An ionisation smoke alarm works by measuring the amount of ionized air in a room. When combustion particles enter the ionization chamber, they combine with air molecules to form an ionized gas. The electronic circuitry inside the chamber senses this change and triggers the alarm when a predetermined threshold is crossed.

Detects flaming fires

The ionisation smoke alarm is one of the best types of smoke detectors for detecting flaming fires. Unlike photoelectric smoke alarms, it responds faster to flaming fires. It works by detecting changes in the electrical field that result from small particles flowing through the air. The presence of smoke in the chamber will reduce the flow of ions, causing the alarm to sound.

Flamenco fires burn at a blistering speed. A working ionisation smoke alarm can save your life in this type of fire. These fires are often caused by flammable liquids or cooking accidents. A good smoke alarm must be able to detect both types of fires. Luckily, First Alert Dual Sensing Smoke Alarms incorporate both technologies in one device.

When comparing photoelectric and ionisation smoke alarms, it’s best to consider the type of fire you’re most likely to face. Photoelectric smoke alarms have a narrower detection range, allowing them to pick up a variety of fires, but ionization smoke alarms have a wider coverage range.

Detects small particles

An ionisation smoke alarm detects tiny particles of smoke in the air. The device works by using a tiny amount of radioactive material. The particles are harmless to humans, and the alarm is disposed of after its useful life. This method is used to detect smoke in many households.

One type of ionisation smoke alarm detects particles in small enough sizes to be detectable by a photoelectric smoke alarm. These types of smoke alarms can be used in kitchens or near open windows, but they are less effective in areas like stairwells and upstairs landings.

The best ionisation smoke alarms detect small particles in the air. These particles come from flaming fires that consume combustible materials quickly. Photoelectric smoke alarms, on the other hand, detect light-colored particles that may be more reflective. For the best protection, it is best to have both types of smoke alarms. Dual-sensor alarms are also available, which combine the two types of smoke detectors into one.

Detects foam-filled upholstery

If you’re looking to install a smoke alarm in your home, you need to choose the right one for the room you want to protect. Fortunately, there are a variety of options available. Some of these are very effective at detecting fire, while others are not as sensitive. To help you decide which one to buy, fire safety experts recommend that you buy one that meets British Standard BS 5446 part 1 or has a Kitemark. Ionisation smoke alarms are the most common and most affordable type of smoke alarm, and they are very effective in detecting fires, especially fast-burning ones. However, they are less effective at detecting fires that are slow burning or produce large amounts of smoke.

Another type of smoke alarm is called an optical smoke alarm. Compared to an ionisation smoke alarm, optical smoke alarms are more effective at detecting larger particles of smoke. These include the kind produced by slow-burning fires like foam-filled upholstery and overheating PVC wiring. They also have a marginally lower sensitivity to flaming fires.

Detects overheated PVC wiring

Smoke alarms can detect a range of different fires. A Photoelectric alarm detects visible particles of combustion, while an Ionisation smoke alarm is more sensitive to smouldering fires. The photoelectric type can also detect overheated PVC wiring and foam-filled furnishings.

The VEWFD system has a temperature threshold and will produce an alert response if the wiring temperature is exceeded. This limit is 650 degC. The PVC tests produced the lowest number of particles per square foot, while the FEP wire had the highest mass concentration and highest light scattering detector response. The peak particle densities are shown in Table 2.

The tests were conducted using both PVC and FEP wires. PVC produced an alert level response in the VEWFD system, while FEP wire produced no measurable response. As such, PVC wires are considered the safer option.