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Chapter 05

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Chapter 05

  1. 1. Automatic Fire Sprinkler Systems Chapter 5
  2. 2. Learning Objectives <ul><li>Describe an automatic fire sprinkler system </li></ul><ul><li>Discuss the myths and realities associated with automatic fire sprinkler system operation </li></ul><ul><li>State the factors that determine requirements to install automatic fire sprinkler systems </li></ul><ul><li>Discuss the design concepts behind automatic fire sprinkler systems </li></ul>
  3. 3. Learning Objectives (continued) <ul><li>List and describe different occupancy and commodity classification </li></ul><ul><li>Describe different types of automatic fire sprinkler systems and the best applications for those systems </li></ul><ul><li>Discuss the inspection and test requirements for acceptance of water-based fire protection systems </li></ul>
  4. 4. Introduction <ul><li>Automatic fire sprinkler system : network of piping with sprinkler heads at specific intervals </li></ul><ul><ul><li>Upon activation, applies water over the fire area </li></ul></ul><ul><li>Common myths: </li></ul><ul><ul><li>All sprinkler heads operate simultaneously </li></ul></ul><ul><ul><li>Sprinkler heads activate for no reason </li></ul></ul><ul><ul><li>Water discharged will cause a flood or drown a person </li></ul></ul><ul><ul><li>Costs more to repair water damage than fire damage </li></ul></ul><ul><ul><li>Smoke detector activation will cause sprinkler to operate </li></ul></ul>
  5. 5. Introduction (continued) <ul><li>Facts about sprinkler heads: </li></ul><ul><ul><li>Operate independently, only in fire area </li></ul></ul><ul><ul><li>Undergo numerous tests by third-party organizations </li></ul></ul><ul><ul><ul><li>Rarely accidentally activate </li></ul></ul></ul><ul><ul><li>Exposure to fire and smoke damage limited </li></ul></ul><ul><ul><ul><li>Fire hose could cause substantially more damage </li></ul></ul></ul><ul><ul><li>Majority of smoke detectors operate independently of sprinkler systems </li></ul></ul>
  6. 6. Effectiveness in Property Protection <ul><li>Basis for sprinkler system design is to keep a fire at a relatively small size, under control </li></ul><ul><li>Prevents extensive damage that would have closed the facility, injured occupants </li></ul><ul><li>Frequently, businesses never recover from a fire when there are injuries or loss of life </li></ul>
  7. 7. Effectiveness in Life Safety <ul><li>Primary purpose is to provide property protection </li></ul><ul><ul><li>Not necessarily life safety </li></ul></ul><ul><li>Sprinklers provide some level of life safety </li></ul><ul><ul><li>Systems may interact with other building safety systems </li></ul></ul><ul><li>Residential systems provide higher level of life safety </li></ul><ul><li>Not more than two people have died in a fire where complete sprinkler system installed </li></ul>
  8. 8. Required Installations <ul><li>Most early requirements came from property insurance companies </li></ul><ul><li>Requirements changed with development of model codes </li></ul><ul><ul><li>Changes were gradual </li></ul></ul><ul><ul><li>Code changes only affected new building construction </li></ul></ul><ul><li>Incentives provided for installation of automatic fire sprinkler systems </li></ul><ul><li>Model codes today establish requirements based on use and occupancy conditions </li></ul>
  9. 9. Design and Installation Standards <ul><li>Published standards available from model code and insurance organizations </li></ul><ul><li>Three primary standards: </li></ul><ul><ul><li>NFPA 13: Installation of Sprinkler Systems </li></ul></ul><ul><ul><li>NFPA 13D: Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes </li></ul></ul><ul><ul><li>NFPA 13R: Installation of Sprinkler Systems in Residential Occupancies Up To and Including Four Stories in Height </li></ul></ul>
  10. 10. NFPA 13, Standard for the Installation of Sprinkler Systems <ul><li>First published in 1896 </li></ul><ul><li>Performance objective: maintain control of a fire </li></ul><ul><li>Contain the fire to general area of origin by applying water </li></ul><ul><li>Sprinkler heads cover all spaces in the building </li></ul><ul><ul><li>Includes concealed combustible spaces, attics, above and below ceilings </li></ul></ul><ul><li>In many cases, sprinkler can suppress the fire </li></ul>
  11. 11. NFPA 13D, Standard for the Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes <ul><li>Published in 1975 </li></ul><ul><li>Addresses residential fire problem </li></ul><ul><ul><li>Places sprinklers in home where fire likely to start </li></ul></ul><ul><ul><li>Excludes small bathrooms, closets, unheated areas </li></ul></ul><ul><li>Standard relies on research and testing data </li></ul>
  12. 12. NFPA 13R, Standard for the Installation of Sprinkler Systems in Residential Occupancies Up to and Including Four Stories in Height <ul><li>Concerns hotels, motels, apartments, condos </li></ul><ul><li>Loosely follows NFPA 13 requirements </li></ul><ul><li>At least one FDC in the building </li></ul><ul><li>Places sprinkler heads where fire most likely to start </li></ul>
  13. 13. Other Fire Sprinkler Standards <ul><li>Other standards deal with level of hazard exceeding NFPA 13 </li></ul><ul><li>Standards state the applicability </li></ul><ul><ul><li>Establish design criteria based on conditions </li></ul></ul><ul><ul><li>Specify sprinkler head characteristics and appropriate types </li></ul></ul><ul><li>Do not specify installation methods or dictate how to lay out a system </li></ul><ul><li>Ultimately the design professional determines the type of system best suited to the hazard </li></ul>
  14. 14. Design Concepts for Automatic Fire Sprinkler Systems <ul><li>Design starts with classifying the occupancy, commodities, storage arrangement </li></ul><ul><ul><li>Evaluate the combustibility </li></ul></ul><ul><li>System must deliver enough water to absorb energy from the fire </li></ul><ul><li>Design professional decides whether to use a pipe schedule or hydraulic design </li></ul>
  15. 15. Design Concepts for Automatic Fire Sprinkler Systems (continued) <ul><li>Density/area curves: graphic representation of a minimum amount of water over a specific area </li></ul><ul><li>Amount of water is minimum design density </li></ul><ul><ul><li>Area of coverage is the remote area </li></ul></ul><ul><li>Contractor records system information on hydraulic design information sign </li></ul>
  16. 16. Fire Sprinkler System Components <ul><li>Components require listing or approval from third-party testing and certification laboratory </li></ul><ul><ul><li>Underwriters Laboratories, FM Global </li></ul></ul><ul><li>Many supporting components are common to all the different types of fire sprinkler systems </li></ul><ul><li>Each type of automatic sprinkler system uses specific type of valve </li></ul><ul><li>Some design and installation objectives require special types of sprinkler heads </li></ul>
  17. 17. Pipe and Fittings <ul><li>Join together to provide a conduit for water </li></ul><ul><li>Must handle maximum permitted system working pressure of 175 psi </li></ul><ul><li>ASTM standard establishes internal and external pipe dimensions and wall thicknesses </li></ul><ul><li>Thinner pipe has larger internal diameter </li></ul><ul><ul><li>Offers hydraulic design advantages because there is less friction loss </li></ul></ul><ul><li>CPVC pipe dominant type of piping used for residential installations </li></ul>
  18. 18. Gauges <ul><li>Pressure gauges important </li></ul><ul><li>Some systems have water gauges </li></ul><ul><ul><li>Other systems have water and air gauges </li></ul></ul><ul><li>Help to determine whether there is a problem with the system </li></ul><ul><li>Should not be subject to freezing temperatures </li></ul><ul><li>Each should have a control valve capable of draining </li></ul>
  19. 19. Valves <ul><li>Water control valves permit water to flow into and through the system when open </li></ul><ul><ul><li>Prevent water flow, isolate parts of the system when closed </li></ul></ul><ul><li>Valves placed in locations that are clearly accessible </li></ul><ul><li>Water control valves must be indicating-type </li></ul><ul><ul><li>Must handle 175 psi </li></ul></ul><ul><li>Check valves permit water or air to flow in one direction </li></ul>
  20. 20. Support and Stabilization of Pipe <ul><li>Majority of piping runs horizontally across ceiling </li></ul><ul><ul><li>Fasteners stabilize the pipe </li></ul></ul><ul><ul><li>Riser clamps hold vertical pipes in position </li></ul></ul><ul><li>All supporting materials must be made of ferrous materials for heat resistance </li></ul><ul><li>Spacing and location of hanger components depend on the size and type of piping </li></ul><ul><li>Hanger assembly consists of fastener, threaded rod, ring that holds the pipe </li></ul><ul><ul><li>Bracing, guides, restraints provide stability </li></ul></ul>
  21. 21. Automatic Sprinkler Heads <ul><li>Spray device that distributes water over a limited area at a designated flow rate </li></ul><ul><li>Reduces heat from a fire </li></ul><ul><ul><li>Limits and controls fire’s growth </li></ul></ul><ul><li>Heat-activated </li></ul><ul><ul><li>Heat-sensitive element head releases so that the parts holding back the water fall away </li></ul></ul><ul><li>Each head operates independently </li></ul>
  22. 22. Automatic Sprinkler Heads (continued) <ul><li>Frame holds other pieces in place </li></ul><ul><li>Heat-sensitive element attach to the frame, hold orifice cap in place </li></ul><ul><li>Orifice is the smooth opening in the head through which water flows from the pipe </li></ul><ul><li>Orifice cap covers the orifice </li></ul><ul><li>Deflector creates the spray pattern of the water </li></ul>
  23. 23. Automatic Sprinkler Heads (continued) <ul><li>Types of sprinkler heads </li></ul><ul><ul><li>Old Style, Standard Spray, Specialty Heads </li></ul></ul><ul><ul><li>Pendent, Upright, and Sidewall Heads </li></ul></ul><ul><ul><li>Special Application Sprinkler Head Identification </li></ul></ul><ul><ul><li>Heads for Particular Conditions and Applications </li></ul></ul><ul><ul><li>Heads for Aesthetic Purposes </li></ul></ul><ul><li>K-factor classifies the head by factor number </li></ul><ul><li>Modern heads resemble heads of 100 years ago </li></ul>
  24. 24. Types of Systems <ul><li>Four basic types of automatic fire sprinkler systems </li></ul><ul><li>Each has characteristics appropriate for particular situations and applications </li></ul><ul><li>Most commonly installed types of systems </li></ul><ul><li>Basis for other types of water-based fire protection systems </li></ul>
  25. 25. Wet Pipe Systems <ul><li>Least expensive, most frequently installed </li></ul><ul><ul><li>Easiest to maintain, modify, and most reliable </li></ul></ul><ul><li>Limited area sprinkler systems provide protection without installing full building system </li></ul><ul><li>Require dedicated water supply and usually have an alarm check valve </li></ul><ul><li>Clapper inside the valve acts as a check valve </li></ul><ul><li>Common in almost every type of building </li></ul>
  26. 26. Figure 5-29 Wet pipe sprinkler system schematic
  27. 27. Dry Pipe Systems <ul><li>Best system to protect building where temperature falls below 40 degrees </li></ul><ul><ul><li>Unheated warehouses, attics, loading docks, etc. </li></ul></ul><ul><li>Pressurized air maintained in the system piping until system activates </li></ul><ul><li>Dry pipe valves prevents water from entering the system until needed </li></ul><ul><ul><li>Operates on water-to-air differential </li></ul></ul><ul><li>Size and layout of system affects time to deliver water </li></ul>
  28. 28. Figure 5-31 Dry pipe sprinkler system schematic
  29. 29. Pre-action Systems <ul><li>Similar to dry pipe systems, using closed sprinkler heads </li></ul><ul><li>Normally no water in system piping </li></ul><ul><li>Fire detectors release the pre-action valve </li></ul><ul><li>Require two separate events before water discharges </li></ul><ul><ul><li>Fire detector activates and releases pre-action valve </li></ul></ul><ul><ul><li>Sprinkler head activates to flow water </li></ul></ul>
  30. 30. Figure 5-35 Pre-action sprinkler system schematic
  31. 31. Deluge Systems <ul><li>Operate similar to pre-action systems </li></ul><ul><li>Open to the atmosphere because sprinkler heads open to the atmosphere </li></ul><ul><li>Open sprinkler heads do not have a heat-sensing element </li></ul><ul><li>Discharge immediate and simultaneous from all sprinkler heads </li></ul><ul><li>Deluge valve receives signal from detection system </li></ul>
  32. 32. Figure 5-37 Deluge sprinkler system schematic
  33. 33. Residential Sprinkler Systems <ul><li>Benefits derive from change in emphasis from property protection to life protection </li></ul><ul><li>Design concepts: </li></ul><ul><ul><li>Prevent flashover </li></ul></ul><ul><ul><li>Improve occupants chance for rescue or escape </li></ul></ul><ul><li>Vast majority are wet pipe systems </li></ul><ul><li>Many share water supplied by domestic water line </li></ul><ul><li>Residential sprinkler head satisfies different testing criteria </li></ul>
  34. 34. Inspection, Testing, and Maintenance Requirements <ul><li>Approval process for automatic sprinklers similar to fire lines and standpipes </li></ul><ul><li>Approving authority determines if system installed according to plans </li></ul><ul><li>Requirements are in various standards used to design the systems </li></ul><ul><li>Most periodic inspections, tests and maintenance follow inspection and test protocols </li></ul>
  35. 35. Acceptance Inspections and Tests <ul><li>Acceptance inspections during construction similar from system to system </li></ul><ul><li>Flushing : incoming fire line requires flushing before connecting water supply to sprinkler </li></ul><ul><li>Hydrostatic air tests : subjects system to predetermined pressure for minimum duration </li></ul><ul><li>Hydrostatic tests for residential systems : verify no system leaks with source water pressure </li></ul>
  36. 36. Acceptance Inspections and Tests (continued) <ul><li>Visual inspection : confirm the design and installation meet standards </li></ul><ul><li>Operation of Components : verify that the system will operate when needed </li></ul><ul><li>Main Drain Test : establishes that the incoming water supply is adequate, with no impairments </li></ul>
  37. 37. Periodic Inspection, Testing, and Maintenance <ul><li>Provide a level of certainty that the system will operate when called upon </li></ul><ul><li>Same tests used to accept a system can be used to verify proper operation </li></ul><ul><ul><li>Conducted at regular intervals </li></ul></ul><ul><li>Impairments result from a lack of maintenance, component failure, etc. </li></ul><ul><li>Typical impairments: closed control valves, damaged sprinkler heads, broken piping, etc. </li></ul>
  38. 38. Summary <ul><li>Sprinkler systems designed to keep a fire small and under control </li></ul><ul><li>Not all automatic sprinkler systems are alike </li></ul><ul><li>For well over 100 years, sprinkler systems have protected property and life </li></ul><ul><li>Automatic fire sprinkler systems offer building owners and homeowners a reliable, effective, economical, and proven protection system </li></ul>

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