Thursday, September 29, 2016

Fire alarm system

Codes & standard
·         NFPA ( National Fire Protection Association ) 
·         BS 5839 ( British Standard )
·         VDS ( Germany)
 
System types:
·         Addressable  system
·         Conventional system
·         Wireless  system
Addressable  System Components:
-          Smoke Detector
·         2 types (optical smoke detector & ionization smoke detector ( not used now) )
·         Located at
§  all rooms, halls, storage areas, basements, attics, elevator, shafts, enclosed stairways, dumbwaiter shafts, and chutes.
§  Cover area with raduis ( r= 5m )  toatal area equal πr square = 80 meter square.
-          Heat detector
·         2 types ( fixed heat detector & rate of rise heat detector)
·         Located at:
§  generator room, Kitchen & Boiler room.
§  Cover area with radius ( r= 4m )  total area equal πr square = 50 meter square.
-          Multi-sensor ( smoke & heat ) detector
·         Locate at: ( electrical, communication, mechanical & control )rooms
-          Flame detector
·         2 types ( Ulta-Violet UV & Infra Red)
·         Locate at:
§  petrol station & workshop nearest to source of flame
-          Beam detector
·         Consists of transmitter  ( T ) and receiver ( R ), Located at wide open plan areas
-          Gas detector
·         Located at Kitchen nearest to source of gas
-          Carbon Monoxide detector
·         Located at place that may be contain co gas as garage area
-          Duct smoke detector
·         Located at HVAC duct at return & supply
-          Manual station
·         Locate at:
§  Entry/Exit doors, at corridors every 61 m at height not less than 1.1 m and not more than 1.37 above floor level as per NFPA requirements
-          Fault Isolator
·         Located very 20 device inside fire loop to make loop continue working in case of any short circuit in the loop
-          Control module
·         Used to control exhaust fan’s,Air Handling Units ( AHU’S),Elevators...............
-          Monitor Module
·         Used to monitor fIre fighting system as ( FM200, CO2..........)
-          Fire  alarm repeater panel ( FARP)
·         Used to show faults as in main fire alarm panel but no action can be taken from FARP, Located at any floor beside counter areas
-          Types of alarms
·         May be  audio / audio with strobe / strobe
-          Alarm devices
·         Bells
·         Horn speaker ( outdoor )
·         Evacuation with Strobe light ( Flasher )
-          Types of cable used in fire alarm systems
·         Fire retardant cable till 105  ͦC 
·         Fire resistance cable [ 750 ͦ ,950 ͦ,1050 ͦC]
·         Fire  alarm cable must be Copper conductor ( retardant or resistance )with cross section
·         2 ( 1pair ) x 1.5 mm( cable cross section )
·         Cable cross section depend on number of device ,detector & loop length  
-          Types of conduits  used in fire alarm systems
·         PVC Conduits used in embedded installation 
·         EMT Conduits used in Exposed installation
·         UPVC Conduits used in outdoor installation

Fire Alarm Control Panel ( FACP ), Workstation & batteries




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