Fire Alarm Detectors (2)

Combined Smoke and Heat Detectors

Combine smoke and heat detector shall comprise of two chambers. One chamber containing the photoelectric smoke detector and the other shall contain the heat detector. The smoke detector shall utilize a horizontal optical bench construction which houses the detector and the optical sensor.

Fire Alarm Detectors (1)

1.     Photoelectric Detectors

Photoelectric smoke detectors use light and how it is reflected to detect smoke. Normally light is projected into a smoke sensing chamber inside the detector assembly. The light hits a black background of the chamber and is absorbed. When enough smoke enters the chamber it reflects the light on to a sensor inside the chamber. This causes the sensor to indicate an alarm. Photoelectric detectors are suitable for most applications giving the fastest response to slow burning fires - the most common start to fire events. Use of photoelectric detectors is highly recommended to provide coverage for escape routes due to their superior ability to detect optically dense smoke that would easily obstruct the use of escape routes.

Fundemantal of Fire Alarm System

In order to undertake the process of designing a fire Alarm and Detection system for a building it is essentially  necessary to have a full understanding, if not, the fundamentals of the relevant design standards, codes, ordinances, the legal framework surrounding building safety legislation and a sound working knowledge of product application theory. The following system design process is intended to give a reasonable overview of all the areas of knowledge required for the successful design of a fire alarm system. Due to the complex nature of legislation and design standards relating to fire alarm system design, this chapter will somehow serve as  a very useful source of background information to which further application specific detailed information can be added from other sources as required.

            Basically, a fire is a chemical reaction in which a carbon based material (fuel), mixes with oxygen (usually as a component of air), and is heated to a point where flammable vapors are produced. These vapors can then come in contact with something that is hot enough to cause vapor ignition, and a resulting fire. In simple terms, something that can be burn touches something that is hot, and a fire is produced.