Fire irrig ps

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  • Different pressure requirements
  • Don’t want velocity too low as…
    Pumps become inefficient, cost of associated fittings increases.
    Usual to increase pipe dia on suction side to reduce suction head required by pump
  • NPFA20 - main code that governs fire pump installations
  • When hydrant opened need to increase pressure
    Fire pumps
    Close irr & DC offtakes to maintain water in reservoirs (reservoirs can be smaller)
    So irr pipes & fittings do not experience fire pressure
    So fire pumps can be smaller
    CLICK
    Need to detect when a fire hydrant has been opened to trigger this.
  • PGD 476 International Media Production Zone
  • Fire irrig ps

    1. 1. Combined Fire-fighting/Irrigation Pumping Stations Design and Control Philosophy Clare Edwards Thursday 6th September 2007
    2. 2. Introduction • Fire/Irrigation Pumping Stations • Fire/Potable Water Pumping Stations – What we’re given – What we produce – Pumping station – Standards – Control Philosophy – Problems encountered – Summary
    3. 3. Potable/Firefighting - GM University
    4. 4. Irrigation/Firefighting - UAQ Marina
    5. 5. Information We’re Given • Users • Flow • Pressure at point of discharge • Network – distances • Location – sometimes not always known e.g. Lusail
    6. 6. Water Users & Pressure Required Potable Water Supply • Potable only • ~ 4 bar (58 psi) Fire Fighting • Potable or treated effluent • ~ 7 bar (102 psi) Irrigation • Treated effluent • ~ 4 bar (58 psi) District Cooling • Treated effluent • ~ 4 bar (58 psi)
    7. 7. What we Produce • M&E specifications – specifying equipment, pumps, mechanical equipment – a standard document that is changed edited for the purposes of the project – includes pump curves, datasheets, panel dimensions, etc • Calculations – Size of pipes, headloss calculations, motor sizing, thrust on pipe calculations, power load, any further calculations required • Drawings – P&ID, SLD, GA showing pipe layout, sections, pipe schedules, roof/access layout • Control Philosophy – how we propose to operate & control the system
    8. 8. Calculations • Pipe sizing – Q = vA • Headloss Calculations – Colebrook-White formula • Motor Sizing Calculation – P = ρ gHQ / η
    9. 9. Example • Q = 620 l/s • HT = 80m • Combined Fire/Irrigation • Pressure at hydrant • Maintain 2 hours storage for fire event
    10. 10. Pipe Size & Headloss Calculation • E.g. Irrigation pump, velocity in pipe<2m/s • No of pumps required – D/A/A/S => Duty, Q = 207l/s (620/3) • Try Dia = 400mm • => A = 0.4²π/4 = 0.12m² • V = Q/A => 0.207/0.12 = 1.65m/s
    11. 11. Pipe Velocities • 350 dia => 2.15m/s • 400 dia => 1.65m/s • 500 dia => 1.05m/s • 600 dia => 0.73m/s
    12. 12. Headloss Calculation • Use Colebrook-White to calculate headloss in pipe – Length & diameter of pipe – Flow => velocity – Fittings • HL= kV²/2g • HF = • HT =
    13. 13. Motor Sizing Calculation • P = ρ gHQ /η • P = (1000kg/m² x 9.81m/s² x 80m x0.207m³/s)/ 0.8 • P = 203kW + 10% design headroom • kW => type of starter • DEWA recommendations – 0-11kW DOL – 15-22kW Star-Delta – 30+ kW Soft Start
    14. 14. Pumps • Electric Pump with diesel backup/diesel generator backup • Irrigation Pump/s with jockey pump/s • Centrifugal pumps (split casing type) • Vertical multistage
    15. 15. Pump Selection
    16. 16. General Arrangement – Pipe Layout
    17. 17. Process & Instrumentation Diagram P&ID
    18. 18. P&ID (cont)
    19. 19. Single Line Diagram
    20. 20. Main Components • - storage tank/reservoir – level sensors • - pump room • - FEP, FDP, Irrigation pumps, (Potable pumps), jockey pumps • - valves – flow control and isolation • - flow meter – to test pump flow rates • - surge vessel – maintain system pressure • - (strainers) • - lifting equipment – overhead bi-directional crane • - generator, MCC, transformer, mess rooms/building • - fuel tank • - standby generator • - AC and ventilation
    21. 21. Standards – NFPA20 • NFPA 20 – National Fire Protection Association's (NFPA) – American standard adopted in the UAE – NFPA 20 Standard for the Installation of Stationary Fire Pumps for Fire Protection • Key points: – Pumps limited to capacity < 1892 l/min – PRV
    22. 22. Standards – FM/UL Approved • FM - Factory Mutual • UL – Underwriters Laboratory
    23. 23. Control Philosophy • Instruction on how pumping station will operate – state set points; – pressure pumps are to maintain the system at; – how the pumps will operate, e.g. D/A/A/S – what controls are needed • Control Philosophy and P&ID is then given to the electrical engineer to complete the SLD, panel layout, and work out electrical loads and power required, size standby generators, etc • Control Philosophy to be read in conjunction with P&ID
    24. 24. Control Philosophy Assumptions • Irrigation pumps to operate on demand, • Jockey pumps to maintain system pressure • Irrigation networks under central control • Each branch of network can be isolated (normal condition) or opened when irrigation is required. • Valves centrally controlled • Irrigation system controlled by a 24 hour timer • A PRV to protect pumps and pipework against over pressure. • Back up diesel generator – for mains power failure • Sufficient fire-fighting water must be available at all times Hard-wired level sensor in tank to inhibit irrigation pumps • Flow control valve provided on inlet to storage tank/reservoir.
    25. 25. Actions in event of fire Fire hydrant opened Fire pumps start Irrigation & district cooling offtakes close Detect that fire hydrant has been opened
    26. 26. Variations • GM University
    27. 27. GM University – Potable/Firefighting
    28. 28. Problems • Strainers on suction pipework • D/S strainers requested when the tank and pumping station • Determining what Civil Defence wants? • Surge vessels • Pipe thrust block design • Ensuring pipework is tied down
    29. 29. Summary • Good examples of design from various projects • However…. • …we’re constantly working and improving on the design • The most important thing is determining what the civil defence requirements are and confirming the design criteria as early as possible
    30. 30. Pump Room Overview
    31. 31. Electric Fire Pump
    32. 32. Diesel Fire Pump
    33. 33. Pressure Relief Valve
    34. 34. Flowmeter
    35. 35. Autostrainers
    36. 36. IMPZ, Dubai
    37. 37. Valve Arrangement
    38. 38. Surge Tank
    39. 39. Monorail Crane
    40. 40. Tied Pipework

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