What Category of Fire Alarm System do I need?
Your Fire Risk Assessment should state what type of Fire Alarm System you require. Broadly speaking based on the risks within the building, building complexity, processes being undertaken, number of personnel. Interestingly whilst a Fire Alarm company can provide advice on the siting of fire detectors or recommendations in relation to upgrades or improvement the Fire Risk Assessor must decide what type of fire alarm system is required.
This could range from a category M system (Manual) through to L Systems (Life) which are automatic fire detection systems designed to protect life: L1, L2, L3, L4, L5.
Category L5: In a category L5 system certain areas within a building, defined by the fire system specification, are protected by automatic fire detection in order to reduce the risk to life. This category of system may also include manual fire detection.
Category L4: Is designed to offer protection to the escape routes from the building. The system should comprise Category M plus smoke detectors in corridors and stairways.
Category L3: Is intended to offer early enough notification of a fire to allow for evacuation before escape routes become smoke logged. Protection should be as for Category L4 with the addition of smoke or heat detectors in rooms opening onto escape routes.
Category L2: Objective are similar to Category L3, however additional protection is provided for rooms at higher risk. Protection should be as for Category L3 plus smoke detectors in specified rooms at high risk and documented within the specification.
Category L1: Is the highest category for the protection of life. This is intended to give the earliest notification of fire to allow maximum time for evacuation. Automatic and manual fire detection is installed throughout all areas of the building. Smoke detectors should be installed wherever possible to protect rooms in which people can be expected to be present. Protection of voids (such as ceiling voids and riser cupboards) should also be considered in line with the protection category and the Fire Risk Assessment.
Category P Systems
Category P2:This system is intended to provide early warning of fire in areas of high hazard, or to protect high risk property. Automatic fire detection should be installed in defined areas of a building
Category P1:The objective of a Category P1 system is to reduce to a minimum the time from the ignition of a fire to the arrival of the fire brigade. In a Category P1 System, fire detectors should be installed throughout a building. In a category P system, unless combined with Category M, it may be adequate for fire alarm signals simply to allow firefighting action to be taken, for example a signal to alert a responsible person to call the fire brigade.
Frequently Asked Questions
- There are an extensive range of Fire Alarm Systems on the market from different manufacturers all providing their own individual unique methods of detecting a fire.
The design of the Fire Alarm System after establishing what category the fire alarm should be needs to be undertaken by a qualified and competent person (designer). The level of protection needs also to be agreed with the owner/occupier of the building.
This discussion also identifies and justifies and variations to the design and these need to be clearly documented for the benefit of all parties.
The design must detail the detection and alarm zones as well as:
- Where the manual call points should be sited
- The location of point smoke and heat detectors in accordance with BS5839 design guidelines
- Siting of beam detectors (if required)
- Agreement of any other forms of detection within the building
- Specification relating to the cable of each circuit
- Specification to confirm the systems type and equipment i.e. addressable and non-addressable fire alarm systems
-
What is the difference between an Addressable and Non-Addressable fire alarm system?
Simply speaking there are two different types of fire alarm system: Addressable and Non-Addressable. Their differences are as follows:Addressable
A more comprehensive fire alarm system than a non-addressable fire alarm. The fire alarm panel allows you to ‘address’ it. It will tell you on the display whether the system has a fault, and where that fault may be. It will also on activation of the system allow the user to identify which call point or point detector has been activated in the building and its location. Addressable fire alarm systems are most suitable in large buildings or building of more complex design as it allows the building occupier to quickly identify the location of the activation without having to walk the whole building. This type of system will give the user more flexibility as it can be programmed to link with other systems in the building such as BMS shutdowns. It can also be linked to a monitoring station so any activation out of normal working hours can be quickly communicated to the emergency services or the building occupier.Non-Addressable
As the name states the system cannot be ‘addressed’ i.e. there is no LCD display on the panel that identifies the location of the call point or detector activation. Therefore, the building user is relying on the zonal chart which in accordance with BS5839 guidelines should be mounted next to the fire alarm panel. This type of system is more often installed in smaller premises such as shops, small retail units or buildings of simple layout and design.
Point Detection
The key to reliable, robust fire systems is having the right detector in the correct place. If the system is too sensitive it will generate unwanted alarms and won’t be regarded as giving accurate information, not sensitive enough and it won’t protect the building. Smoke and heat detectors can only detect fires once a certain amount of smoke or heat has reached the sensor. Therefore, it is important that the detector is correctly installed on a flat ceiling with no obstructions. The radius of detection for a smoke sensor is 7.5m and 5.3m for a heat detector. Detectors should be mounted a minimum of 0.5m from a wall. All smoke detectors that we supply conform to EN 54 – 7 and installed in accordance with BS5839 guidelines. We also install detectors in voids less than 800mm deep, unless on the basis of the Fire Risk Assessment it is thought that fire or smoke could spread extensively though the voids before detection, or unless the fire in the void is such to warrant protection.Laser Point Detection
If a particle of smoke (or dust) enters the chamber, light from the laser is scattered and the detector, using its patented algorithms, checks the nature of the scattered light to determine whether the source is dust or smoke. If a determination of smoke is made, the alarm is signalled.Beam Detection
Beam detection offers unique capabilities and limitations over point detection. They are particularly beneficial in wide open warehouses with big expansion of space. There are two basic types end to end detection which operate on the obscuration of light and end to end detection which has a separate transmitter and receiver unit. Once the beam is broken by rising particles of smoke and fumes the system will go into alarm.Wireless Detection
Wireless smoke alarm systems interconnect without the need to be hardwired and help to detect the presence of smoke, heat and carbon dioxide. Early detection of a fire can help to prevent loss of life and minimise damage to domestic and commercial buildings. Wireless smoke alarms are relatively easy to reposition if required. Most require a radio survey in order to measure signal strength between points before installation to ensure they will operate correctly. They are particularly suitable for historical buildings as no cabling is required or retrospective fitting in more challenging building complexes. They can however be more expensive to install then a conventional system and as they operate on batteries often require more ongoing maintenance than a hard-wired system.Open Area Smoke Detection
As an alternative to traditional beam detection open area smoke imaging detection (OSID) is a viable option. Key advantages to the OSID range of detection is that they are less sensitive to unwanted alarms caused by:- Building vibration and movement
- Periodic physical barriers i.e cherry pickers, high level ladders and forklift trucks
- Insects and birds
- Dirt, dust and steam
- Reflective and direct sunlight
Air Sampling (Aspirating Smoke Detection)
Aspirating Smoke Detection systems draw air samples continuously from a monitored area through a pipework system with pre-engineered holes drilled at predetermined locations along the pipe work run. The air is then sampled and analysed for smoke particles and the alarm will activate if smoke is detected as present. Some aspirating systems can now be remotely monitored through IP connectivity, maximising the benefits of this very early warning capability in reacting to a fire incident.Flame Detection
A flame detector is a type of sensor that can detect and respond to the presence of a flame. Responses to a detected flame depend on the installation, but can include sounding an alarm, deactivating a fuel line, and activating a fire suppression system. It is quite often used in specialised commercial manufacturing processes as an effective method of fire detection.Public Address and Voice Alarms
Before deciding on a Voice Activation alarm system the evacuation requirements of the building must be established:- Is the building to be evacuated all at once (one out all out)?
- Does the building require a phased evacuation plan?
Emergency Voice Communication System (EVCS)
An EVC System is a fixed, monitored and maintained, bidirectional, full duplex voice communication system to help assist the orderly evacuation of disabled or mobility impaired people and assist the fire service in terms of communication during an emergency.
Your fire alarm should be tested on a weekly basis. This is usually conducted by the responsible person on site or a nominated Fire Marshal. Each fire alarm call point should be tested on a weekly basis on rotation and a record of the test should be entered into the company’s fire logbook. This is a requirement of being compliant in accordance with The Regulatory Reform (Fire Safety) Order 2005 and BS5839 guidelines.
Our engineers can number your fire alarm call points so that when you conduct your weekly test you can enter the appropriate call point number against your records to demonstrate to any inspecting authority you have tested 100% of your building call points over a period of time.
The weekly testing procedure ensures that fire alarm signals operate correctly (if you are on a monitored system) and appropriate signals are clearly received by the monitoring station.
Most of our customers carry out the weekly test of their fire alarm at the same time to ensure there is no confusion for building users as to whether it is a test or genuine fire alarm activation. This should also form part of your company’s fire emergency strategy/emergency plan.
Our engineers can help demonstrate how to do this if you are unsure or new to the role of weekly testing. Furthermore, they carry a wide stock of fire alarm test keys for the different systems out in the market to ensure you remain compliant with your weekly testing schedule.
In accordance with The Regulatory Reform (Fire Safety) Order 2005 and BS5839 guidelines (Fire Alarm Systems) fire alarm should be serviced on an annual basis. It recommends that two inspections take place per annum by a competent and qualified person at a maximum of no more than 6 months apart.
At Firecom Systems Ltd all our engineers are BAFE trained and qualified to the highest industry standards. Therefore, when we award you with your inspection certification you can be reassured that your fire alarm system has not only been serviced correctly in accordance with BS5839 guidelines, but also by an experienced, professional, and qualified engineer.
At each inspection our engineer tests the fire alarm panel for functionality, battery loadings and calculations and 50% of the building detection system by using a smoke and heat pole (for heat detectors), to ensure the detection system is operating correctly and in accordance with industry guidelines.
On completion of the onsite testing our engineer will issue a certificate demonstrating your compliance with the standards and recording the performance of your fire alarm system. He will also make a record of any requirements or remedial works such as failed or slow to react detectors. It is recommended that smoke detectors are replaced around every ten years and again our team can discuss a rolling programme of upgrade works to ensure sensible budgeting costs of your life safety systems.