Types of Smoke Alarms

A fire can occur at any time and it is best to be prepared at all times and safeguard your worksite and people on the premises against the hazards of fire. The choice of an early warning system, proper installation and maintenance of the same are critical to saving lives and minimising loss of property.

As we already know, fire alarms are broadly of two types: smoke detectors and heat detectors. In this article, we will be taking a look at the kinds of smoke alarms available.

About Smoke Alarms

Smoke alarms or smoke detectors can detect fires more quickly than heat detectors.

There are 3 kinds of smoke alarms: photoelectric, ionisation and a combination of both ionisation and photoelectric.

Ionisation Smoke Alarms

These contain a small quantity of radioactive material within the ionisation chamber.  There are two electrodes within the ionisation chamber with a space in between. The radiation from the radioactive material passes through the ionisation chamber which causes a current flow between the two electrodes. When smoke enters the ionisation chamber, it interrupts the current flow and triggers the alarm. The ionisation smoke alarm is the best to identify smoke caused by raging fires such as fires that are fuelled by flammable liquids or paper.

Photoelectric Smoke Alarms

Photoelectric smoke detectors work by using a light source that is contained in a light-sensitive electric sensor. These are positioned perpendicular to each other. Light is scattered by the particles present in the smoke when the smoke enters the optical chamber and cuts the path of the beam of light.  This hits the sensor and activates the alarm. Photoelectric smoke alarms are best to detect smouldering fires before the fire source bursts into flames. Photoelectric smoke detectors are sensitive to big combustion particles that are produced by slow burning, smouldering fires.

Combination or Dual Sensor Smoke Alarms

Combination or dual sensor smoke alarms work by using both photoelectric as well as ionisation technologies. Since ionisation smoke detectors respond more quickly to rapid and raging fires, while photoelectric smoke detectors work better in the case of slow, smouldering fires, dual sensor smoke detectors have both ionisation as well as photoelectric smoke sensors so that they can alert against both kinds of fires. It is recommended that a combination of smoke alarms be used as they safeguard against a broad range of fires and offer the best protection.

The choice of a smoke alarm rests on the layout of your worksite and the type of fire that is most likely to occur on the particular worksite. However, irrespective of the kind of smoke alarm or detector you select, proper installation, testing and maintenance of the device is very important.

The Cygnus range of state-of-the-art smoke alarms provide 24×7 detection and protection against fires and damage due to fires or smoke on all kinds of construction projects. Cygnus products have indeed changed the face of fire protection.