The light scattering and light obscuring detectors both, detect visible smoke. The ionization detector and light scattering detector are normally each a single unit suitable for BESA conduit box mounting. In some models the smoke detector head is attached to the main body by a bayonet fixing for easy removal for maintenance or replacement. It should be noted that some detectors are suitable for two-wire circuits whereas others require three or four wire connections. Smoke detectors require a continuous power supply. Under quiescent conditions they draw a current of some 100 micro amps, and under alarm conditions, some 45 milliamps. This needs to be borne in mind when sizing the power supply. Smoke detectors generally operate on 24 d.c. Refer to British Standard Codes of Practice and manufacturers literature for information regarding the positioning of smoke detectors. Detectors are not suitable for positioning in kitchens, near fireplaces or areas with excessive exhaust fumes, or within 2m of air supply ducts or diffusers. Carbon Monoxide detector There are three basic types operating by ionization, light scattering and light obscuring. Ionisation One method of connection used to be a direct monitored line which used to be called a PW (dedicated private wire/line) eg to the fire service, which is not used very often these days. These generally contain two chambers. One is used as a reference to compensate for changes in ambient temperature, humidity or pressure. The second contains a radioactive source, usually alpha particle, which ionizes the air passing through the chamber where a current flows between two electrodes. When any of the products of combustion enters the chamber the current flow decreases. This drop is used to initiate an alarm. Light obscuring

Vented batteries should be examined by a person with relevant competence and should be topped up if necessary Fire detection and fire alarm systems for buildings. Code of practice for the design, installation and maintenance of fire detection and fire alarm systems in dwellings Fixed temperature which will operate when it is exposed to a pre-determined temperature. Normally fixed temperature detectors employ a fusible alloy element which must be replaced after the detector has operated. Different temperature rated elements are available to take account of varying ambient air temperatures. Signals from the optical smoke chamber and temperature sensor are independent, and represent the smoke level and air temperature respectively in the vicinity of the detector; the detector’s micro controller processes both signals. The temperature signal processing extracts only rate of rise information for combination with the smoke signal. The detector will not respond to slow increases in temperature but a large sudden change can cause an alarm without presence of smoke, if sustained for 20 seconds. The processing algorithms in the multi-sensor incorporate drift compensation. Points to consider

Alarm Sounders

The inspection and servicing should be undertaken by organisations with the appropriate competence. This can be assured by the use of organisations that are third party certificated, by a UKAS accredited certification body, specifically to carry out inspection and servicing of fire detection and fire alarm systems. This information is provided for the general guidance of fire detection and fire alarm system users. As it is a summary, it omits much of the information included in BS5839 part 1. It is therefore not intended to be a replacement for the detailed recommendations included within British Standard. Routine testing by the user Manual control to facilitate actions such as testing, disablement of devices, triggering of fire signals, silencing of audible fire warnings and resetting the system after a fire signal

Altering the environment – you might be tempted to put headphones in whilst the testing is being carried out, unfortunately, you shouldn’t do this. Electronic solid state sounders with mono or multi tone output normally in the range of 800 – 1000 Hz. As this is labour-intensive servicing, it is recommended that the work can be spread over two or more service visits during each twelve-month period Fire alarm testing should be carried out weekly, preferably on the same day and at the same time to remain consistent. The British Standard to do with the testing of a fire alarm system is BS 5839-6: 2019 “Fire detection and fire alarm systems for buildings”. In section 25.2 it states that all fire alarm systems in commercial premises need to be tested weekly. It’s crucial in the fire detection strategy of any building that you need to make sure your system is working efficiently and correctly. If an emergency occurs and your fire alarm system isn’t working, the results could be fatal, there’ll be no early detection of fires or sounders for safe evacuations which could lead to injuries, death and plenty of damage. How to Test My Call Points Using Keys Tags: alarm panel servicing frequencies BS 5839-1:2013 bs5839 BS5839 part 1 2017 BS5839 part 6 2013 BS5839 pt 6:2013 BS5839 pt1:2017 fire alarm panel maintenance how to install fire alarm panel maintaining a fire alarm system servicing of fire alarm panels servicing of fire alarm systemsThe type of system required i.e. L1, L2, L3 etc and where appropriate, parts of the premises to be covered. Sirens ranging widely in size from 0.17kw to 11kW generally operating in the frequency range of 400 – 800 Hz. Proven time served reliability with a feature set that offers significant user benefits to the customer Fire detection and alarm systems for buildings. Code of practice for the design, installation, commissioning and maintenance of emergency voice communication systems White manual call points: Since those don’t indicate a single function, there should be additional signage telling you what this particular call point does. However, there’s one thing white manual call points can’t be used for and that’s to call the fire services

Testing the same call point – you have to test a different call point every week, otherwise the tests won’t be even. Each use of an emergency account should be reviewed. The use of an emergency account may be valid, or it might indicate a malicious act. Unacceptable use needs to be recorded and acted upon. Frequent use may indicate problems with the normal user authentication mechanism. This regular monitoring of pre–staged emergency accounts should also include exercising some of them to ensure that they do work, and that their use can be detected. This is similar to testing fire alarms, to be sure that they will work in a real emergency. Cleaning Up After Account Usage If you happen to uncover a fire at work, sounding the fire alarm using a manual call point is the fastest way to get your colleagues’ attention and prompt them to get to safety. If the fire isn’t big enough to have triggered the automatic fire detection system, your proactive actions could help put the flames under control before the fire has had the chance to spread. Sealed and taped to the side of a monitor in a clinical area—visible to many so it will be obvious when it is missing or damaged, or There’s always something new you can learn to improve your fire safety knowledge and today we’ll look at yet another key element of your fire detection system – the manual call points (MCP) used to activate your fire alarm. From what they actually do and where to find them to using and testing them correctly – here’s everything you need to know about fire alarm call points.A policy has been devised by the Department of Communities and Local Government for Fire and Rescue Services which is Policies for Dealing with Unwanted Fire Signals from Automatic Fire Alarms. Statutory Regulations CO fire detectors are electronic detectors used to indicate the outbreak of fire by sensing the level of carbon monoxide in the air. Carbon monoxide, usually known by its chemical formula CO, is a poisonous gas produced by combustion. They are not the same as CO detectors used for home safety which are used to protect residents against carbon monoxide produced by incomplete combustion in appliances such as gas fires or boilers.

Every automatic fire detector should be examined and functionally tested. This includes, but is not limited to; smoke detectors, resettable heat detectors, optical beam smoke detectors, aspirating fire detection systems, carbon monoxide fire detectors and flame detectors Forgetting to document – providing written evidence of which call point you tested and when you tested it is important for the authorities and health and safety officials. Auditing should be enabled if available, to log details of the account usage and details of the work carried out while using the account. Some systems may recognize emergency accounts and raise the system auditing level or increase audit logging of only the emergency accounts. Whether the type of occupants or activity in the building will require a greater provision of Manual Call Points than normalFire detection and fire alarm systems. Control and indicating equipment has replaced BS 5839-4:1988