1. Combined Fire-fighting/Irrigation
Pumping Stations Design and Control
Philosophy
Clare Edwards
Thursday 6th September 2007

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. Potable/Firefighting - GM University

4. Irrigation/Firefighting - UAQ Marina

5. Information We’re Given
• Users
• Flow
• Pressure at point of discharge
• Network – distances
• Location – sometimes not always known e.g. Lusail

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. 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. Calculations
• Pipe sizing
– Q = vA
• Headloss Calculations
– Colebrook-White formula
• Motor Sizing Calculation
– P = ρ gHQ / η

9. Example
• Q = 620 l/s
• HT = 80m
• Combined Fire/Irrigation
• Pressure at hydrant
• Maintain 2 hours storage for fire
event

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. Pipe Velocities
• 350 dia => 2.15m/s
• 400 dia => 1.65m/s
• 500 dia => 1.05m/s
• 600 dia => 0.73m/s

12. Headloss Calculation
• Use Colebrook-White to calculate headloss
in pipe
– Length & diameter of pipe
– Flow => velocity
– Fittings
• HL= kV²/2g
• HF =
• HT =

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. Pumps
• Electric Pump with diesel backup/diesel generator backup
• Irrigation Pump/s with jockey pump/s
• Centrifugal pumps (split casing type)
• Vertical multistage

15. Pump Selection

16. General Arrangement – Pipe Layout

17. Process & Instrumentation Diagram P&ID

18. P&ID (cont)

19. Single Line Diagram

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. 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. Standards – FM/UL Approved
• FM - Factory Mutual
• UL – Underwriters Laboratory

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. 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. Actions in event of fire
Fire hydrant opened
Fire pumps start Irrigation & district cooling offtakes close
Detect that fire hydrant has been opened

26. Variations
• GM University

27. GM University – Potable/Firefighting

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. 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. Pump Room Overview

31. Electric Fire Pump

32. Diesel Fire Pump

33. Pressure Relief Valve

34. Flowmeter

35. Autostrainers

36. IMPZ, Dubai

37. Valve Arrangement

38. Surge Tank

39. Monorail Crane

40. Tied Pipework