# شرح لنظام الانذار ضد الحريق



## mwya (1 أكتوبر 2016)

شرح لنظام الانذار ضد الحريق :

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 

___________________________________________________

Fire alarm system-design secrets


Addressable system design secrets:
· Distance between Smoke Detector mustn’t exceed 10 m to avoid dead area between detectors
· Distance between heat Detector mustn’t exceed 7 m to avoid dead area between detectors
· Fire detector must be mounted at least one meter from any forced air inlet.
· Ramps at car parking must be covered by heat detectors
· Voice evacuation located at escape stair must be in a separate loop.
· Fire fighter telephone must be located at elevator lobbies & pump rooms.
· Each fire loop must have 20% spare capacity.
· Access control system ( ACS ), elevator, Door holder,Public address system ( PA ), exhaust fan’s, Air Handling Units( AHU’S ) connected to fire alarm system via control module ( CM )
· Fire fighting system( FM200, CO2, Sprinkler system( flow switch & Tamper switch ) ) connected to fire alarm system via monitor module ( MM ).
· Alarm bell located at 2200mm above finished floor level.
Posted by Engineer at 4:57:00 PM 
Email This
BlogThis!
Share to Twitter
Share to Facebook
Share to Pinterest


----------

