A smoke detector construction
Mostly, smoke detectors are divided into two main groups. The first one embraces the set of inexpensive devices based on ionization of air. The second type uses a light beam to verify if the fire has broken. There are also combined devices, that uses both technologies. They are made to ensure the top security level. In the next paragraphs we will explain in detail why it is better to use two different smoke detectors or a single one with two technologies.
A smoke detector based on ionization
This device is the cheaper one. Its easy to understand the way it works. An ionization smoke detector is able to run current between two chambers filled with americium, a special element that ionizes air molecules. Since there is a potential difference between the electrodes of each chamber, ions will let current flow. When flame is coming out, the smoke particles will reach the detector and interfere with ions. They will not allow the current between the chambers, which breaks the electrical circuit and switches the alarm on. Generally, a smoke detector based on ionization uses a separate battery to run. Its capacity is enough to make the device run for several years without the necessity to replace a battery. However, it is recommended to check how the device works each month. There is an issue with such an alarm: It may be triggered accidentally. Such a smoke detector can register a flaming fire faster than the next alarm, more specifically, a photoelectric smoke detector. Speaking of which, the next paragraph is just about it.
A smoke detector based on a light-emitting device
This device is the expensive one. But we cannot tell that its price is too high: You can buy an optical smoke detector for as much as $50 or even less. This device is compiled of a light-emitting component (usually, its an LED), a photodiode, which receives the light, and a lens. An optical smoke detector exists in two main modifications. For instance, the alarm may have the receiver found directly in front of an LED. Once smoke reaches the sensor, it will detract the beam. The light intensity will certainly decrease, which breaks the circuit and sets off the alarm. In other variant, the photodiode is located on the either side of the beam. The light doesn’t reach the receiver in a normal situation. But once the fire appears, smoke will detract the light ray from its usual direction and turn it onto the receiver. The circuit will be complete, and the alarm will be triggered. As you can see, there is no huge difference between these smoke alarms modifications. As for its operation, an optical smoke detector will react differently to fires in comparison with an ionization detector. In case of a flaming fire, it will need a bit more time to register flame. But an optical smoke detector will recognize a smoldering fire much faster than its cheap equivalent. And this fact may actually bewilder a customer who wants to buy a smoke detector. That is why we are going to explain how to choose a smoke detector in the next paragraph.
How can we pick a smoke detector
This is an easy task. The general idea is to mount two smoke detectors–an optical one and the one based on ionization–in each room and on every floor. This will let you discover any type of fire in its early stage and get off the building quickly. On the other hand, you may face installation difficulties, because you need to make the same work twice in each room. Manufacturers took care of this issue, and they created dual-sensor smoke detectors. Such alarms boast of having two different technologies inside. Smoke detectors can be wired to create a system, so once one alarm is triggered, other detectors will react too. We need hardly mention that it will be easier to connect ten dual-sensor smoke detectors then twenty alarms of both types. As for the installation and maintenance of smoke alarms, visit the National Fire Protection Association website–they provide a full explanation on the subject, so we do not see any reason to repeat it.
Bottom line: A smoke detector or a smoke alarm is a must. The device is not costly, it almost doesn’t require any maintenance, and it will save your life in case of fires. For the highest level of safety, use both types of devices or a single detector with both technologies.