Design Basis for Fire Detection & Alarm System

In this article, we will discuss the basic building blocks of the Fire Detection & Alarm System (FDAS). Before selecting a fire detection system, it is a must to have the information related to process and engineering and the key areas for its installations as well.

An overview of the fire detection and alarm system is given below.

Fire Detection & Alarm System

Applicable Codes and Standards

The below-mentioned codes and standards provide the guidelines for the installation of the fire detection and alarm system. These standards need to be followed for designing or implementing a Fire Detection & Alarm System.

Code & StandardDescription
NFPA 72: 2019National Fire Alarm Code
IS 2189:2008Code of Practice for selection, installation, and maintenance of Automatic Fire Detection and Alarm System
IS 2175:1988Heat-sensitive fire detectors for use in automatic fire alarm systems.
IS 1881:1998Indoor installation of sounding system
BS EN 50288 7:2005Multi-element metallic cables used in analog and digital communication and control, Part 7- Sectional specification for instrumentation and control cables

Selection Criteria of FDAS Components

Type Of Detector/ DeviceArea/ Environmental Conditions
Fire Alarm Control PanelControl Rooms
Repeater PanelControl Rooms, Substations, And Remote Locations
GUI With PCControl Room
Multisense DetectorsRack Rooms & Cable Cellars
Heat DetectorsCompressor Areas, Oil & Gas Storage Areas, Store Rooms
Beam-Type Smoke DetectorsOil & Gas Storage Areas,
Chlorine Gas DetectorIn Chlorine House
H2S Gas DetectorIn Sulphur Plant Or In Plants Where Sulphur Is Present
Hydrogen Gas DetectorsBattery Room And Hydrogen Plant
Manual Call PointAll Areas In Industry
Ex-Proof Manual Call PointHazardous Areas
Linear Heat Sensing CableCable Cellars
Control Module / Monitor ModuleRequired For Actuating Other Devices Like Hooter & Other Systems

Fire Alarm Control Panel (FACP)

Fire Alarm Control Panel (FACP)

Fire Alarm Control Panel(FACP) is the main control panel of any Fire & Gas detection System. The controller is present in the FACP. The FACP has a display, various keys, or a keypad for functions like reset, acknowledge, and silence buttons. Whenever any device connected to the FACP actuates or goes faulty, the FACP senses that faulty signal, and then it displays and buzzes the alarm on the FACP panel. Accordingly, FACP actuates the hooters and flashlights. All loops going into the field are connected to the FACP.

Fire Detection & Alarm System- Fire Alarm Repeater Panel

Whenever there is a long distance between the FACP and the F&G devices, a repeater panel is used. The repeater panel repeats the signals by increasing the signal quality and then sends it to the connected network. The repeater panel has a display and various keys or a keypad.

Graphical User Interface (GUI) with Workstation

Graphical User Interface (GUI) is software for accessing the programming part of the F&G system. Every device in the loop is controlled by the main controller’s programming. This programming is done using the GUI. Also, an audio-visual representation of the whole F&G of the plant is shown in this GUI. Whenever any device goes into an alarm state or goes faulty, the operator can easily see the status of that device on the GUI.

Fire Detection & Alarm System- Multi Sense Detector

 Multi Sense Detector

The Multi Sense detector detects both the smoke and the heat. They have a thermistor for detecting heat.  The detectors are loop powered and hence they have their own unique address. Each detector has a microprocessor circuit that detects errors or alarms or any other faults.

Fire Detection & Alarm System-Manual Call Point (MCP)

Manual Call Point (MCP)

The Manual Call Point is the device that actuates on pressing. We generally use them in case of emergency. Whenever an MCP is pressed, an alarm is generated, and accordingly, action is taken for rescuing the person. MCP is the most important F&G device in case of an emergency. The MCPs are of two types. One has a glass and the other is a resettable type. In glass type MCP, every time after actuation, the glass needs replacement as glass breaks after actuation.


Hooter starts as soon as it receives a command from the FACP. In case of actuation of any F&G device, the hooter is supposed to hoot to alert nearby people. The hooters are installed in almost every area.

Monitor Module

The Monitor module monitors the condition of all the devices. Whenever any device goes into fault mode or alarm, the monitor module detects it. The monitor module continuously detects the voltage levels in the loop. When the monitor module senses any change in the voltage (voltage is having imposed digital signal), it actuates an appropriate device.

Control Module

The control module is a kind of relay. This module actuates devices like hooters and flashing lights.

Chlorine, H2S, and Hydrogen Gas Detectors

Chlorine, H2S and Hydrogen Gas Detectors

Chlorine, H2S, and Hydrogen gas detectors are used to detect the respective gas leakages in the plant.

Fire Detection & Alarm SystemBeam Type Smoke Detectors

The Beam detectors are installed on the roof of certain buildings or in certain areas at the top. The height is generally more than 10 meters. The area between the beam-type smoke detector should be clear.

Fire Detection & Alarm System- Heat Detector

Fire Detection & Alarm System- Heat Detector

The heat detectors are used to detect the heat. Heat detectors are of two types. One actuates when the temperature goes above a certain temperature. While the other type of heat detector gives an alarm when the rate of temperature increase is high above a defined level.

Fault Isolator Module

The Fault Isolator Module(FIM) immediately isolates the loop devices for maintenance jobs or during a failure. Fault Isolator Module is provided in every loop for every 20 devices or detectors. FIM is like an intermediate terminal block to isolate a part of the loop for checking or maintenance purposes.

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