephone system. And there is another important facet to the evolution of risk. In the past, the vast majority of threats to a business have been accidental. But recent events in London and elsewhere have shown that this is no longer necessarily the case. So now, more than ever, it is essential to pay close attention to the measures for safeguarding vulnerable infrastructure. Automatic fire suppression is essential but it can take many forms so it is worth examining the more important of these in detail.
Whereas chemical extinguishants were favoured in the past – particularly in halon-replacement applications – systems using inert gases offer many benefits. Not least of these is their effectiveness in flushing smoke and potentially corrosive combustion products from the fire-affected areas, minimising damage and simplifying clean-up operations. Even though a significant proportion of Siemens’ fire protection business is with chemical agents, inert gas systems are perhaps more favoured, especially as suitable venting arrangements can easily be incorporated into the design of a new building.
But even the best of systems gives limited protection when switched to ‘manual only’. During extensive halon replacement work carried out by Siemens Building Technologies, we discovered that manual-only operation was selected in a large number of instances, even though this potentially limited insurance cover and went against the employer’s corporate policy. Some users tend to disable automatic fire suppression, wrongly believing that the release of extinguishant would potentially harm them. Not true – most of today’s gas-based systems are completely harmless. The exceptions are those which use Carbon Dioxide. These are generally used in applications such as electrical switchrooms, which are normally unattended and where very rapid intervention is needed in the event of a fire.
Nevertheless, some systems we saw were left in manual mode – even when the premises were not occupied. In the case of one large data and document archive company, for example, manual mode was found to be permanently selected at several of the company’s premises, leaving them entirely without protection every evening and weekend! With modern installations that feature coincidence detection – two-stage alarms with a pre-discharge delay to allow evacuation – and safe extinguishants, there should be no reason to disable automatic operation at any time. These discoveries lead to an important conclusion: individuals have to be prepared to accept their part in ensuring that the systems are allowed to operate effectively, and it is essential that training is provided to make this clear. Proper training at handover, regular risk assessments and increased user contact during maintenance mean that this message is slowly getting through.
Choosing the extinguishant is only the first step. This and every other step in the process should bring in risk assessment to the ‘as low as reasonably practicable’ level, and do so as cost effectively as possible. The systems discussed are based on inert gas extinguishants, but much of what is said also applies to the company’s high-pressure chemical based solutions.
Protecting multiple risks
In larger commercial installations, it is often necessary to protect several risks on the same site. A good solution is to use a single bank of extinguishant cylinders, sized on the largest risk area, to serve the whole site. In the event of a fire, the contents of an appropriate number of cylinders are released and are automatically routed to the affected area by directional valves. An important benefit of this arrangement is that the costs can be significantly less than providing independent systems for each risk, since the costs of the system hardware and extinguishants are spread over all of the protected areas.
Again, compared to using individual systems for each area, much less space is required to accommodate cylinders. Furthermore, because the extinguishant is stored under pressure, the cylinders can be located at some distance from the protected area, giving maximum freedom in planning the layout of the installation. But discharge of the system into one area may remove protection from all areas until the empty cylinders are replaced or refilled. Even using independent systems for each risk does not entirely address all of these concerns as once the cylinders associated with a particular risk have been discharged, that risk is left without further protection until replacements arrive or the cylinders are recharged.
Considerable expertise is needed to achieve the right balance between the level of protection provided and the investment involved in providing that protection. An experienced supplier, like Siemens, is well placed to provide that expertise.
Permanently connected reserves
For single area systems where this temporary loss in protection poses an unacceptable level of risk, this can be addressed by providing permanently connected reserve cylinders. But this arrangement doubles the number of cylinders, which means that the costs of the extinguishing agent and hardware are also doubled, as is the cylinder footprint. Some customers with multiple independent fire suppression systems get round this by holding a bank of reserve cylinders – often termed an unconnected reserve – on site. After an incident, cylinders from this reserve are physically swapped with the discharged cylinders while these are refilled. After refilling, the original cylinders are simply put back into the reserve bank.
This arrangement allows cover to be quickly reinstated, and has the added benefit that the reserve cylinders can be stored in the location which is most convenient for the user. In larger installations, however, unconnected reserves may not be the best solution.
We recently supplied a directional valve system covering many large areas on the same site, where protection for the largest area alone required in excess of 300 cylinders. After discharge, it could have taken more than two weeks to remove and refill these cylinders and reinstate protection, so this would have been unacceptable to the client. The solution was to provide a single connected reserve serving the whole directional valve system. After an incident, simply operating the appropriate key-switch brings this instantly into service. Protection is, therefore, maintained for each of the protected areas while the discharged cylinders are refilled. Costs are, of course, higher than for a system without a connected reserve, but in this case they were still substantially lower than those for fitting individual systems – even without a connected reserve – for every protected area. No single fire-protection solution is appropriate for all users. Some need no reserve system at all – as a fire-watch while protection is reinstated can be acceptable – while for others, a fully connected reserve is essential.
Whatever the application, selecting the right supplier is the key to arriving at an optimum solution. The chosen supplier should not only have proven experience, but should also be able to demonstrate that it is investing in the development of products and services which address today’s changing risks, and which will continue to address new risks as they evolve in the future.
