Smoke Alarms
cause of false alarms? And has the chamber been purposely designed for use in a domestic smoke alarm rather than simply copied from a commercial detector design? What would be wrong in copying a commercial design, you may ask. Nothing, except that they are designed to be stripped down for cleaning on at least an annual basis. As a result, there is no requirement to be robust enough to last up to ten years without any proper maintenance, as a smoke alarm sensor chamber probably has to be. All of these points should be serious considerations by a manufacturer but all are costly to effectively design into the product. They most certainly should be taken into account when considering which smoke alarms to stock.
Industry standard Another feature worth noting is the horn.
85dBA at three metres is the industry standard sound level and you can pretty much guarantee that the alarm will produce this. However, the horn assembly on all alarms are not the same. Most manufacturers use pressure contacts for the horn disc, because they are a lower cost option. This may not cause a problem, but if the unit is subjected to high levels of humidity (and they often are) there is a possibility that corrosion of the contacts could occur causing a failure of the alarm to sound at the critical time of a fire. Manufacturer testing of alarms is also an activity that you could argue separates the
stress testing is conducted and optical alarms have their sensitivity set by calibrating in actual smoke. Quality Assurance checks are carried out on all products at the sub- assembly, final-assembly and packaged stages. It’s a major task that has an impact on the price of the product but surely the peace of mind is worth that little bit extra.
Power source The other major consideration in ensuring
you purchase quality smoke alarms is the power source and security of it. It’s estimated that at any given time
around 50% of the nation’s battery smoke alarms are disabled. People remove the batteries to silence them, or to use in another device. Even if they leave them well alone, the standard batteries can be affected by changes in temperature, plus you have to rely on the resident to change them. The only reliable way to
overcome this is to use mains powered smoke alarms with rechargeable Lithium cell back up which
good from the not-so-good. Many manufacturers only batch test smoke alarms, which in our view simply isn’t good enough when you’re dealing with a life saving device. Aico alarms, for example, are comprehensively tested at several points of the manufacturing process, including at the Printed Circuit Board stage (In-circuit Test) and at the final assembled stage, where a Functional Test is carried out. Environmental
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can’t be removed like common PP3 batteries or used in anything else. Rechargeable Lithium cells also offer exceptional back up performance over a long period of time, but check that they are Lithium cells and not a PP3 battery, as these can be removed, despite any claims that they are tamperproof. But, don’t assume that all rechargeable cells are the same; the type of rechargeable cells used in the
product and the way the charging circuit is set up are extremely important. Both of these often overlooked points can have a significant effect on the reliability of the back- up supply.
Functionality Then we come on to added alarm
functionality and accessories, which will be more widespread with a good quality alarm. The ability to interconnect smoke alarms is
a requirement of BS5839 Part 6 and Building Regulations and any half decent alarm will allow for this. Interconnection can be achieved through hard wiring or, more recently, through wire free RF technology. The latter is ideal for retro fitting as it removes the need for ugly trunking or re plastering and decorating. Aico offers such a facility with its RadioLINK system in addition to a wide range of complementary ancillary products to tailor-make a system to specific requirements. So the question is are you going to risk
selling lower cost, lower quality alarms that may cause your customers considerable aggravation, and potential returns to store? More importantly, are you going to consider the implications if one of these low cost, low quality alarms does not operate effectively when a fire occurs? By only stocking an alarm that has been quality tested at all stages of manufacture and has been designed and built up to a standard rather than down to a price, can you rest assured that you have done all you can to protect yourself and those whose life may depend on you making the right decision.
www.aico.co.uk July 2010 Electrical Wholesaler 19
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