FIRE ALARM SYSTEMS

Fire Alarm Systems encompass a wide range of complexity and applications. From the smallest single zone systems to the largest multiplex, multiple site integrated systems, fire alarm systems have evolved into highly reliable and technologically advanced Life Safety Systems. G.A. Sibley has kept pace with this change and can offer you the best in fire alarm systems. As a Simplex Fire Alarm equipment distributor we can supply all of your fire alarm needs, whether you need replacement parts such as bells, horns, pull stations, detectors, etc. or complete Fire Alarm Systems.


Requirements for Fire Alarm Systems

The National (Canadian) or Provincial Building and/or Fire Code determines the application of the fire alarm systems based upon the use of the building (occupancy type) and the number of persons that could theoretically use the building (occupancy load). The following is a guideline ONLY, please check with your local codes and regulations.

Occupancy (group)/Type Division # Building Example Occupancy Load
A Assembly
Occupancy
1
2
-
-
3
4
Theatres
Restaurants
Schools
Daycare
Arenas
Grandstands
See General Guidelines
150
40
40
See General Guidelines
See General Guidelines
B Institutional
Occupancy
1
2
Prisons and Jails
Health Care Facilities
10
10
C Residential
Occupancy
Apartments and
Condiminiums
Motels and Hotels
More than
1 family
See General Guidelines
F Industrial
Occupancy
1
2&3
High Hazard
Med & Low Hazard
25
See General Guidelines

 

General Guidelines

In addition to the above, any building including business and mercantile occupancies are required to have a fire alarm system if:

Type of Fire Alarm System Required

Type Description Occupancy
Single Stage Single (Bell or Horn)
Indicates Evacuation
Industrial (Division 1)
All Others
Two Stage Signal (Bell or Horn)
Indicates: 1 Alert
2 Evacuation
Institutional (Some exceptions
for Buildings 3 Stories or Less)
Emergency Voice Speakers Supply Tone
and Voice Communications
All Buildings over 36m
Healthcare Above Third Story

 

Size of Fire Alarm System

Input Circuits:

Typically, the size of a fire alarm system is defined by the grouping and annuciation of initialing devices as zones (inputs) connected to the control panel. Alternate or other zoning may be required due to egress, fire compartmentalization, or engineering practice.

Output Circuits:

The size of the control panel is also determined by the number of output circuits provided in the panel. This includes:

Signal Circuits

Used to control audible and/or visual devices which provide notification of an alarm condition to the building occupants.

The number of signal circuits is determined by:

Ancillary Circuits

Used to control devices and equipment within a building which assist life safety. This includes:

Note: Although not defined as ancillary devices, magnetic locks used for security access control must be interconnected to the fire alarm system so that they cannot prevent occupants from exiting a building upon alarm.

Auxiliary Circuits

Used to provide a signal to the fire department (or central station) upon alarm. An auxiliary (monitored) circuit must be provided if the building is:

Wiring Requirements

The following information is a summary of general wiring requirements. Please refer to the local Electrical Code and product installation documentation for specific guidance for your installation.

General requirements

All system wiring shall be installed in a metallic raceway or incorporated in an acceptable cable assembly. All fire alarm system wiring must be independent of any other wiring. Fire alarm systems shall be supplied from separate circuits connected to the load side of the main service disconnect after any transformation and used solely for the supply of energy to the system. Over current devices and disconnect means in the supply circuits shall be contained in a separate enclosure and shall be clearly identified and the enclosure shall be coloured red.

Circuit Types

Detection and signaling circuits are supervised for opens, shorts, and ground fault. Supervised circuits can be either:

Wire Selection

Most manufacturers recommend 18AWG, 16AWG, or 14AWG, solid copper, 2 conductor wire cable for detection and signaling circuits. Refer to the control panel installation manual for determination of wire gauge.

Detection Circuits

The maximum number of smoke detectors per circuit listed in device section. Maximum wire run is typically 5000ft.

Signal Circuits

Maximum number of devices per circuit and maximum wire run determined by device current draw, as listed in device section. Maximum signal current per circuit is listed in control panel section.

Fire Alarm Control Panels

There is a tremendous variety of Fire Alarm Control Panels available on the market today. The advancement and cost reduction in microprocessor based systems has led to a proliferation of these systems. The following is a typical panel common to most "simple" fire alarm applications. Most panels are designed with a standard number of zones , typically two, four, eight, sixteen, thirty-two, and sixty-four zones. Most modern panels allow for the expansion of fire alarm systems with the addition of modular zone "cards". For example an eight zone panel can be purchased with the capability to be expanded to thirty-two zones. By installing additional zone circuit boards into the panel, the system can be expanded. A typical panel with be equipped with the following features:

Smoke Detectors

Smoke detectors provide the earliest possible automatic detection of a fire and are therefore essential for life safety. Smoke detectors sample the composition of air in a building area and initial an alarm when the products of combustion are identified. There are two methods used to accomplish this. Ionization detectors use the principle that a fire produces particles with characteristic electrical charges that can be detected. Photoelectric detectors use the principle that smoke particles from a fire are visible and will obstruct light. Smoke detectors are manufactured either as a single unit or as a unit which allows a head to be removed from a base to facilitate cleaning and calibration after installation.

Codes and Standards

Codes and standards do not distinguish between the use of ionization or photoelectric smoke detectors: however, photoelectric detectors are found to be more effective in sensing products of combustion that have cooled as they move away from their source.

Smoke detectors must be installed in every corridor in:

And must be installed:

Further:

As defined as a fire detector under the code, devices must be installed in: Storage, Service, and Janitor rooms as well as Elevator, Dumbwaiter, and Laundry shafts.

Coverage and Spacing

Each detector is ULC listed for a specific spacing, based on flat ceiling with a height less than 9ft. (3m). Detectors are to be mounted at least 24in. (600mm) from any obstruction and at least 35in. (900mm) from a supply air diffuser. Typical area coverage of smoke detectors is 900 sq.ft. (100 sq.m.). Maximum spacing of smoke detectors is 30ft. (10m). Refer to CAN/ULC-S524 for guidance whenever an application differs from above.

Heat Detectors

Although heat detectors are defined (with Smoke Detectors) as fire detectors under the code, heat detectors activate much later than smoke detectors because they rely upon the accumulation of heat within an area to activate. Heat detectors should be used only to provide detection where environmental factors restrict the use of smoke detectors or building construction provides sufficient fire containment. The basic operation of heat detectors is described as follows:

Fixed Temperature

Fixed temperature type heat detectors are activated by room or area temperature reaching a preset temperature threshold (usually 135oF/58oC).

Rate of Rise

Rate of rise type heat detectors are activated by a rise in temperature increase greater than 15oF/9oC per minute (resettable).

Codes and Standards

Heat detectors:

Must be installed in every room in portions of a building classified as:

Exception for sprinklers:

Heat detectors are not required to be installed where an automatic sprinkler system is installed throughout the floor area and the sprinkler trim devices (flow and supervisory switches) are connected to the fire alarm.

Further:

As defined as a fire detector under the code, devices must be installed in: Storage, Service, and Janitor rooms as well as Elevator, Dumbwaiter, and Laundry shafts.

Coverage and Spacing

Each detector is ULC listed for a specific spacing, based on flat ceilings and a height less than 9ft. (3m). Typically, fixed temperature type heat detectors are rated for 15ft. (4.6m) spacing while rate of rise heat detectors are rated for 50ft. (16.6m) spacing. Detectors are to be mounted at least 24in. (600mm) from any obstruction and at least 35in. (900mm) from a supply air diffuser. Refer to CAN4/ULCS524 for guidance whenever an application differs from above.

Air Duct Smoke Detectors

Product Description

Duct smoke detectors provide control of supply air fan units and dampers within a building to prevent the movement of smoke throughout a building in the event of fire. Duct smoke detectors consist of a smoke detectors head and base, enclosed in a sealed housing, with a tube placed inside the duct to provide a sample of the circulating air to the detector. The detector is usually installed with relay control of the supply air fan unit by either a relay provided in the control panel, or in the duct smoke detector housing. Air sampling tubes are installed across the duct at least 2 duct widths away from any bend or equipment. Air sampling tubes may be ordered from 13" to 97" in length.

Codes and Standards

Duct smoke detectors are required in any building equipping a fire alarm system and are installed downstream of any supply air fan unit to prevent the circulation of smoke; where the air handling system serves more than one storey, or one suite, or more than one zone or fire compartment in a Healthcare facility.

Manual Pull Stations

Product Description

Manual pull stations provide a ready means for activation of the fire alarm system by persons within a building upon the discovery of a fire. The basic operation if manual pull stations is described as follows:

Number of stages - Single or two stage. A single stage pull station places the fire alarm system into full alarm upon activation. A two stage pull station places the fire alarm into a prealarm mode (alert) upon activation. The system may go into full alarm upon confirmation from another initiating device or authorized personnel. Alternately, the alert condition may be canceled and the system reset by authorized personnel, usually within a specific time frame.

Number of actions - Single action stations allow activation of the lever in one action. Double action stations require two distinct movements to activate the pull station. This helps to prevent accidental alarms.

Restriction - Break rod stations have a plastic or glass rod placed across the lever that must be broken to activate an alarm. A variety of housings are also available to protect the pull station and prevent false alarms.

Codes and Standards

Pull stations must be red, readily visible and must be installed in every floor area near every required exit. In addition, they must be mounted on the wall not less than 47in. (1200mm) and not more than 55in. (1400mm) in height.

Bells and Horns

Product description

ULC listed bells or horns may be used to provide one or two stage signaling for the fire alarm system. Typically, signal devices are listed for over 90dB at 10ft. and a signal intensity requirement of at least 15 dB above background noise is easily achieved under ideal conditions using standard devices and spacing. Using this guideline, 20ft. spacing between signal devices is recommended however, consideration must be given to installation factors which will require either closer device spacing or a "louder" signal device. These include: