Week 11 Communication and Signal Systems PDF

COMMUNICATION AND SIGNAL SYSTEMS In general, all signal systems require a surveillance system to process information including transmitting it and a means of indicating the signal, either audibly, visually or permanently on hard copy. Types of Communication and Signal Systems: 1. Fire Detection Alar...

COMMUNICATION AND SIGNAL SYSTEMS In general, all signal systems require a surveillance system to process information including transmitting it and a means of indicating the signal, either audibly, visually or permanently on hard copy. Types of Communication and Signal Systems: 1. Fire Detection Alarm System 2. Building Security Systems – intruder detection alarm system, building access system & CCTV 3. Audio and Visual Telecommunication System – telephone, intercom, public tv 4. Time Equipment – clock and program equipment COMMUNICATION AND SIGNAL SYSTEMS FIRE DETECTION AND ALARM SYSTEMS detects products of combustion such as smoke, heat and light, and provide early occupant notification to allow the safe egress of the occupants. These systems use various methods to detect the products of combustion, including various heat and smoke detection techniques. They use audible and visual alarms to alert and warn building occupants of a fire. Parts of Fire Detection and Alarm System 1. Detectors 2. Control Unit or Panel 3. Alarm Devices 4. Wiring or Circuitry COMMUNICATION AND SIGNAL SYSTEMS FIRE DETECTION AND ALARM SYSTEMS DETECTORS There are 4 types of detectors: 1. Temperature Detectors (Heat Detectors) The most common is the temperature detector called the “Thermostat”. Detectors are rated by temperature and coverage. For example, in ordinary rooms, detectors are rated at 135F per 200 sqft. For kitchens, attics and basements where ambient temperature is higher, units are rated at 190F - 200F.  COMMUNICATION AND SIGNAL SYSTEMS FIRE DETECTION AND ALARM SYSTEMS DETECTORS There are 4 types of detectors: 1. Temperature Detectors (Heat Detectors) Types: a. Fixed Temperature Unit- triggers a set of contacts when a present temperature is reached. This unit is available in one-time non-renewable design that uses a low melting alloy fuse plug. b. Rate-of-Rise Unit- activates when the rate of ambient temperature differential exceeds a predetermined amount. This unit may be combined with the fixed temperature unit in a single housing such as in the case of an automatic resetting unit. COMMUNICATION AND SIGNAL SYSTEMS FIRE DETECTION AND ALARM SYSTEMS DETECTORS There are 4 types of detectors: 2. Photoelectric Detectors (Smoke Detector) These detectors react to the obscuration of a light beam by smoke. They are best applied where fires produce considerable quantities of smoke and gas, such as those caused by slow burning plastics. - A beam transmitter and beam receiver on opposite sides of a space detect when the beam is obscured - Response is slower - Require an unobstructed view - Recommended for high ceiling areas; spaces with medium to high velocity airflow; and closed areas with little airflow COMMUNICATION AND SIGNAL SYSTEMS FIRE DETECTION AND ALARM SYSTEMS DETECTORS There are 4 types of detectors: 3. Ionization Detectors These detectors operate by detecting ionized particles in the air. They do not detect fires producing heavy smoke but few particles such as alcohol and plastic fires. - Early warning type; instantaneous response once particles are detected - Used indoors with low airflow, large particles - Not used in areas where warm air collects, or particles are usually expected - Requires periodic cleaning and calibration COMMUNICATION AND SIGNAL SYSTEMS FIRE DETECTION AND ALARM SYSTEMS DETECTORS There are 4 types of detectors: 4. Flame Detectors These detectors are of two types; the infrared (IR) and Ultraviolet (UV) detectors. Applications are generally industrial and are highly sensitive. COMMUNICATION AND SIGNAL SYSTEMS FIRE DETECTION AND ALARM SYSTEMS DETECTORS There are 4 types of detectors: 4. Flame Detectors Types: a. Ultraviolet (UV) detectors - Long range, very sensitive - Reacts in milliseconds and responds to most types of fire - Used in highly flammable or explosive storages and work areas - UV detectors require rapid fire suppression and evacuation - Can detect UV radiation from walls and ceilings; can be blinded by thick black smoke COMMUNICATION AND SIGNAL SYSTEMS FIRE DETECTION AND ALARM SYSTEMS DETECTORS There are 4 types of detectors: 4. Flame Detectors Types: b. Infrared (IR) detectors - Detect rapid flaming combustion and CO2 production and reacts in seconds - Used in enclosed spaces such as sealed storage vaults - Have less range and lower sensitivity c. Combined UV/IR Detectors COMMUNICATION AND SIGNAL SYSTEMS FIRE DETECTION AND ALARM SYSTEMS MANUAL PULL STATION Lever like devices mounted on a wall in strategic places in the building that are connected to a building fire alarm control panel or directly to municipal or city fire alarm system. Alarm is sounded when the lever is pulled. EMERGENCY VOICE COMMUNICATION SYSTEM Provides preprogrammed recorded messages that offer direction, instructions, calming voice in an emergency situation. ALARM SYSTEM Alarm devices- usually audible such as bells, buzzers, gongs, strobes, chimes and horns. Most common is the a-c vibrating bell and a weatherproof external bell to alert neighbors and passersby. COMMUNICATION AND SIGNAL SYSTEMS FIRE DETECTION AND ALARM SYSTEMS ALARM SYSTEM Types of Fire Alarm Systems: a. MANUAL SYSTEM- uses visual detection and the alarm is triggered by hand Non- coded Manual Stations- the station are not identifiable at the control panel when it is manually triggered Coded Manual Stations- each manual station is coded, and this code is received at the control panel, processed and transmitted audibly on the system alarm devices b. AUTOMATIC SYSTEM- uses detectors to trigger the alarm system c. COMBINATION MANUAL AND AUTOMATIC SYSTEM COMMUNICATION AND SIGNAL SYSTEMS FIRE DETECTION AND ALARM SYSTEMS SPRINKLER ALARM SYSTEM Consist of sprinkler heads and network of pipes placed in horizontal pattern near the ceiling or wall and is designed to automatically dispense water on a fire. These are controlled through the Sprinkler Control Panel and interfaced with the pump controllers and FACP. COMMUNICATION AND SIGNAL SYSTEMS FIRE DETECTION AND ALARM SYSTEMS CONTROL UNIT PANEL - The function of the control panel is to energize the audible devices (bells, buzzers, gongs) upon receipt of a signal from the detector. - Other functions include shut-off of oil and gas lines, shut-off of attic fans to prevent fire spread, and turning off of lights. - Most units are serviced with an emergency standby battery. These can be interfaced with the BMS of the building COMMUNICATION AND SIGNAL SYSTEMS FIRE DETECTION AND ALARM SYSTEMS CONTROL UNIT PANEL Typical control functions in the Fire Alarm Panels are: 1. Non-coded Systems- these are continuous ringing evacuation type alarm devices, manual or automatic, which can be zoned and identifiable by means of an annunciator. COMMUNICATION AND SIGNAL SYSTEMS FIRE DETECTION AND ALARM SYSTEMS CONTROL UNIT PANEL Typical control functions in the Fire Alarm Panels are: 2. Master Coded Systems- this system is also called the common coded or fixed coded system and generates four rounds of code. When the code is set to ring the bells at 108 strokes per minute, the alarm is known as “march time” because of the rhythmic cadence. This alarm best applies in the rapid evacuation of a building and is frequently used in schools. COMMUNICATION AND SIGNAL SYSTEMS FIRE DETECTION AND ALARM SYSTEMS CONTROL UNIT PANEL Typical control functions in the Fire Alarm Panels are: 3. Zone Coded System- manual stations are grouped by circuit into zones which transmits to the panel and ring the zone’s code on the single stroke gong or chimes, thus immediately identifying the station. COMMUNICATION AND SIGNAL SYSTEMS FIRE DETECTION AND ALARM SYSTEMS CONTROL UNIT PANEL Typical control functions in the Fire Alarm Panels are: 4. Dual Coded Systems- this system is a combination of the non-coded and zone coded systems. When an alarm device generates, it initiates two different functions– an identifying coded alarm located in the maintenance office and a continuous ringing evacuation alarm for the whole building. COMMUNICATION AND SIGNAL SYSTEMS FIRE DETECTION AND ALARM SYSTEMS CONTROL UNIT PANEL Typical control functions in the Fire Alarm Panels are: 5. General and Selective Coded System- this is a fully coded system in which all manual devices are coded, and all automatic devices are arranged to trip code transmitters at the panel. 6. Pre-signal System- when it is desired to alert only key personnel, a system called pre-signaling is used, where it is also selectively coded. The personnel can immediately investigate and turn on the general alarm manually.