Fire alarms manual

FIGURE M.2 Fire alarm manual pull station. 

In the event of fire within a building, the controller for each elevator should isolate all manually operated inputs and return automatically to the evacuation level, usually the ground floor. An output from the building fire alarm panel is hard wired to the elevator controller, giving the signal for a fire condition. The elevator remains disabled at the evacuation level and the car doors open. If a fire officer requires control of a elevator a key switch or break-glass unit should be used to re-activate the elevator. 

Simple switches that can be manually activated can be considered a fire alarm device. Models are used which normally require the use of positive force, i.e., to avoid accident and fraudulent trips. Fire alarm switches normally can only be reset by special tools in order to trace the source of the alarm, however sophisticated data reporting systems with addressable data collection may make this requirement obsolete. 

Wet or dry chemical fixed suppression systems are typically provided over the kitchen cooking appliances and in exhaust plenums and ducts. Activation means is afforded by fusible links located in the exhaust ducts/plenums usually rated at 232°C (450°F). Manual activation means should not be provided near the cooking area, but in the exit routes from the facility. The facility fire alarm should sound upon activation of the fixed suppression system and power or gas to the cooking appliances should be automatically shut off. The ventilation system should also be shut down by the activation of the fire alarm system. Protective caps should be provided on the suppression nozzles to prevent plugging from grease or cooking particulates. 

Remote manual starting is initiated from a remote point rather than from the fire alarm system or a pressure switch. The remote point should be at a constantly attended area. Pump running and trouble indicators should be provided at the remote start point. 

Class A and Class B laboratory units should have a manual fire alarm system installed and maintained in accordance with NFPA 72, National Fire Alarm Code. The fire alarm system, where provided, should be designed so that all personnel endangered by the fire event should be alerted. The fire alarm system should also alarm to an attended location to alert emergency responders or the public fire department. 

The presence of a trench/pipe system in Option B, used to remove rain accumulations, increases the risk that contaminated fire water might be inadvertently discharged into the sanitary sewer system. In order to reduce this risk, it is necessary to install a motorized valve in the drainage piping. This valve could be arranged to close automatically in the event of a fire through a signal from the fire alarm panel and manually as needed. It may also be desirable to use a valve which will automatically close in the event of loss of power. Alternatively, this valve could be normally closed and opened when needed. 

Powered ventilation systems in chemical warehouses are typically used for some flammable gas and liquid storage areas (see Gas and Vapor Control, Section 6.6). Heating and ventilation systems and powered roof exhaust systems can be arranged to shut down automatically upon receipt of a fire alarm signal so as not to interfere with sprinkler system operations due to airflow. Furthermore, these systems can also be arranged for manual starting and full exhaust by the fire department for smoke removal during search and rescue operations. 

A wide variety of sensing and initiating devices are available that can detect heat, smoke, radiant energy, and fire gas products. These devices should be selected based upon the type of fire anticipated. Additionally, sprinkler system water flow, activation of other extinguishing systems, and manual fire alarm pull stations can also be used to initiate an alarm signal. 

Only in exceptionally hazardous locations can an automatic fire alarm system be justified, but a manual system with break-glass buttons would be appropriate for all but the smallest installations and, since solvent fires can spread very rapidly, the manual system should be connected directly to the fire station. Standing orders should make it obligatory for the fire brigade to be called as soon as all but the most trivial fire is found in the solvent area. 

Every laboratory facility should be equipped with at least a manually activated alarm system, although an automatic system is preferable since it wiU continue to function when the facility is unoccupied. Automatic alarms are especially useful in academic institutions since there are break periods when the population of the campus is very low. In many cases, depending upon local code requirements and the occupancy classification, an automatic fire alarm system may be required rather than optional. Every component of a system should be approved by Underwriters Laboratories, the Factory Mutual System, or other nationally recognized accrediting and testing organizations. 

In a manual fire alarm system, the device used to activate the alarm in most cases is a pull box or pull station. The mechanism is very simple—puUing the switch either makes or breaks an electrical circuit which in turn causes an alarm to sound. As wiU be discussed more fiiUy in the next section, the alarm may sound only in the individual building, or the alarm could initiate a signal at a remote location as well. 

A signal indicating an emergency requiring an immediate action, such as an alarm for fire from a manual fire alarm box, a fire sprinkler system waterilow alarm, toxic or combustible gas detection, or an alarm fiom an automatic detection system. 

A switch provided on a fire alarm system that is manually activated to indicate a fire event (see Figure M.2). The switch is configured to conspicuously identify it as a fire alarm device and is usually fitted with a tamper device (break glass, rod, or cover) to discourage or prevent false activation. It sends a signal to a central monitoring station for notification of location and activation of alarms. 

All systems should receive a visual inspection each quarter. Test or inspect each antomatic system on an annual basis. Include all systems in the preventive maintenance plan. Test all snpervisory signal devices except valve tamper switches on a quarterly basis. Test valve tamper switches and water flow devices semiannually. Test duct detectors, electromechanical releasing devices, heat detectors, manual fire alarm boxes, and smoke detectors on a semiannual basis. Test occupant alarm notification devices to inclnde andible and visible devices at least annually. Maintain appropriate documentation on all tire-related system testing. 

Fire Service Features of Buildings and Fire Protection Systems Explains how fire service operations can be influenced by different building features and offers considerations for design professionals that can help facilitate these operations. The manual includes chapters and narratives on building and site design, sprinkler systans, standpipe systems, fire department connections, fire alarm and conununications systans, as weU as various firefighting systems (OSHA 3256— 2006). 

Figure 25.20 Manual fire alarm point, with hose reel. (Courtesy London Fire Brigade)...

The simplest form of fire alarms are manually operated devices such as gongs or bells. These are suitable only for the smallest premises where one of the devices can be heard throughout the whole building. 

Fire-detection devices are usually installed in systems which combine manually activated fire-alarm stations and audible and visual warning devices. They may also be connected to fire-suppression systems in some hazardous areas. 

Fire Alarm, Smoke Detection and Sprinkler Supervision Initiating Devices The hazardous occupancy must be provided with either a manual or automatic supervised fire detection and alarm system installed and connected to the ECS in accordance with NFPA 72A. (See also UFC 8004.2, UFC 5108, UFC 8003.1 and UFC 8003.3.)... 

Manual pull stations. NFPA Article 72A 5-8.1.2 requires the distribution of manual fire alarm pull stations throughout the protected area. 

Pre-entry fire safety checks of the premises prior to entry by members of the public >- Monitoring and reviewing the fire safety manual (log book) including false alarms and near miss fire events... 

The location of extinguishers >- The location of manual fire alarm call points >- The location of evacuation assembly points >- Fire action signage. 

The positions of fire alarm call points should be indicated with this type of sign particularly in areas where it may be necessary to identify the location of a manual alarm call point from some distance, e.g. in a large warehouse. 

In a large proportion of buildings a simple evacuation strategy will be adopted and on the operation of a manual call point or detection by an automatic fire detector, fire alarm sounders will provide warning and indicate the need for a full evacuation of the building. 

Zones - to support the above arrangements the building will need to be divided into a number of alarm zones in such a way that the fire alarm sounders reflect an operation of a manual call point within that area or a detector. 

The location of manually operated fire alarm call points and control equipment for the fire alarm... 

Buildings must contain a fire alarm or fire detection system that should automatically activate an alarm in the event of a fire. Install air conditioning, ducts, and any related equipment in accordance with NFPA 90A, Standard for Installation of Air Conditioning and Ventilating Systems. Ensure people can hear fire alarms over normal operational noise levels. Locate manual fire alarm stations near each exit. Inspect fire extinguishers at least monthly and ensure regular maintenance. Test fire alarm/detection systems once a quarter. Publish and enforce a Smoking Policy. Implement appropriate electrical safety policies and educate aU personnel about fire safety and response plans. 

Risk Reduction Factors Coutrol/ rator responses. Alarms, Control system response. Manual anti automatic ESD, Fire/gas detection system Sa/ety System Responses Relief valves. Depressurization system. Isolation systems, High reliability trips. Back-up systems... 

When dealing with an entire fire detection system that utilizes more than one type of detector, a Detonator Module greatly expands the flexibility and capability of the system. An individual Detonator Module can accept multiple inputs from UV and IR controllers, other Detonator Modules, manual alarm stations, heat sensors, smoke detectors or any contact closure device. In the event of a fire, any of these devices will cause the internal fire circuitry of the module to activate the detonator circuit, sound alarms, and identify the zone that detected the fire. When properly used, a Detonator Module will add only one millisecond to the total system response time. See Figure 8 for an illustration of a fire detection system with a Detonator Module. 

Stand alone fire or gas detection and alarm panels are normally provided in the main control facility for the installation. Recent trends also incorporate the transmittal of fire and gas alarms through the DCS into the main process alarm real time control panel. When alarm panels are located within a protected building, they should be located for easy access for emergency response personnel and proximity to manual electrical power shut off facilities. 

Alarms should be initialed by the local or main control facility for the location. Manual activation means should be provided for all emergency, fire, and toxic vapor alarm signals. Activation of fire suppression systems by automatic means should also indicate a facility alarm. Most fire and gas detection systems are also set to automatically activate alarms after confirmation and set points have been reached. Manual activation of field or plant alarm stations should activate the process or facility alarms. 

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