Fire Alarm System

HomeFire Alarm System

Explain in detail the system and circles fire alarm fire alarm and how to design

Introduction: It is known that the design of the fire alarm systems located entirely on the electrical distribution engineer

And also should be noted that this system is designed electrolysis depends on how the importance of the property and the extent of accumulation of the people and also the specific and other budget

The fire alarm system basically consists of three parts are: (sensor -controller – alarm)

sensor of fire alarm


smoke detector

His theory is based on something from the two:

– The presence of a light beam (optical) .. when a fire rising fumes cut off the light beam thereby acting the alarm

– Through a process of Ionization (And that was a user of years and has been canceled because the process Ionization harmful Ealbaih), but I’m endowed mention them for more information Mesh

Important Note: There are several devices distributed in the room to be covered completely so that the distance between each device and last no more than 7.5 meters

Heat detector

Of his name .. It depends on the thermal sensor at high ambient temperature alarm works

Several devices must also distribute it in the room so that the distance between each device and the other no more than 5.5 meters

There are two types of it:

(A) the type of work at 60 ° Selezius .. and often is used in most applications

(B) Type Aamland 90 degrees Selezius .. and are used in the generator room (where the high temperature of 60 degrees is normal)

IMPORTANT: It is well known that the smoke detector is better than the heat detector, but must use the heat detector in places where there are fumes normally like car garage and kitchen

Multi Sensor

This type is a mixture of the two types of ex-that is, it has a smoke detector and heat detector … and this kind of expensive, but given the price and the effectiveness of the best.

Jaddaaa Important note: You must use the Multi Sensor replacement for the smoke detector only …. where if used in garages or kitchen (where the vapors normally resides) device will work when there is no fire

beam detector

Is used in the most heights of 4 to 5 meters

The most expensive species in the price

Consists of: transmitter and receiver, and the receiver is just a mirror reflecting the signal coming from the transmitter

The mechanism of action: When a fire cut fumes path between the T, R thereby acting the alarm

– There are two types of it

– Type should not exceed the distance between the T, R 50 meters

– The last type should not exceed the distance between them about 100 meters (most expensive)

– Is installing the machines at a height of 6 meters to 10 meters … and if height exceeds 10 meters device does not work when the fire

– Horizontal distance between each T, R and the T, R Elly after no more than 7 meters (after landscape).


The controller contains a unit FACP (shortcut Fire Alarm Control Panel).

FACP and consists of three parts (monitor – PCB – Battery)

– The monitor to display the choices and information

– The pcb electrical panel containing electronic devices

– Battery-powered system to extend until after Angtae current (where the fire alarm system is very important and should work even after Angtae electrical current)

The controller is divided into two basic types:

1. Type-called Addressable type: type and is characterized as the most expensive and has the potential to detect the fire place anywhere in any room where each room address and shows the room that the fire on the monitor and all the micro processor controls your address .

The addressable system consists of closed loop … See diagram:

We note here that the delivery closed loop and when the fire cut off the signal at a certain place and the micro processor can determine this place and thus determine the room exactly

2. Type-called conventional type: and is the type does not specify any room by the fire for example, if the system includes 50 rooms and a fire occurred in the room of them will not do I know any room of them by the fire occurred.

This system is characterized by cheap price.

Delivery method consists of several zones each zone includes several places

But the device can see the zone located in the sites by the fire … follow this format:

– Note the presence of 4 zones each zone includes several detectors devices

Also be at the end of each zone small resistance called end resistor working on the absorption of electrical signals on the body heat. (This is used a lot of resistance in the circuit, which uses open loop)

The cables used in the delivery of fire alarm

We use a custom type of cable called the fire resistance cable

And there are two types:

– Type I: Type bear to 950 degrees Seleucus (most expensive in price) and does not require the presence of pipe contained

– Type II: Type bear to 105 degrees Seleucus (cheaper in price), but requires the presence of a metal pipe contained (even bear the high temperature resulting from the fire)

Warning is divided into two types:

1- sound alarm only

2- sound and light alarm

And the sound is a bell or horn or sounder

And light-called (storbe light) and is light-like camera flash light

Other devices used in fire alarm systems

(1) manual call point or class break: (such as used in the subway carriages)

There is always in the streets and at the beginnings of the fire escape ladders

– And it is used for the operation of the alarm manually or open the doors manually

– Must not be less than the distance between each 2 manual call points from 30 meters

– Increase the MCB be from 1.2 meters to 1.35 meters at any level of the people.

Must distinguish between three common terms in the fire fighting systems and fire alarm systems

1- control module: its meaning and I watched the thing, and based on this observation do I adapted myself

2- monitor module: its meaning and I watched something and ask someone else to do due Based on this observation

Example: I am watching the water level in the reservoir associated with fire fighting systems and ask the worker to increase water

3- isolate module: is the process of separating and connecting to the network part of the fire alarm and so for maintenance and is also used in the separation of the network when an error occurs in electricity such as the short circuit (ie it looks like the circuit breaker used in electrical wiring.

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