Manual Call Points

Manual call points Does not rely on instrumentation Likely to be slow False alarms possible Outdoors and at key locations indoors... 

Manually operated alarm call points should be provided in all parts of a building where people may be present, and should be located so that no one need walk for more than 30 m firom any position within the premises in order to give an alarm. A breakglass manual call point is shown in Fig. 14.49. They should be located on exit routes and, in particular, on the floor landings of staircases and exits to the street. They should be fixed at a height of 1.4 m above the floor at easily accessible, well illuminated and conspicuous positions. 

All of these are very well visualized in cause and effect diagram which is presented in a tabular matrix form. Normally, various causes such as manual call point, heat (say) rate of rise, flame detection (say) infrared, etc., whereas effect gives the details like audible alarm, audio visual alarm in DCS, etc. Generally these documents need approval (from competent authority). 

Manual - systems that allow for the detection of fire by people will be provided with suitable manual call points. The call points must ... 

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. 

Manual call points according to safety plot plan, accessible, signed, functioning... 

Manually operated alarm call points should be provided ih all parts of a building where people may be present, and should be located so that no one need walk for more than 30 m from any position within the premises in order to give an alarm. 

Automatic detection of fire is possible with heat and smoke detectors. These are usually installed on the ceilings and at the top of stair wells of buildings because heat and smoke rise. Smoke detectors tend to give a faster response than heat detectors, but whether manual or automatic call points are used, should be determined by their suitability for the particular installation. They should be able to discriminate between a fire and the normal environment in which they are to be installed. 

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. 

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

Manual Alarm Call Points (MACs) allow an operator to initiate the emergency response system, regardless of the response of the automatic instrumentation. They can be used for any type of emergency. The typical MAC is of the open contact Break Glass type, suitable for Division 1 locations. MACs should be covered with a guard to prevent inadvertent alarm activation. They should be clearly visible and labeled and easily operable by personnel wearing personal protective equipment (PPE) such as gloves. 

Historically, the first and most important capacitance method is the vibrating capacitor approach implemented by Lord Kelvin in 1897. In this technique (now called the Kelvin probe), the reference plate moves relative to the sample surface at some constant frequency and tlie capacitance changes as tlie interelectrode separation changes. An AC current thus flows in the external circuit. Upon reduction of the electric field to zero, the AC current is also reduced to zero. Originally, Kelvin detected the zero point manually using his quadrant electrometer. Nowadays, there are many elegant and sensitive versions of this technique. A piezoceramic foil can be used to vibrate the reference plate. To minimize noise and maximize sensitivity, a phase-locked... 

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