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Fire detection and alarm products placed on the market within the European Union must, following Regulation (EU) No 305/2011, conform to the European harmonized technical standard EN 54 Fire Detection and Fire Alarm Systems. EN 54 part 11 is the section of the mandatory standard relating to manual call points.
A bypass capacitor is often used to decouple a subcircuit from AC signals or voltage spikes on a power supply or other line. A bypass capacitor can shunt energy from those signals, or transients, past the subcircuit to be decoupled, right to the return path. For a power supply line, a bypass capacitor from the supply voltage line to the power ...
Variable Speed Fire Pump Controllers were invented and released with a UL Listing for fire pump service in 2003 by Master Control Systems, Inc. [1] [2] Paragraph 10.5.5 in the 2003 edition of NFPA-20 recognized Variable Speed as an accepted method for operating the fire pump. Then in the NFPA-20 2007 edition, section 10.10 was added to clarify ...
A short piece of fire hose, usually 10 to 20 feet (6.1 m) long, of large diameter, greater than 2.5 inches (64 mm) and as large as 6 inches (150 mm), used to move water from a fire hydrant to the fire engine, when the fire apparatus is parked close to the hydrant.
The ferroresonant transformer, ferroresonant regulator or constant-voltage transformer is a type of saturating transformer used as a voltage regulator. These transformers use a tank circuit composed of a high-voltage resonant winding and a capacitor to produce a nearly constant average output voltage with a varying input current or varying load.
A switched-mode power supply also exploits this effect, but the energy is not dissipated to heat and is instead used to pump a packet of additional charge into a capacitor, in order to supply power to a load. When the inductive load is a relay, the flyback diode can noticeably delay the release of the relay by keeping the coil current flowing ...
Coded panels were the earliest type of central fire alarm control, and were made during the 1800s to the 1970s. A coded panel is similar in many ways to a modern conventional panel (described below), except each zone was connected to its own code wheel, which, depending on the way the panel was set up, would either do sets of four rounds of code until the initiating pull station was reset ...
A fire alarm box, fire alarm call box, or fire alarm pull box is a device used for notifying a fire department of a fire or a fire alarm activation. Typically installed on street corners or on the outside of commercial buildings in urban areas, they were the main means of summoning firefighters before the general availability of telephones.