Anybody who has ever been involved in designing audio or visual alarm systems will be very aware of just how difficult it is to get it exactly right.
Not enough sounders and you are faced with the expensive and often embarrassing task of adding additional units after the job is finished and the walls have been painted.
Too many or too loud sounders and the inevitable complaints start coming in after the offices or plant is brought into service. Luckily with modern sounders the second problem can usually be solved by reducing the individual sounder volume if high quality sounders are used.
With the modern emphasis on providing visual alarms it is often difficult to decide exactly where to place flashers for maximum effect.
Our colleagues in E2S have compiled two papers which will prove useful for anyone who wants to increase their knowledge of audible and visual signals be they established engineers and designers or students who may be preparing for examinations.