Building safety is due not only to passive fire products; when it comes to emergency conditions, active life-safety systems also play a major role. It is the combination of both active and passive fire products/systems by which we can ensure the building’s safety.
There are many active systems that work as standalone and as interconnected networks with multiple other systems to provide guidance/evacuation/emergency alarms/alerts/safety announcements and also building fire protection.
Fire detection and alarm systems are simple input and output type life-safety systems that not only detect fire and give an alarm but also interface with many other systems in the building to monitor the status of third-party systems or to control/signal the third-party systems in case of emergencies.
It is fire detection and alarm system which:
- signals the smoke control system in order to control the spread of smoke by activating extract fans and by making smoke compartments
- signals the doors in the building to be automatically closed or opened in emergency conditions
- signals the emergency lights and exit signs to be activated for the safe passage out
- automatically activates the voice evacuation system to provide clear pre-recorded, programmed and live evacuation instructions for the people in the building, etc.
It is an intelligent system that can also trigger or send information to local Fire & Rescue and Civil Defence teams in case of emergencies when interfaced with them. This should be the basic requirement in every region to have direct connectivity with local bodies in order to save lives and have proper public safety from emergency fire conditions.
In order to get the above-mentioned and similar benefits from the fire detection and alarm system installed, there should be a sequence of operations (cause and effect matrix) always programmed.
Fire detection and alarm systems should not only be installed in buildings but also in warehouses, villas, nurseries, restaurants, showrooms, boutiques, enclosed parking, cold storage, etc. to ensure proper public safety.
Various signals in fire detection and alarm system (FDAS)
If not the common public, at least trained personnel should be available and be aware of the FDAS signals, and it is very important to understand which signal is for what so that proper actions can be taken in those situations without escalating it to a panic situation.
Trouble, supervisory, alarm, and control are four basic fire detection and alarm signal categories:
- A trouble signal means that there is an operational issue in any device with the Fire Alarm and Detection System.
- A supervisory signal is an issue with one of the systems connected and monitored by the fire alarm system mostly using input modules (Monitor modules).
- There are two types of alarm signals: automatic and manual. The signals initiated from detectors are automatic alarm signals and signals initiated from manual call points are referred to as manual alarm signals.
When we have an alarm signal, it means there is a fire condition that needs immediate action. Sometimes there can also be false alarms that should be verified, and if so, the alarm signal should be reset to its normal stage manually when required.
A control signal is a signal sent by the fire detection and alarm system itself for taking any action pre-programmed as per the sequence of operation and also manual signals.
We can only have these signals when the proper sequence of operation is programmed.
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Different types of fire detection and alarm systems
Conventional type is a limited-feature system that works by dividing the building into detection zones, with detectors and call points in each zone, hardwired on dedicated circuits to the control panel. There may be multiple detectors in a single zone. A separate two-core, fire-protected cable for each alarm sounder or bell is needed because they are wired to different loops.
If a detector is activated, the panel identifies the circuit that contains the activated device and so indicates the zone from which the alarm has originated, but the area then has to be manually searched to pinpoint the individual device.
Addressable type is designed for large premises and more complex networked systems have increased flexibility, intelligence, speed of identification and scope of control.
Here different types of initiating devices are wired in one or more loops around the premises, with each detector or call point having its own unique address so that we can know the exact pinpoint location of the device activated.
Wireless type is flexible and much quicker to install, wireless or battery-powered radio-linked, fire alarm systems provide just as much protection as conventional wired systems and are useful when wired installations are not suitable.
Devices
Automatic alarm initiating devices/detectors: smoke, heat, carbon monoxide, multi sensors, beam type, video image, flame, gas, aspirating smoke detectors, etc.
Manual devices: break glass/pull station/manual call point.
Alarm notification devices: sirens/bells/sounders/horns, flashers/strobes/beacons.
Input modules: monitors third-party systems like smoke dampers, fire dampers, fan control, smoke doors, fire doors, etc.
Output modules: Controls/signals third-party systems like voice evacuation, emergency lighting, elevators, doors, HVAC, smoke control, fire protection, etc.
Isolator modules are used to protect the system against short circuits on the signalling line circuit loop.
We can have a healthy fire alarm and detection system in our building when we are bound to follow all the requirements of the code, standards, and local regulations.
Standards
We should all know what is standard and why it is so important. The standards are a set of instructions/guidelines for product manufacturers and their designers. Standards specify the proper construction and performance of the product and give proper instructions to a designer to have a proper design and guidelines to a manufacturer in the process of manufacturing.
Every device in the fire detection and alarm system has an individual standard. There are many different bodies making standards and standard families around the world like EN 54 series of standards from European Norms, UL Standards from Underwriter Laboratories, ISO 7240 series of standards, LPS, BS, FM, IEC and there are also country/region specific standards.
Now don’t think the standard is only for the product designers and manufacturer; it is in real need for the end users of the product, and end users in fire detection and alarm systems are the common public. So, to have all the early warnings, public announcements, public safety and many more benefits of the fire detection and alarm system it is not enough only to have the system installed in our building but also before having that product installed, we should also ensure the product meets specific standards.
Like there are bodies making standards, there are also bodies testing those products according to their standards and certifying them accordingly. Now how do we trust those testing and certification bodies? We can simply trust them when they are accredited according to ISO/IEC 17025 for Testing and ISO/IEC 17065 for Certification. These certification bodies also have a process of marking/labelling the products they have certified, and in order to provide trust in the product we can always check for the marking and certification of the product.
Images supplied by Author / Contributor.
Codes
The way there are bodies making standards similarly there are bodies developing codes like NFPA, ASTM, IBC, IFC and there are many countries having their own codes developed. When these codes incorporate any product-specific standards and if any of these codes are regulated by the government of that particular region then it becomes a Law and we have to follow the product standards and guidelines from that particular code.
Now what is code? Code will serve as generally accepted guidelines for design, fabrication, construction, installation and maintenance.
Code gives us the guidelines on how to construct the product, how to select the product, how to and where to install the product and it not only gives guidelines up to the installation and handing over of the project but it also gives guidelines on how to maintain the product by timely inspections and maintenance.
Every building, irrelevant of its size, should have a fire detection and alarm system installed and along with it there should always be trained personnel available in every building to take care of the system, who should have knowledge of all the signals of the system and should know what actions to be taken in different scenarios of emergencies.
For more information, email faheemuddin.mohammed@emirateslaboratory.com
About the Author
Mohammed Faheemuddin is a Fire and Life Safety Engineer with experience in the design, programming, testing and commissioning of fire detection and alarm systems, voice evacuation, and emergency lighting/central battery systems along with exposure to various international codes, standards, technical specification and other regional regulations. He is a Certification Specialist in Dubai Civil Defense’s Emirates Safety Laboratory.
