Fire detection

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Fire detection

• MIT 40

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Fire

• Basically, a fire is a chemical reaction in which
  a carbon based material (fuel), mixes with oxygen
  and is heated to a point where flammable vapors
  are produced.
• These vapors can then come in contact with
  something that is hot enough to cause vapor
  ignition, and a resulting fire

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Fire evolution 1

• The typical accidental fire begins as a slow
  growth, smoldering process which may last from a
  few minutes to several hours.
• The duration of this "incipient" period is
  dependent on a variety of factors including fuel
  type, its physical arrangement, and quantity of
  available oxygen.
• During this period heat generation increases,
  producing light to moderate volumes of smoke.
• It is during this stage that early detection can
  control the fire before significant losses occur.
  

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Fire evolution 2

• As the fire reaches the end of the incipient
  period, there is usually enough heat generation
  to permit the onset of open, visible flames.
• Once flames have appeared, the fire changes from
  a relatively minor situation to a serious event
  with rapid flame and heat growth.
• Ceiling temperatures can exceed 1,000 C within
  the first minutes.
• Within 3-5 minutes, the room ceiling acts like a
  broiler, raising temperatures high enough to
  "flash", which simultaneously ignites all
  combustibles in the room.

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Conventional or "point wired"

• One or more circuits are routed through the
  protected space with one or more detection
  devices.
• Upon fire occurrence, one or more detectors will
  operate. This action closes the circuit, which
  the fire control panel recognizes as an emergency
  condition. The panel will then activate one or
  more signaling circuits to sound building alarms
  and summon emergency help.
• These systems monitor the condition of each
  circuit by sending a small current through the
  wires.

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Convn. systems maintenance

• Conventional systems may also be inherently labor
  intensive and expensive to maintain.
• Each detection device may require some form of
  operational test to verify it is in working
  condition.
• Smoke detectors must be periodically removed,
  cleaned, and recalibrated to prevent improper
  operation.
• If a fault occurs, the "trouble" indication only
  states that the circuit has failed, but does not
  specifically state where the problem is
  occurring.

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Addressable systems

• SW monitor and control the capabilities of each
  alarm initiating and signaling device.
• Each initiating device (automatic detector,
  manual station, sprinkler waterflow switch, etc.)
  is given a specific identification or "address".
• The system monitors the condition of each
  circuit, identifying any faults which may occur.
• It can specifically identify where a fault has
  developed.
• This permits faster diagnosis of the trouble, and
  allows a quicker repair and return to normal.

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Maintenance

• As a detector becomes dirty, the microprocessor
  recognizes a decreased capability, and provides a
  maintenance alert.
• This feature, known as Listed Integral
  Sensitivity Testing, allows facilities personnel
  to service only those detectors that need
  attention
• Modifying these systems, such as to add or delete
  a detector, involves connecting or removing the
  respective device from the addressable circuit,
  and changing the appropriate memory section

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Thermal detectors

• Fixed temperature devices that operate when the
  room reaches a predetermined temperature (usually
  in the 135-165F/57-74C).
• Rate-of-rise detector, which identifies an
  abnormally fast temperature climb over a short
  time period.
• Both of these units are "spot type" detectors,
  which means that they are periodically spaced
  along a ceiling or high on a wall.

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Thermal detectors are

• Highly reliable and have good resistance to
  operation from nonhostile sources.
• On the down side, they do not function until room
  temperatures have reached a substantial
  temperature.
• Subsequently, thermal detectors are usually not
  permitted in life safety applications.
• They are also not recommended in locations where
  there is a desire to identify a fire before
  substantial flames occur.

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Smoke detectors

• Ioniske
• Infrarøde sensorer

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Autronica Conventional, fire detection system
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(No Transcript)
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Detectors
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MultiSensor

• The MultiSensor will give a fast response to both
  flame fires and smouldering (slow burning) fires.
• The heat sensor may be set to different alarm
  limits, - grade 1, 2 or 3 according to the EN-54
  norms.
• All detection devices have an integrated short
  circuit isolator.

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Dynamic Filter Process, DYFI
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Detector applications

• The MultiSensor
• fast response to a flame fire and invisible fumes
  generated by over-heated technical installations.
• All technical rooms in accommodation, engine room
  spaces, el-lockers, A.C.-rooms and generally in
  spaces where ih a hot flame firels can be
  expected.
• Optical smoke detectors
• The optical smoke detector is ideal for detecting
  a slow burning fire (smouldering fire) generating
  visible smoke particles.
• Cabins, public areas, stairs, corridors, small
  lockers and stores within the accommodation
  areas.
• Heat detectors
• Galley and sauna area.

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fire safety management system
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Loop Input/Output unit

• The units are used for fire related functions as
• Doors
• Fans / Ventilation
• Dampers
• LLL (Low Locationing Light)
• Fire pumps
• Extinguishing systems

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AutroMaster 5000
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By means of the AutroMaster 5000 system it is
possible to

• indicate fire spread and smoke concentration,
• indicate and control smoke and heat detectors,
• indicate the sprinkler system,
• indicate and control low location lights,
• indicate and control individual fire doors,
• indicate and control fire dampers,
• indicate fire extinguishers,
• indicate fire fighting equipment
• indicate high voltage lines.