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chapter 9 water-based fire protection systems equipment

Water as an Extinguishing Agent. The great majority of fires are extinguished using water.Water is usually available at or near the fire scene and has special physical properties well suited for fire fighting.. Extinguishing Properties of Water. Cooling

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chapter 9 water-based fire protection systems equipment

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    1. Chapter 9 Water-Based Fire Protection Systems & Equipment

    3. Extinguishing Properties of Water Cooling – depends on how quickly water is applied, how much is applied and what form. Water absorbs the most heat when it is converted to steam and that is more easily performed from droplets. Smothering – foaming agent is usually added to the water. Emulsification – Cools surface of flammable liquids and prevents release of flammable vapors. Dilution – for fires in water-soluble flammable materials.

    4. Electrical Conductivity of Water Water in its natural state contains impurities that make it conductive. If water is applied to fires involving electricity, continuous circuit may be formed and shock applier. Water-based foam agents are very conductive.

    5. Using Water on Special Hazards Chemicals Combustible Metals Radioactive Materials Gases Combustible & Flammable Liquids Cooling agent Mechanical tool Displacing medium

    6. Water Main Valves Control water flow through distribution piping Should be operated at least once a year Include two types Indicating Non-indicating

    7. Types of Valves

    8. Friction Loss That part of the total pressure lost as water moves through a piping system or hose.

    9. Increased Friction Loss

    10. Types of Fire Hydrants

    11. Dry-Barrel Fire Hydrants Used in climates where freezing weather is expected. Compression, gate, or knuckle-joint opens either with pressure or against pressure. When hydrant is closed, the barrel is empty from the hydrant down to the main valve. Any water remaining in hydrant should be drained.

    12. Wet-Barrel Fire Hydrants Are used in areas that do not have freezing weather. Are always filled with water to the valves near the discharges.

    13. Hydrant Flow & Location Flow — Varies; coloring hydrants helps indicate range of water flow Location Should not be spaced more than 300 feet apart in high-value districts Are usually placed near each street intersection, with intermediate hydrants where distances between intersections exceed 350 to 400 feet

    14. Hydrant Inspection & Maintenance Obstructions preventing pumper-to-hydrant connections Outlets facing proper direction for pumper-to-hydrant connections Sufficient clearance between the outlets and ground for hose connections Damage

    15. Sprinkler System Design & Operation Series of sprinklers arranged to automatically distribute enough water to extinguish or check fire. Water is supplied to sprinklers through a piping system. System’s sprinkler heads discharge water after a cap or plug is released by a heat-responsive element. NFPA 13 – Standard for the Installation of Sprinkler Systems, but other NFPA standards also have a direct bearing on certain phases of sprinkler protection.

    16. Sprinkler System Advantages Most reliable Most effective (control 96% of fires in sprinkler-protected buildings) Less business interruption Less water damage Enhance life safety Reduce insurance costs

    17. Parts of a Sprinkler Head

    18. Releasing Mechanisms

    19. How the Bulb Works Heat from fire heats liquid in bulb & breaks. Releases cap. Water is released onto diffuser. Water puts out fire.

    20. Sprinkler Head Temp Ratings Sprinkler heads are designed with temperature ratings ranging from 135oF to as high as 500oF. Ratings of 165oF are common for use in buildings maintained at normal, constant temperatures.

    21. Sprinkler Bulb Colors

    22. Sprinkler Head Designs

    23. Control Valve Location

    24. Sprinkler System Main Control Valve Purpose — Cutting off the water supply to the system so that sprinklers can be replaced, maintenance performed, or operations interrupted Location — Immediately under the sprinkler alarm valve, the dry-pipe or deluge valve, or outside the building near the system connections Position after maintenance — Open Type — Manual indicating valve

    25. Types of Sprinkler Systems Wet Pipe Dry Pipe Preaction Deluge Combined Dry Pipe & Preaction Special

    26. Wet Pipe Sprinkler System Uses a piping system containing water under pressure at all times. When a fire occurs, individual sprinklers are activated by heat, and water flows through those sprinklers immediately. Generally used wherever there is no danger of the water in the pipes freezing and no special conditions requiring one of the other systems.

    27. Wet Pipe Sprinkler System

    28. Dry Pipe Sprinkler System Sprinklers attached to piping which contains air or nitrogen under pressure. When a sprinkler is opened by heat, the pressure is reduced to the point where water pressure on the supply side can force open the valve. Then water flows into the system and out any opened sprinklers.

    29. Dry Pipe Sprinkler System

    30. Preaction System Contain air in the piping that may or may not be under pressure. When a fire occur, a supplementary fire detecting device in the area is activated. This opens a water control valve which permits water to flow into the piping system before a sprinkler is activated. When sprinklers are opened by heat of the fire, water flows through the sprinklers immediately – same as a wet pipe system.

    31. Preaction System

    32. Deluge System System has all sprinklers open at all times. When heat from a fire activates the fire detecting device, the deluge valve opens and water flows to, and is discharged from, all sprinklers on the piping system, thus deluging the protected system.

    33. Deluge System

    34. Combined Dry Pipe & Preaction System System includes essential features of both types of systems. Piping system contains air under pressure. Supplementary heat detecting device opens the water control valve and an air exhauster at the end of the unheated feed main. The system then fills with water and operates as a wet pipe system. If supplementary heat detecting system should fail, the system will operate as a conventional dry pipe system.

    35. Special Types These systems depart from NFPA 13 requirements in areas such as special water supplies and reduced pipe sizes.

    36. Situations In Which Sprinklers Are Effective Preventing fire spread upwards in multiple- story buildings. Protecting the lives of occupants in other parts of the building.

    37. Situations In Which Sprinklers May Not Be Effective Fires too small to activate sprinkler system. Smoke reaches occupants before sprinkler system activates. Sleeping, intoxicated, or handicapped persons occupy fire building.

    39. Sprinkler-Related NFPA Standards NFPA 13 – Installation of Sprinkler Systems NFPA 13D – Installation of Sprinkler Systems in Family Dwellings NFPA 13R – Installation of Sprinkler Systems in Residential Occupancies up to 4 stories NFPA 14 – Installation of Standpipe & Hose Systems NFPA 15 – Water Spray Fixed Systems NFPA 16 – Installation of Foam-Water Systems NFPA 25 – Inspection, Testing & Maintenance of Water-Based Fire Protection Systems

    40. Summary Properties of Water Water Supply Systems Types of Valves & Hydrants Sprinkler Systems Advantages Parts Heads Types Why they fail Standpipe & Hose Systems

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