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 (CO 2 ) 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.

CO 2 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.

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