This article code alarm manual pdf multiple issues. Unsourced material may be challenged and removed.
An activated manual call point in Japan. Telephone jacks are visible beneath the open cover. Wireless Manual Call Point for temporary environments. Manual fire alarm activation requires human intervention, as distinct from automatic fire alarm activation such as that provided through the use of heat detectors and smoke detectors. Systems in completed buildings tend to be wired in and to include a control panel. Systems for use during construction can also be wireless or mechanical, however it is recommended by the Structural Timber Association in the UK that for timber-framed constructions, interconnecting wireless systems be used. After operation, most fire alarm pull stations must be restored to the ready position using a special tool or key in order for the panel to be reset.
Primitive manual stations, requiring only a single action or hand motion to activate, can be subject to unwanted activation by jarring or accidental contact. Early strategies to cope with this problem included requiring the operator to break a pane of glass to release an internal spring-operated mechanism. Manual pull stations that require two hand motions, such as lift up and pull down, or push in and pull down, have since replaced the break-glass and single-action models in many modern installations. In the past, pull stations controlled the entire system. These coded pull stations were much bigger than modern pulls and had a code wheel in them. The gears would turn a small wheel with a specific number of teeth, which determined the coding.
The teeth would push up on a contact, which would open and close a circuit, pulsing the code to the bells or horns. This code was used by building security to determine where the alarm was originating from. For example, consider a pull station in the fourth floor elevator lobby of an office building with a code of 5-3-1. When the station was pulled, the security officers in the building would look up 5-3-1 in a master list of codes. After finding the location of the pull, they would check to see if there is a real fire. If there was, they would evacuate the building and call the fire department. Turning it the other way and then activating the pull allows a silent test to be done in which the station’s mechanical parts are checked to ensure proper function.