Module 3- Fire Alarm SystemComponents Fire Alarm System are: Detectors or Sensing circuits Smoke detector- Optical smoke detectors are used (Commercial buildings) Heat detector - Residential Buildings- Gas detector Notification System Sounders Siren Voi

Components Fire Alarm System are:
Detectors or Sensing circuits
Smoke detector- Optical smoke detectors are used (Commercial buildings)
Heat detector - Residential Buildings-
Gas detector
Notification System
Sounders
Siren
Voice message
Light Devices
Fire Alarm Control Panel (FACP)
MCP (Manual Call Point)
Line isolators
Battery back-up (2x12v=24v)

1. Fire alarm circuits Components Fire Alarm System are: Detectors or Sensing circuits Smoke detector- Optical smoke detectors are used (Commercial buildings) Heat detector - Residential Buildings- Gas detector Notification System Sounders Siren Voice message Light Devices Fire Alarm Control Panel (FACP) MCP (Manual Call Point) Line isolators Battery back-up (2x12v=24v) Building Automation Systems by Dr. Ramaprasad Poojary 1

2. Types of Fire alarm systems Building Automation Systems by Dr. Ramaprasad Poojary 2

3. Types of Alarm System

4. Conventional Fire Alarm System- Normal condition During Normal condition , predefined amount of current will flow back to FACP through EOL Resistor . Detectors are open-circuited and hence current can’t take that path. Building Automation Systems by Dr. Ramaprasad Poojary 6 FACP  Fire Alarm Control Panel EOL End of Line In the diagram, fire detectors are shown as capacitors. All the detectors are connected in parallel as shown above. Each detector has two terminals + ve and – ve .

5. Conventional Fire Alarm System- Trouble condition During Trouble condition wire which connects FACP to EOL breaks and current flowing through EOL back to FACP will be zero . FACP will know that there is a fault in the circuit. It can’t identify exact location as the devices are not addressable. Building Automation Systems by Dr. Ramaprasad Poojary 7

6. Conventional Fire Alarm System- Alarm condition When detectors get activated due to fire, they short-circuit the line and maximum current flow through the loop. Building Automation Systems by Dr. Ramaprasad Poojary 8

7. Addressable Fire Alarm System Building Automation Systems by Dr. Ramaprasad Poojary 9 D-Detectors A-Alarm

8. Addressable Fire Alarm System Building Automation Systems by Dr. Ramaprasad Poojary 10

9. Fire detectors are addressable Uniquely addressed detection devices Individual communications capability to each detection device Display of Individual device location Building Automation Systems by Dr. Ramaprasad Poojary 11

10. Addressing modes DIP switches – Dual in line package (Binary addressing) Rotary addressable devices, two switches are used to set the address. TENS switch & ONES switch. Below given switch can have a address range from 0 to 159. Most of the addressable devices will use one of above addressing modes. Building Automation Systems by Dr. Ramaprasad Poojary 12

11. Addressable detectors (Smoke, Heat, Gas/CO) are used to sense the fire and send a signal to notification system and FACP. Line Isolator: Use for disabling part of the loop in case a short-circuit occurs whilst normal operation is continued on remaining equipment Addressable Module with Relay Control : It allows controlling fire alarm devices featuring an activation input. Alarm devices can be activated through these relays. Addressable Bell Supervision Module: It allows us To connect two sounders which require external power Supply. Status of these devices also monitored. Rotary switches are used for addressing upto 159. Pushbutton (Manual Call Point): Addressable fire alarm call point. Fire Alarm Control Panel (FACP): Monitors the status & health condition of each device Flexible addressing Records the status info Building Automation Systems by Dr. Ramaprasad Poojary 13

12. Types of Fire Alarm Detectors Building Automation Systems by Dr. Ramaprasad Poojary 14 Manual Call Point

13. Optical Smoke Detectors FAP-DO420/FAP-420/FAH-420 is an Automatic fire detector from Bosch security. Advantages compared to other fire detectors: Operating voltage:15 V DC to 33 V DC Building Automation Systems by Dr. Ramaprasad Poojary 15

14. How optical smoke detector works? Building Automation Systems by Dr. Ramaprasad Poojary 16 An optical smoke alarm (also called photo-electric smoke alarm) works using the light scatter principle. The alarm contains a pulsed Infra red LED which pulses a beam of light into the sensor chamber every 10 seconds to check for smoke particles.

15. Heat detectors Used in Residential flats Heat detector can either work on a fixed temperature basis, where it will trigger an alarm if the temperature exceeds a pre-set value or they if it exceeds preset rate of change in temperature. Commonly Heat detectors work in a similar way to an electrical fuse, the detectors contain a eutectic alloy which is heat sensitive when a certain temperature is reached the alloy turns from a solid This causes a spring that is held under pressure to be released and complete an electric circuit, which sounds the alarm. Building Automation Systems by Dr. Ramaprasad Poojary 18 When temperature exceeds 135 o F When rate of change of temperature is more than 15 F / minute

16. How Fixed Temperature Heat Detectors Work? Alloy melts when temperature exceeds Preset value and spring releases and terminals make contact and current flows back to FACP indicating fire. Building Automation Systems by Dr. Ramaprasad Poojary 19 FACP  Fire Alarm Control Panel

17. XP95 A2S Heat Detector The XP95 Heat Detector monitors temperature by using a single thermistor which provides a count output proportional to the external air temperature.  The detectors are designed to be connected to a two wire loop circuit carrying both data and a 17V to 28V dc supply.

18. Fire Sprinkler Systems A sprinkler system is a network of pipes running through the ceiling of a building holding water under pressure. Defense against Out-of-control fire. small  glass  bulb full of a glycerin-based liquid designed to expand and shatter when it gets hot.  Various designs are available to meet the needs of residences, commercial buildings, restaurants, data centers, and other facilities. The right design of your fire sprinkler system is important for ensuring optimal performance and protection during a fire. Building Automation Systems by Dr. Ramaprasad Poojary 21

19. Benefits of Sprinkler systems Immediate identification and control of a developing fire. Sprinkler systems respond at all times, including periods of low occupancy. Control is generally instantaneous. Immediate alert. In conjunction with the building fire alarm system, automatic sprinkler systems will notify occupants and emergency response personnel of the developing fire. Reduced heat and smoke damage. Significantly less heat and smoke will be generated when the fire is extinguished at an early stage. Building Automation Systems by Dr. Ramaprasad Poojary 22

20. Wet Pipe Sprinklers The most common type of fire sprinkler system. A wet pipe system is easy to maintain and install. Wet pipe systems are filled with water with specific sprinkler head spacing. Each sprinkler head acts as its own heat detector. During a fire, the heat causes the core of the sprinkler head to burst discharging water. Not all the sprinkler heads are activated at once since each head is its own detector. The head will only burst when exposed to heat or broken off by physical contact. The advantage of this independence is that it can help to significantly reduce damage in the event of a false alarm since water will only be released from one head. It is not a surprise this type of system is still the most common application in the industry to this day.

21. Dry Pipe Systems A dry pipe sprinkler system is much like a wet pipe system except that the water is not contained within the pipes. Instead of water, the pipes in a dry system are pressurized by air or nitrogen. Water is still used to suppress a fire in these systems but is held back by a valve until the system is activated. A dry pipe system is a perfect application in environments that experience extreme cold where a wet pipe system would be subject to pipe freezing and impairments to the fire protection.

22. Pre-action Sprinkler Systems   A pre-action system is a dry pipe system where the water is held back by an electronically controlled valve that is connected to a fire detection system. Only after the fire detection system is activated will water enter the systems pipes and each sprinkler head is activated individually. A pre-action system is great for applications where accidental discharge of sprinklers would cause extensive damage like data centers and libraries.

23. Deluge Systems   A deluge sprinkler system is specifically designed for high-hazard areas in a building. In this system design, the pipes are dry and unpressurized, sprinkler heads are open, connection to a water source directly, and water is held back by a valve. When the system detects a fire, water is pumped through the systems pipes and is discharged through all the open heads flooding the affected area.