Modern homes come with smoke and heat detectors fitted as standard. The Building Regulations specify the requirements that have to be met in relation to function and location.
Early models often gave false alarms because they were too sensitive in detecting smoke. Most of the early models would sound if you burned the toast for instance.
Later models have developed into a system that functions very well. The sensitive of the smoke detector has been turned down a bit, they will no longer sound if for instance if someone was smoking in the room, unless of course they blow smoke directly into the detector.
Different types of alarm systems have been developed; we would normally use two of them, smoke detectors and heat detectors.
Smoke detectors as the name suggests detects smoke in the atmosphere. It is important that they are located in the right places if they are to detection a fire at an early stage. The current requirement is for a smoke detector in the main living area and one at each level to protect the main escape route. They must be all interlinked so that if one of them activates they all sound at the same time.
Heat detectors also as the name suggests detects heat. These are used in garages and kitchens so as to not sound false alarms when cooking or when the car is in the garage. It is important that these are also linked to the smoke detectors.
For deaf people or people with hearing difficulties smoke alarms and heat detectors can come fitted with flashing lights or a vibrating pad that can be fitted under the pillow at night.
Smoke and heat detectors should be tested once per week and replaced every 10 years.