The fire alarm system is one of the most important MEP systems in any building.
If this system is not available in your project, you cannot hand it over to the civil defense.
The function of the fire alarm systems in projects can be summarized as follows:
1- Monitor
2- Alarm
3- Control
So we will know each one of these 3 functions
1- Monitor:
The main function of the fire alarm system is to monitor all areas & spaces in the project and to issue an early warning in case of a fire.
The announcement will be generated by detectors distributed across the different spaces in the project.
The distribution of the detectors and their types will depend on the type of the space, the height of the false ceiling “if exists”.
The distance between the detectors will depend on the area of the space and the detector’s coverage diameter.
The detector can be classified into the following types:
A- Smoke Detector
B- Heat Detector
C- Flame Detector
D- Multi-Sensor (Heat & Smoke)
E-Beam Detector
F- Fiber Optic Linear Heat Detection for Special Hazard Applications.
G- Manual break glass.
Each of these detectors has its own application; for example, I can’t use the smoke detector in the kitchen, a generator room, or any place with a lot of dust or fumes.
Also, I can’t use a heat or smoke detector in a paper factory, because if it senses smoke or heat, it means a fire is spreading, which is a disaster.
From the previous phrase, we can conclude that we will use another detector: the flame detector.
The purpose of the flame detector is to observe/sense the fire once it starts, not after it has spread.
We will use a flame detector in the generator room to trigger an immediate alarm at the onset of any fire.
We will use the beam detector in areas with high ceilings, such as lobbies with double-height ceilings, high-level atria, or hangars.
You need to know that each detector has a coverage area, which is the area that the detector can cover to sense heat or fire in that area.
The coverage area’s radius depends on the sensor type. For the smoke detector, its coverage area is almost 7.5m, but we consider it to be 5m to ensure overlap between the two adjacent detectors.
For the heat detector, its coverage area is almost 5.3m, but we take it to be almost 4.5m for the same purpose: to achieve an overlap.
Also, we can use the fire alarm system to monitor MEP equipment in the project using a monitor module (as shown in the next photo).
The monitor module is commonly installed on the firefighting Zone Control Valves. In the Fire Fighting Zone Control Valve, we will install 2 switches: the tamper switch and the flow switch. Both of these switches will be connected to a monitor module.
You can watch the next video to see the practical installation of both switches and the zone control valve, along with their connections to the fire alarm monitor modules.
The main purpose of these modules on the ZCV switches is to determine whether there’s a flow in the FF pipeline and whether the line is closed.
Also, we can use the monitor module to monitor other alarm panels, such as the FM200 panel, another Fire alarm panel, the Foam System Control Panel, or the Novec Control Panel.
Now we will talk about how the alarm will be generated in the Fire Alarm Control Panel.
The Alarm will be generated either automatically from one of the detectors or manually through a manual call point. When the fire alarm control panel senses an alarm, a notification message will appear on its screen, and at the same time, an alarm signal will appear on the workstation used for the fire alarm system’s graphics.
Moreover, in the presence of an alarm, a notification signal will be sent to the notification devices of the fire alarm system, such as audible devices (E.g., Sirens, Horns) or visible devices (e.g., flashers), or to both if they are available together.
Also, if you have a public address system, we will connect the fire alarm to the public address system to generate a voice evacuation message in case of fire.
Types of Fire-Alarm Systems
Fire alarm systems will be divided into four types: the first is the conventional system, the second is the addressable system, the third is the intelligent system, and the fourth is the wireless system.
Type 1: Conventional FA System:
In a conventional fire-alarm system, several call points and detectors are wired together, and signal wires go back to the control unit.
There are grouped call points and detectors. This grouping is called zones. These make it easier for the fire brigade and building management to determine the cause of the alarm.
A fire alarm control panel will indicate the appropriate zone by displaying an indicator lamp, text display, or both.
The more zones we divide a building into, the more accurately we can locate the alarm trigger.
Type 2: Addressable FA System:
The detection system of an Addressable System is the same as that of a Conventional System, with one crucial difference: each detector is assigned an address and will trigger an alarm that we can trace back to its point of origin.
The detection circuit of the FA system is wired as a loop. Many devices can be hooked up to the same loop, and each device can have 99 more.
To avoid a system-wide power outage, we will connect the loop to an isolation module, dividing the system into sections so that a short circuit or single fault will only cause the loss of part of the system.
Please note that, in both types of the FA system, Conventional and Addressable, we can’t consider their detectors to be intelligent.
Type 3: Intelligent FA System:
In this type of FA system, each detector has an embedded computer that reports to the Control Panel whether there is a fire or if the detector head needs cleaning.
Intelligent systems are more complex than other types of systems. They help stop false alarms.
By the way, an intelligent FA system can monitor large areas and spaces, as it has multiple panel versions with up to 8 loops.
Type 4: Non-wired or Wireless FA System:
Now, we reach the final type of FA system: the wireless system.
It’s very beneficial in areas where we can’t install containment to pull FA cables, for example, in ancient buildings where we can’t chip or modify the finishes of walls and ceilings.
The concept of its operation is that the signal between the panel and its devices will be transmitted via a radio network.
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