Automatic Fire Alarm and Notification System for Security House
As a result of the design process, working documentation has been developed for equipping the security house with automatic fire alarm, powder fire extinguishing, and notification systems.
Design of Automatic Fire Alarm, Powder Fire Extinguishing and Notification System for Security House
The project provides for equipping the security house with automatic fire alarm, powder fire extinguishing and notification systems. The automatic fire alarm system is designed to detect fire sources by automatic and manual fire detectors and output control signals.
In ventilation chambers and other engineering equipment rooms where there are no combustible materials, as well as in rooms with wet processes, automatic fire alarm is not provided. The powder fire extinguishing system provides automatic fire suppression by volume in the diesel generator room.
The notification system provides audible alerting of people about fire in the security house.
All equipment used is certified for use in Russia.
All work on equipment installation and commissioning, cable laying, etc. must be performed in accordance with:
- This project
- Technical documentation for devices, equipment and materials
- Fire safety standards for buildings and equipment requiring automatic fire extinguishing and fire alarm protection
- Fire safety standards for fire extinguishing and alarm installations
- Standards for evacuation warning and control systems during fires in buildings
- Electrical Installation Rules
- Electrical Technical Devices building codes
CHARACTERISTICS OF PROTECTED PREMISES OF SECURITY HOUSE
The object includes a single-story house (security house) with a basement. Load-bearing structures of buildings are made of reinforced concrete. Premises are heated. There are no explosive premises or aggressive environment.
SYSTEM PURPOSE AND MAIN SOLUTIONS ADOPTED IN THE PROJECT
The fire alarm, notification systems and powder fire extinguishing automation are developed based on the Customer's assignment and current regulations on the basis of addressable analog equipment.
The automatic fire alarm system is designed for early detection of fire sources in protected premises and outputting signals, in case of fire:
- to activate type 1 people notification system about fire
- to shut down general ventilation
- "Fire" signal to fire department post.
For automatic fire detection, addressable analog smoke detectors and heat detectors are provided. Fire detectors contain a sensitive optical chamber and operate on the light scattering principle, operating voltage 15-28 V DC. Indicators and switches:
- 2 LEDs visible at an angle of up to 360°
- LEDs flash in normal mode and are fixed in "fire danger" state
- If necessary, for example in sleeping rooms, LED flashing can be disabled
- Two-decade switches for setting sensor addresses 01-99.
Fire detectors - heat detectors with fixed activation temperature. Smoke and heat detectors are mounted using mounting bases (special bases for concealed mounting are used in residential premises of the security house, providing concealed installation of detectors in false ceilings).
In cable tray laying areas, concealed installation of smoke fire detectors behind false ceilings is provided, with output of visual indicators to the external surface of the false ceiling. On evacuation routes, at each exit and on stairwells at a height of 1.5 m from the finished floor level, addressable manual fire call points are installed. Manual call points are included in ring-type loops. The distance inside buildings between manual call points does not exceed 50 m.
Control modules provide management of ventilation, air heating, notification system, powder fire extinguishing system, and also monitor the integrity of control cables connected to them. Monitoring modules provide monitoring (2 inputs), for organizing shutdown of automatic start of powder fire extinguishing by monitoring the status of magnetic contact sensors and monitoring local start buttons.
Addressable analog automatic fire detectors, manual fire detectors, control and monitoring modules are included in the alarm loops of the fire control panel. Type of alarm loop - ring.
Station Equipment:
Fire control panel provides:
- reliable and fast activation of fire detectors and determination of the exact location of fire occurrence
- adjustment of the activation threshold of each addressable analog detector depending on contamination with indication of limit state
- continuous diagnostics of end devices and alarm loops for break or short circuit detection
- appropriate sound and light signaling
- integration via interface line with automated workstation based on personal computer.
Three ring addressable fire alarm loops are connected to the fire control panel. Each loop can have up to 99 addressable detectors and 99 addressable modules. For all loops, monitoring for break and short circuit is provided. The fire control panel is located in the monitoring room on the 1st above-ground floor of the security house.
Powder Fire Extinguishing System
In accordance with standards for buildings and equipment requiring automatic fire extinguishing and fire alarm protection, the diesel generator room areas are subject to equipment with automatic fire extinguishing system.
Guided by the type of combustible substances, evaporation products of paints and requirements of standards, a powder fire extinguishing system was adopted as the technical solution for protecting the selected volume. For fire extinguishing in the diesel generator room, modular powder fire extinguishing installations based on powder fire extinguishing modules are most optimal.
The selected modules are intended for extinguishing fires of classes A (combustion of solid substances), B (combustion of liquid substances).
Control and monitoring equipment is built on the basis of addressable analog control and monitoring modules included in the alarm loops. The fire control panel is intended for collecting information about the status of smoke detectors in the diesel generator room, outputting control signals for control modules and displaying information about alarm situations on liquid crystal panels and automated workstation.
The fire control panel provides:
- monitoring of performance of addressable devices
- formation of command for automatic start of powder fire extinguishing when at least one detector located in the diesel generator room is activated
- automatic shutdown of automatic start mode when door opening sensors are activated and restoration of automatic start mode from fire control panel and workstation
- formation of command for activation of notification system
- formation of command for shutdown of ventilation and other technological equipment
- display of current information on liquid crystal indicator and workstation
- transmission of information to fire department post via telephone line.
Light and sound indicators "POWDER LEAVE" are installed inside the protected premises to signal that the control panel has registered FIRE notification in the powder fire extinguishing zone.
Light indicator "POWDER DO NOT ENTER" is installed next to the protected premises to signal powder discharge. Light indicator "AUTOMATION ENABLED" is installed next to the protected premises to signal automatic control of the powder fire extinguishing system.
Calculation of Fire Extinguishing Means for Powder System
Calculation of the number of powder fire extinguishing modules was performed in accordance with fire safety standards. The number of modules required for fire extinguishing by volume of the protected premises is determined by the formula considering the volume of the protected premises, volume protected by one module, and various coefficients.
Calculation results for the number of modules for fire extinguishing by area are summarized in the table.
Notification System
In accordance with standards, type 1 people notification is provided. An uninterruptible power supply provides power to sound indicators with 24V DC voltage.
Sound indicators provide alerting of people about fire with sound impulses and are located in places indicated on the equipment layout plans: - wall-mounted at height not less than 2.3m from finished floor level, and distance from indicator to ceiling not less than 150mm; Connection of indicators is performed without volume regulators and disconnect devices. Volume of indicators is fixed.
SYSTEM OPERATION ALGORITHM
System operation algorithm is provided by:
Standby Mode
- Automatic monitoring of addressable alarm loop for break or short circuit with transmission of all status information to fire control panel;
- Automatic monitoring for break and short circuit of connecting lines of alarm loops, communication lines between addressable control modules and general ventilation control panels.
- Automatic diagnostics of status of smoke detectors (dust accumulation status).
Fire Mode 1
Automatic detection of fire with decoding of fire source zone and system start in "Fire" mode:
- by activation of one or several smoke fire detectors;
- by activation of manual fire detectors.
Management of systems involved during fire:
- shutdown of general ventilation and air heating;
- activation of people notification system about fire;
- transmission of fire signal to fire department post via telephone line.
Fire Mode 2
Automatic detection of fire with provision of powder system start in diesel generator room and system start in "Fire" mode:
by activation of one or several smoke fire detectors.
Management of systems involved during fire:
- shutdown of general ventilation and air heating;
- activation of people notification system about fire;
- transmission of fire signal to fire department post via telephone line.
CABLE NETWORK
Fire alarm loop lines are executed:
As open wiring behind false ceilings with shielded cable in red PVC sheath in PVC corrugated pipes, metal trays using standard accessories and fasteners. Pipe fastening is performed with clip latches fixed using galvanized self-tapping screws in plastic dowels;
Laying of alarm loops from security house to central house is performed in underground conduit in pipes according to the "Internal Site Networks" project.
Control lines, power supply line, sound notification lines are executed with cable in red PVC sheath in PVC corrugated pipes using standard accessories and fasteners. Pipe fastening is performed with clip latches fixed using galvanized self-tapping screws in plastic dowels.
It is not allowed to lay alarm and connecting lines in the same cable channels with circuits with voltage over 60 V. With parallel open laying, the distance between wires and cables of fire alarm loops and connecting lines and power and lighting wires must be at least 0.25 m.
With parallel laying, the distance from cables to pipelines must be at least 100 mm. When crossing cables with pipelines, the distance between them must be at least 250 mm. When laying along the ceiling, the distance from cable wiring to walls and to the ceiling when laying along the wall parallel to the floor must be at least 100 mm. Laying of cables in risers to be performed in metal pipes. Passages of cables through walls and partitions are performed in sections of PVC pipes fixed in holes using cement mortar.
POWER SUPPLY
The fire alarm and powder fire extinguishing system in terms of power supply reliability belongs to consumers of I category of reliability and must have a power source corresponding to these requirements. Power supply of the powder fire extinguishing and notification system devices is carried out from low-current system power distribution boards 220V, 50Hz.
For the period of loss of AC power in the network, voltage 24V will be supplied to the systems from battery packs. Power supply of the notification system is provided from an uninterruptible power supply unit installed in the electrical room.