Fire Alarm System

Discussion in 'The Projects Forum' started by nitin.bharat, Oct 13, 2007.

  1. nitin.bharat

    Thread Starter Member

    Sep 6, 2007
    10
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    i want to make Fire Alarm System using senors( like smoke detector, heat detector, etc) for a building. Does any body have idea about that.there will be so many sensors how to deal with them. which sensor is giving warning. how to make connection.

    if any body has seen Fire Alarm System please describe it.
    waiting for your ideas...
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    You might look up the properties of the individual sensors - heat and smoke, for instance. Google probably has a few thousand topics available.

    Part of the problem with home-brewed alarms is the liability issue (at least in the U.S.). If your alarm ever fails to work, many lawyers will cluster around to make you pay for the error.
     
  3. nitin.bharat

    Thread Starter Member

    Sep 6, 2007
    10
    0
    firstly i should have general idea. then i will study sensors. how the whole system will be built.
     
  4. cumesoftware

    Senior Member

    Apr 27, 2007
    1,330
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    That's what lawers do... I pray for a good start.:D:D:D
     
  5. nitin.bharat

    Thread Starter Member

    Sep 6, 2007
    10
    0
    can any one give me Synopsis on fire alarm system.
    :confused:
     
  6. SgtWookie

    Expert

    Jul 17, 2007
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    1,728
  7. GS3

    Senior Member

    Sep 21, 2007
    408
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    I have a Tandy Radio Shack model 49-475 Home Alarm System which has only one fire zone (i.e. it does not say where the fire is, only identifies it as a fire alarm). The central unit is microprocessor controlled and quite sophisticated. All the fire sensors are connected in parallel plus the system has a test function which checks the integrity of the wires. The fire/smoke sensors are NO and close a switch when an alarm occurs but if a wire was broken the alarm condition would not register so the central unit checks the integrity of the wiring periodically. By closing a relay beyond the last sensor it can detect the integrity of the alarm wiring. If the wiring is not intact then the system registers a wiring fault alarm. The circuit thus requires four wires: two for the N.O. alarm loop and another two for the test function.
     
  8. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    I have been installing commercial fire alarm and life-safety systems for about a dozen years, on and off. I humbly suggest that you peruse NFPA 72: http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=72

    This will tell where to put sensor devices and warning appliences, what kind to put there, and how the system should react to sensor inputs.

    If you wish to know which sensor is in the alarm state, an "analog addressable system" must be used. You already have the link for Google, provided by our favorite Jar-Head (Sgt.Wookie), above.
     
  9. GS3

    Senior Member

    Sep 21, 2007
    408
    35
    Well, I am not sure what you want to know or to what level of detail but in general terms you would have a central control unit with a display and you would have the remote sensors. Depending on the specific needs the central unit can be anything from the most simple to the most sophisticated and the same goes for the remote sensors. Maybe if you tell us more about what you are trying to acomplish we could be more spoecific. Also, bear in mind that regulations are different in each jurisdiction so it makes a difference on whether you are just trying to gain some general understanding or you are actually trying to design a real system.
     
  10. nitin.bharat

    Thread Starter Member

    Sep 6, 2007
    10
    0
    I have to submit synopsis if chosen then we will work on that project.
    i saw the fire alarm image sent by you. but unable to under stand how it works how sensors are connected.
     
  11. RiJoRI

    Well-Known Member

    Aug 15, 2007
    536
    26
    I program the micros used in commercial burglary and fire alarm systems. I work for Honeywell -- we used to be Ademco. There are MANY requirements for making alarm systems -- not only the NFPA, but also UL, and SIA. The system must be near-perfect, because many locales are fining the home or business owner for false alarms. We started building a new system (basically ground-up as you would be doing). Despite having experienced people working on the hardware and software, it has been almost 5 years, and we have not gone to beta testing yet; although I will admit creeping featurism is playing a large part, as well as UL-864 requirements.

    It does not sound like buying a system from a well-established company is an option, so, I wish you good luck!

    --Rich
     
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