Fire Alarm Systems

Fire Detection And Alarm System :- The choice of fire alarm system depends on the building structure, the purpose and use of the building and current legislation. In new or altered buildings the enforcement body is the local building control, and the relevant guidance is explained in section new or altered buildings. All existing buildings except domestic premises are subject to The Regulatory Reform (Fire Safety) Order 2005 and the Responsible Person, as defined in the order, has to conduct a fire risk assessment.

 

This guidance contains brief descriptions of the major components which go to make up a fire alarm system. The points to be considered are intended to highlight the variables which can exist and need to be considered whilst designing and compiling a specification for component parts.

It is not the object of this note to consider the details of different circuit types or to discuss their relative merits.

Fire Alarm System :- We have provide cost effective Designers, Contractors, suppliers, Installation, Testing & Commissioning of Conventional Fire Alarm, Intelligent Fire Alarm, Fire Alarm Monitoring, Fire Detection, Fire Detection Systems, Fire Detection Devices, Flame Detection, Smoke Detection, Access control systems, public address systems. We are specialist in Fire Alarm Testing, Fire Alarm Training, Fire Alarm Inspection, Fire Alarm Maintenance , Fire Alarm Service , Fire Alarm Repairs in buildings in UP, Delhi, Okhla, New Delhi, NCR, Gurgaon, Noida, Faridabad, Ghaziabad, Kundli, Sonipat, Haryana, Uttar Pradesh & all over India.

Application

• • Day-care centres
• • Retails stores
• • Remote towers
• • Dormitories
• • Auditoriums
• • Gymnasiums
• • Restaurants
• • Movie theatres
• • Places of worship
• • Apartments / condominiums
• • Schools
• • Shopping malls
• • Strip malls
• • Museums
• • Nursing homes
• • Industrial facilities
• • Warehouses
• • Office buildings
• • Stadiums
• • Arenas
• • Correctional Facilities
• • Clean Rooms
• • Cold Storage
• • Nuclear Facilities
• • Portable Switch Rooms
• • Wind Power Generation
• • Industrial facilities
• • Data centres
• • Telecommunications
• • Generator rooms
• • Internet service providers
• • Mining
• • Museums
• • Warehouses
• • Office buildings
• • Auditoriums
• • Churches
• • High-rise buildings
• • Education
• • Manufacturing
• • Arenas
• • Stadiums
• • Cold storage
• • Malls
• • Airports
• • Stadiums
• • Prisons
• • High-security access areas
• • Museums
• • Churches
• • Mansions

Types of Fire Alarm Systems

All Fire Alarm Systems essentially operate on the same principle. If a detector detects smoke or heat or someone operates a break glass unit (manual break point), then alarm sounders operate to warn others in the building that there may be a fire and to evacuate. It may also incorporate remote signalling equipment which would alert the fire brigade via a central station.

• Fire Alarm Systems can be broken down into four categories :
• 1. Conventional
• 2. Analogue Addressable
• 3. Addressable
• 4. Wireless systems
• 5. Public address System
• 6. Access control system

Conventional Fire Alarm System

In a Conventional Fire Alarm System, a number of call points and detectors are wired to the Fire Alarm Control Panel in Zones. A Zone is a circuit and typically one would wire a circuit per floor or fire compartment. The Fire Alarm Control Panel has a number of Zone Lamps. The reason for having Zones is to give a rough idea as to where a fire has occurred. This is important for the fire brigade and of course for the building management. The accuracy of knowing where a fire has started is controlled by the number of Zones a Control Panel has and the number of circuits that have been wired within the building. The Control Panel is wired to a minimum of two sounder circuits which could contain bells, electronic sounders or other audible devices. Each circuit has an end of line device which is used for monitoring purposes.

Addressable Systems

The detection principle of an Addressable System is similar to a Conventional System except that the Control Panel can determine exactly which detector or call point has initiated the alarm. The detection circuit is wired as a loop and up to 99 devices may be connected to each loop. The detectors are essentially Conventional Detectors, with an address built in. The address in each detector is set by dil switches and the Control Panel is programmed to display the information required when that particular detector is operated. Additional Field Devices are available which may be wired to the loop for detection only i.e. it is possible to detect a normally open contact closing such as sprinkler flow switch, or a normally closed contact opening. Sounders are wired in a minimum of two sounder circuits exactly as a Conventional System. Loop Isolation Modules are available for fitting on to the detection loop/loops such that the loop is sectioned in order to ensure that a short circuit, or one fault will only cause the loss of a minimal part of the system.

Analogue Addressable Fire Alarm Systems

Analogue Addressable Fire Alarm Systems are often known as Intelligent Fire Alarm Systems. There are several different types of Analogue Systems available which are determined by the type of protocol which they use. The bulk of standard Analogue Detectors available are fairly stupid as the Detectors can only give output signals representing the value of detected phenomena. It is left up to the Control Unit to decide whether there is a fire, fault, pre-alarm or other. With a true Intelligent Analogue System each detector effectively incorporates its own computer which evaluates the environment around it, and communicates to the Control Panel whether there is a fire, fault or the detector head needs cleaning. Essentially Analogue Systems are far more complex and incorporate far more facilities than Conventional or Addressable Systems. Their primary purpose is to help prevent the occurrence of false alarms. With the Analogue Addressable System, up to 127 input devices i.e.: Smoke Detectors, Call Points, Heat Detectors, Contact Monitors and other interface devices may be wired to each detection loop. In addition to the 127 Input Devices, up to 32 Output Devices such as Loop Sounders, Relay Modules and Sounder Modules may be connected. Analogue Systems are available in 2, 4 and 8 loop versions which means large premises can be monitored from one single panel. Isolator units should be connected between sections of detectors as described for Addressable Systems.

Wireless Fire Alarm System

Wireless fire alarm systems are an effective alternative to traditional wired fire alarm systems for all applications. They utilise secure, licence-free radio communications to interconnect the sensors and devices (smoke detectors, call-points, etc.) with the controllers. It is a simple concept, which provides many unique benefits and is a full analogue addressable fire detection system without the need for cable.

Public address System

With the support of assiduous professionals, we are instrumental in manufacturing and supplying best quality Public Address Solutions. Our offered products owing to their precise functionality and long-range sound producing ability have made these a heavily demanded in the market. Their procurement is done from reliable vendor source that makes perfect blend of advanced technology and raw material for their fabrication. Moreover, these are offered to our clients at reasonable price tags.

Access control system

The system may help to protect staff and property, restrict access for unwanted guests and log time records of all activities of movements throughout your building.
Vinayak Fire Services provide a full range of products and systems, if you require a single door application or an integrated website programmed solution. Included in our services are access control software, connected to a range of readers and Identification readers. Additional devices are available such as magnetic strip, keypad proximity, biometric, card printers and smart card readers.

Benefits of Access Control Systems :-

• • Server compatibility
• • PC based system
• • Full Data management for the property
• • Allowing access for people entering and leaving
• • Integrated access control with alarm and CCTV systems
• • Standard readers
• • Smart card readers
• • Access system
• • Lift control
• • SQL database

System Design

Before starting, the designer will need to ensure that certain information is available. This may be given in the specification or it may have to be obtained by consultation. As well as the purchaser, there may be a requirement to consult with other interested parties

Points to consider

• • The type of system required i.e. L1, L2, L3 etc. and where appropriate, parts of the premises to be covered.
• • The action to be taken in the event of fire
• • Whether other occupants of a multi occupancy building will be affected
• • Whether other work is to be done at the same time. If so then consultation with other contractors may be required.
• • A Method of calling the Fire Brigade
• • Whether the type of occupants or activity in the building will require a greater provision of Manual Call Points than normal
• • A likely attendance time of the Fire Brigade

Control of Indicating Panels

Control and indicating equipment performs three principal functions, namely :

Benefits of Access Control Systems :-

• • Automatic monitoring and control of circuits external to the equipment, such as fire detection and fire alarm device circuits and supply of power to these circuits
• • Indication of fire signals, fault signals and their location
• • Manual control to facilitate actions such as testing, disablement of devices, triggering of fire signals, silencing of audible fire warnings and resetting the system after a fire signal

Panels are fully specified in British Standards. This requires that circuits are monitored continuously and that both audible and visual indication is provided for fault and fire alarm conditions. Further requirements include that alarm sounders may only be silenced manually, after which the control panel must provide audible and visual signals until the system is reset. Silencing of alarm sounders must not prevent the alarm being raised in other zones. It should be noted that the standards require all fault/alarm indicator lamps to be in duplicate or a single lamp with audible signal of lamp failure. Control and indicating panels may include facilities for operation of ancillary services such as fixed fire extinguishing, door closing etc.
The equipment should normally be sited in an area of low fire risk and on the ground floor by the entrance used by the Fire and Rescue Service and preferably viewable from outside of the building. It should be located in an area common to all building users and where automatic detection is in use, the Control Panel should be in a protected area. An alarm sounder should be sited next to the Control Unit, but not too near the telephone position. A suitable zone chart of the building should normally be installed adjacent to the Control Panel.

Points to consider :-

• • Number of zones required
• • Surface or flush mounting
• • Maximum alarm load per alarm zone
• • Automatic system, compliance with British Standard
• • Manual system compliance with British Standard
• • Maximum current per detector zone
• • Maximum detectors per zone
• • Open, closed or fault monitored system
• • Single or two stage alarms
• • Provision for connection to remote manned centre
• • Provision for conduit and wiring compatible with building conduit and wiring system
• • Provision for operation of ancillary services

Detector Heads

These can be divided into four main types Heat detectors, Smoke detectors, Carbon Monoxide detectors and Multi sensors detectors.

Heat sensitive point detectors

Point detectors can again be subdivided to a further two types.

• 1. Fixed temperature which will operate when it is exposed to a pre-determined temperature. Normally fixed temperature detectors employ a fusible alloy element which must be replaced after the detector has operated. Different temperature rated elements are available to take account of varying ambient air temperatures.
• 2. The second type operates on the rate of temperature rise. The rate of rise temperature detector may also include a fusible element for fixed temperature operation.

Both types are suitable for inclusion in open, closed or line monitored systems.

Linear detectors
These can take the form of a heat sensitive cable which will operate, at a predetermined temperature, as an open circuit device. Melting of the cable insulation provides a short-circuit between conductors. After operation the destroyed length of cable must be replaced. Linear detectors may be used in large areas such as warehouses. Alternative types of linear detector exist including the heat pneumatic operating on the rate of rise principle.

Points to consider :-

• • Open, closed, fault monitored circuits
• • Temperature setting for fixed temperature fusible elements
• • Spare fusible elements
• • Surface or flush mountings
• • Temperature setting for fusible elements in the rate of rise detection., if included
• • Mounting height
• • Spacing to manufacturer's recommendations
• • Rate of rise detectors located in positions where abnormal increase in temperature is likely, e.g. space heating equipment, industrial processes

Smoke Detectors

There are three basic types operating by ionization, light scattering and light obscuring.

There are three basic types operating by ionization, light scattering and light obscuring.

CO fire detectors are electronic detectors used to indicate the outbreak of fire by sensing the level of carbon monoxide in the air. Carbon monoxide, usually known by its chemical formula CO, is a poisonous gas produced by combustion. They are not the same as CO detectors used for home safety which are used to protect residents against carbon monoxide produced by incomplete combustion in appliances such as gas fires or boilers.

Multi sensor detector

This detector combines inputs from optical and heat sensors and processes them using a sophisticated algorithm. When polled by the control panel it returns an analogue count which is determined by combined responses from both optical and heat sensors. They are designed to be sensitive to a wide range of fires and may be used in place of an ionisation detector in many instances.

Manual Call Points

A Break Glass Call Point is a device which enables personnel to raise the alarm by breaking the frangible element on the fascia. They should be mounted 1.4m from the floor and sited where they can be easily seen. Manual Call Points should be sited on the floor landings of stairways and at exits to open air. It should be noted that Call Points should be fitted on the floor side of an access door to a staircase so the floor of origin is indicated at the Control Panel. Extra points should be sited, where necessary, so that the greatest travel distance from any point in the building to the nearest call point does not exceed 30m. A greater number of Call Points may be needed in high risk areas or if the occupants are likely to be slow in movement. Flameproof call points are available, also handle operated points for use in areas where broken glass may cause a hazard.

Points to consider

• • Open circuit, closed circuit, fault monitored circuit
• • Surface, flush mounting
• • Weatherproof, internal location
• • Spare breakable material
• • Contact rating suitable for load under alarm conditions
• • Special call points for flameproof or special hazard areas
• • Hammer for call points with breakable front plates

Power Units

Two power supplies are required i.e. mains and battery and these are normally built into the Fire Alarm Control Panel. Standby batteries must allow the system to operate without mains for 24 hours longer than the building is likely to be unoccupied and then support the sounders for an additional half hour. If the mains supply is supported by an emergency generator then six hours standby plus half an hour alarm load is sufficient. All modern Fire Alarm Systems are 24 volts. On the medium and larger sized Fire Alarm Systems, the standby batteries will often not fit within the Control Panel. Where standby batteries are contained within a separate housing, then this housing must be as close as possible to the main Fire Alarm Control Panel. If the power supply or battery housing is located more than 10 metres from the main Fire Alarm Control Panel then serious volt drop problems can arise. Standby batteries are invariably of the sealed lead acid variety. Use of Nickel Cadmium Batteries is not cost effective and automotive batteries must not be fitted.

Points to consider

• • System voltage
• • Battery charger output
• • Battery capacity
• • Indication of battery and/or mains supply failure
• • Secondary battery exclusive to fire protection system
• • Where system voltage exceeds extra-low voltage compliance

Self-Contained Fire Alarm Units

These units normally incorporate break glass contact, fire alarm sounder, battery and charger. The units are suitable for small hotels, shops, guest houses etc. A single sounder can be expected to give a 3 hour alarm. This reduces to one hour when three additional 6 bells are installed. Self-contained units incorporating smoke detectors are also available, They normally include visual and audible indicators of the circuit and power supply faults.

Points to consider

• • Open, closed or fault monitored circuit
• • Smoke detectors to be incorporated
• • Operating voltage
• • Number of additional bells
• • Resistance of connecting cables
• • Spare glasses for contact
• • Mains supply connection for unit
• • Spare cartridge fuses