In the simplest explanation, a smoke detector senses smoke and can help in case of an emergency so you can evacuate the building. In most cases, smoke is a fire indication. There are two main classifications for it – household and commercial detectors. The main difference lies in how the signal is issued. Household smoke alarms trigger a visual or audible alarm from themselves or several interlinked detectors. On the other hand, a commercial fire alarm signals the system. It issues an audible or visual alarm. Commercial buildings usually also use sprinklers.
These are mounted on the ceiling and are inside a plastic enclosure. Its sizes and shapes vary and depend on the manufacturer. They are typically like a disk.
Before smoke detectors existed, there were heat detectors. These devices sense heat and are the oldest form of detecting fire. A mechanism inside it responds when it meets a fixed temperature or when there is a sudden increase in temperature. Using heat to identify potential fire was not fast enough, especially in large areas where heat takes time to travel.
Carbon monoxide detectors can identify smoke either by ionization or photoelectric. Some models can do both.
| Alarm manufacturer | City of their headquarters | State |
|---|---|---|
| First Alert | Aurora | Illinois |
| Kidde | Mebane | North Carolina |
| Nest | Palo Alto | California |
| BRK Brands | Aurora | Illinois |
Photoelectric
It responds best to slow-burning fire, where smoke is present but little to no flame. The photoelectric fire alarm uses a light source and a photoelectric sensor to determine.
Smoke travels to the chamber and passes through the light beam’s path. The smoke particles scatter the light, aiming at the sensor. As a result, the detector triggers the alarm. Depending on the model, some send out sound and light. Others only sound.
Ionization
An ionization smoke alarm is the best choice for fires that burn fast. Its chamber contains radioactive material. When it passes through two charged plates, it creates an ionization chamber. Air is ionized, and current flows through the plates. If smoke travels into it, alpha particles are absorbed and disturb the ionization. The current reduces, and the alarm is triggered.
Combination
This type is a combination of photoelectric and ionization. A combination alarm contains the parts of a photoelectric and ionization. As a result, it increases its sensitivity to fire. Using both these technology increases your protection against fire.
In most cases, residential fires include a combination of slow-burning and raging fires. It is impossible to predict which one might strike, so having both makes a world of difference. You will get notified of the early signs of fire, regardless of time and whether you are awake.
General Operation Procedures and Placement
Assuming you know your needs and have decided on what to purchase, it is time to find out how many pieces of alarms you need and where to attach these at home.
Per guidelines from the National Fire Protection Association, you should place it in the following locations:
- At least one unit per floor level
- One unit in each bedroom
- One unit outside every sleeping area
Houses with a wider floor area will need more units than smaller ones. Getting a smart home system will do you wonders if you have the extra cash to spare. Your mobile phone and control panel will receive any notifications from the system.
How do I get the best coverage and protection at home?
You can purchase what you don’t have if you only have an ionization or photoelectric detector. If you have an ionization alarm, you can buy a photoelectric one and place it right beside the existing one.
However, not all the time do you know what type of detector you have at home. If that is the case, you then better check your manual. If that is no longer available, another option is to look at the back of the smoke detector. These would usually have a label with the type printed on it.
Another option you might want to consider is replacing these individual smoke units with combination alarms if budget is not an issue. These units have dual sensors in them working together.
