Transcript BUILDINGS AND STRUCTURES

Buildings and Structures 2
Fixed Installations
Aim
To provide students with information to
allow them to recognise the types of
fixed fire protection systems found in
buildings and the firefighting and the
considerations needed when dealing
with incidents involving such systems.
Learning Outcomes
At the end of the session students will be
able to state:
• The types of systems found in buildings
• The basic principles of operation
• The practical firefighting considerations.
Sprinkler systems
• Designed in accordance with
British standard 5306 part 2
• Governed by Loss Prevention
Council (LPC) rules for automatic
sprinkler systems.
Sprinkler systems
Main components
• A water supply
• A range of pipe work
• Sprinkler heads
• An alarm.
Three types of sprinkler systems
• WET pipe system
• DRY pipe system
• ALTERNATE wet and dry system.
Reasons for different types
• WET systems are installed in areas
where there is no danger of freezing
• DRY systems are installed where the
temperature is artificially maintained at
below 0° centigrade or above 70 °
centigrade.
Wet system.
Alternate system.
Sprinklers
Water supplies
• Town mains
• Gravity tank
• Elevated private reservoir
• Suction tanks and booster pumps.
Sprinkler system controls
Sprinkler systems are fitted with a variety
of controls and gauges, those of
importance to firefighters are;
• The main stop valve (MSV)
• Alarm devices.
Main stop valve (MSV)
• Isolates water supply, once fire is
extinguished, to mitigate water damage
• Must be right handed thread
(clockwise closing).
Main stop valve (MSV)
• Handwheel marked to indicate direction
of operation
• Indication of whether valve is open or
shut
• MSV must be secured open by means
of a strap and lock.
Main stop valve (MSV).
Controls
• A plan showing location of MSV must
be placed in the building where it can
be easily seen by firefighters
• Additionally an indicator plate must be
fixed to an external wall as close to
the MSV as possible.
Controls.
Sprinkler alarms
• Every installation must be fitted with an
approved water motor alarm
• Alarm actuated by water flowing into the
system
• Water turbine (Pelton wheel) actuates a
hammer that strikes against a gong.
Typical alarm.
Multiple systems
Where a building has more than one
installation fitted, each gong shall be
numbered in bold figures that
correspond to the number painted on
the controlling valves of each
installation.
Alarm sounding
There are four main reasons why sprinkler
alarm gongs operate;
• Opening of sprinkler head
• Opening of a drain or test valve
• Leakage from the system due to
damage
• A rise in the incoming water supply
pressure.
Firefighting considerations(1)
• On arrival, one member of the crew to be
sent to the MSV
• The MSV can be opened if found closed
• The valve MUST NOT be closed, except
on the express instructions of the
Incident Commander.
Firefighting considerations(2)
• If the system is fitted with a fire brigade
inlet the principal supply of water can be
augmented
• Additional water should not be extracted
from the same main that feeds the
installation.
Firefighting considerations(3)
• Sprinklers should not normally be turned
off in order to fight the fire with jets or
spray branches
• Although sprinklers may appear to have
extinguished the fire,careful examination
of the scene is still essential to confirm
that the fire is out.
Drencher systems
• Sprinkler systems are installed to
protect the interior of a building
• DRENCHER systems are designed
to protect the external openings of a
building from exposure to fire from
adjacent buildings.
Three types of drencher systems
• ROOF drenchers
• WALL drenchers
• WINDOW drenchers.
Foam inlets
• Compartments containing oil or other
flammable liquids can be protected by fixed
piping through which foam can be pumped
• The piping terminates in a fire service inlet
usually protected by a glass panel marked
FOAM INLET.
Typical foam inlet.
Rising Mains
Vertical pipe installed in a building with an
inlet at ground level and outlets at various
levels for fire service use. There are 2 types;
• Wet
• Dry.
Rising mains.
Landing valve.
Carbon dioxide (CO2) installations
Confined to the protection of hazards located
in buildings or those around which a protective
screen can be erected, for example;
•
•
•
Electrical apparatus
Paint stores
Libraries and archives.
CO2 installation.
Safety features
• Systems must be fitted with a means to
immobilise the equipment
• Automatic systems must not operate
whilst compartments are occupied
• Provision is made for for locking off the
auto facility, leaving a manual override
control.
Warning sign
Areas protected by carbon dioxide systems
should be identified by a warning sign sited
near the entrance to such areas.
Confirmation
Assessments will be based on this lesson and
the corresponding study note
Learning Outcomes
• The types of systems found in buildings
• The basic principles of operation
• The practical firefighting considerations.
THE END