Course Outline Water Supply Analysis Need for Fire Pumps Types of Pumps & Drivers Pump Placement & Sizing Piping & Appurtenances Inspection, Testing & Maintenance
Jan 29, 2016
Course Outline
Water Supply Analysis Need for Fire Pumps Types of Pumps & Drivers Pump Placement & Sizing Piping & Appurtenances Inspection, Testing & Maintenance
Reference Standards
NFPA 20 - Fire Pumps
NFPA 22 - Water Storage Tanks NFPA 24 - Fire Service Mains NFPA 25 - Inspection, Testing and
Maintenance of Water Based Fire Protection Systems
Basic Hydraulics Flow
– Volume of water moving through a system (or past a point) in a given period of time
– measured in gpm or L/min Pressure
– The energy available to do work (move water)
– Measured in psi or bar
Basic Hydraulics
Head– Another way of expressing energy based on
the equivalent height of a fluid column– measured in feet or meters
Pressure/HeadRelationship for Water
P = .433H
P = Pressure in psi
H = Height of elevation of water in feet
Tank
WaterLevel
150 ft
Laminar Flow
Turbulent Flow
Laminar & Turbulent Flow
Water Supply Analysis
Perform flow tests Adjust for realistic worst case
– Time of day– Time of year
Take into account future growth
FLOW
Sprinkler System Underground
Pressure or Test Hydrant
Pressure Gauge
Flow Hydrant
WATER MAIN
EXAMPLE Static Pressure ..................... 80 psi Residual Pressure ................ 47 psi Pitot Reading ....................... 14 Hydrant Coefficient .............. .90 Butt Opening ........................ 2.5 inches Flow = ?
Flow Formula
Flow (in gpm) = Q = 29.83 x (D)2 x CH x (PT)1/2
Q = 29.83 x (2.5)2 x 0.9 x (14)1/2
Q = 29.83 x 6.25 x 0.9 x 3.74
Q = 627 gpm
100 200 300 400 500 600 700 800
PRESSURE
100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0
FLOW - GPM
FLOW TEST SUMMARY SHEET
PRESSURE
100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0
100 200 300 400 500 600 700 800
FLOW - GPM
FLOW TEST SUMMARY SHEET
FLOW TEST SUMMARY SHEET
PRESSURE
100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0
100 200 300 400 500 600 700 800
FLOW - GPM
Water Supply
Determining Pressure at Any Given Flow
Use graph of water supply data Use Formula: P = (PR - PS)(Q/QR)1.85 + PS
P = Pressure at any given flow
Q = Flow at which you want to know P
PR = Residual pressure measured in test
PS = Static pressure measured in test
QR = Residual flow measured in test
Adjustments Need to account for differences in elevation
between water supply and fire protection system (For this Example, assume none)
Need to evaluate water supply at reasonable worst case for daily and seasonal use
For this example– 24 hour gauge showed variation in static pressure from
72 to 84 psi– Seasonal knowledge of water supply says static
pressures vary from 65 to 85 psi
FLOW TEST SUMMARY SHEET
PRESSURE
100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0
100 200 300 400 500 600 700 800
FLOW - GPM
Water SupplyWater Supply - Adjusted for seasonal and daily use
Why Do We Need Pumps ?
When the water supply can provide sufficient flow, but does not have the pressure to meet the demand of the fire protection system, pump can be used
Pumps will not increase flow
FLOW TEST SUMMARY SHEET
PRESSURE
100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0
100 200 300 400 500 600 700 800
FLOW - GPM
Water Supply
FLOW TEST SUMMARY SHEET
PRESSURE
100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0
100 200 300 400 500 600 700 800
FLOW - GPM
Water Supply
Water Supply With Pump
Pump Pressures Discharge Pressure
– Gage pressure measured on the discharge flange of the pump
Suction Pressure– Gage pressure measured on the suction
flange of the pump– Energy of the water delivered to the pump– Function of water supply, not pump– Must be positive
Pump Pressures
Net Pressure– Pressure produced by the pump– Difference between Discharge Pressure and
Suction Pressure
PN = PD - PS
PD = PS + PN
Types of Pumps
Centrifugal Pumps - use centrifugal force to increase water’s energy (pressure)
Positive Displacement Pumps - push water with pistons or rotary gears to increase water’s energy (pressure)
Centrifugal Force An object dropped in the center of a
rotating disk will pick up energy from the rotation
The object will move towards the outside of the disk
If unrestrained, the object will be thrown off when the object reaches the edge (kinetic energy)
If restrained, the object will store the energy as potential energy (pressure)
Centrifugal Pump Components Impeller
– Vanes– Shrouds– Eye
Impeller Shaft Packing Casing
Impeller Shaft
Horizontal - attached to horizontal driver
Vertical - attached to vertical driver Vertical - attached to horizontal driver
through right angle gear drive
Packing
Seal between the inside of the pump and the outside of the pump where the shaft penetrates the casing
Must be kept moist Gland around packing designed to leak
Pump Design
Single Suction - Water only enters the eye on one side of the impeller
Double Suction - Water enters the impeller from both sides
Single Suction Double Suction
Multi-Stage Centrifugal Pumps
More than one impeller inside the casing
Parallel - water goes to all impellers simultaneously
Series - all of the water goes to one impeller first, then from that impeller into the next
Two-StagePump inParallel
Two-StagePump inSeries
Types of Centrifugal Pumps Horizontal Pump Vertical Pump End Suction Pump Horizontal Split Case Pump In-Line Pump Vertical (Line) Shaft Turbine Pump Can Pump
End Suction Pump
Horizontal Split Case Pump
Vertical In-Line Pump
Vertical Shaft Turbine Pump
Pump Drivers
Electric Motors Diesel Engines Steam Turbines Gasoline Engines - no longer allowed
Electric Motors
Power source must be reliable– Public Utility – Separate Service– Private Power Station
Noncombustible Construction
Secondary Power SourceRequired When:
1. Reliable power source cannot be obtained from a public utility or a private station.
2. The pump is protecting a high-rise building and the needs of the fire protection system cannot be supplied by FD pumper.
3. Another code or ordinance requires
Generators
Type 10, Level 1, Class X (8 hrs at 100% of rated capacity)
Handle All Loads– Load Shedding Allowed
Diesel Engines
Batteries Exhaust Ventilation Coolant Noise
Pump Drivers - Power Horsepower Brake Horsepower Gross Brake Horsepower Net Brake Horsepower Water Horsepower
WHPnet = Q x P
1714 x E
Pump Sizing and Placement
Pump Sizing
Rated Flow (25-5000 gpm) Rated Pressure (40-200 net psi) Rated Speed
Permissible Performance Ranges
Allows maximum 140% rated net pressure at churn (no flow)
Requires a minimum of 65% rated net pressure at 150% of rated flow (max. flow)
Pump Sizing
Calculate system demand to pump discharge flange
Calculate water supply to pump suction flange Select pump so that the system flow demand is
less than 150% of the rated flow of the pump (less than 140% recommended)
Pump Sizing Using the Manufacturers Pump Curve, find the
pump’s net pressure at the system demand flow Add the suction pressure (at demand flow) to
the net pressure (at demand flow) to get the discharge pressure (at demand flow)
If the discharge pressure is greater than the demand, okay. If not, select new pump.
Fire Pump Sizing
Advantages of Specific Model Sizing– Know exactly how the pump will perform– Match pump’s performance to system demands– Capable of predicting maximum pressure
Disadvantages to Specific Model Sizing– Not always possible to know system demand– Not always possible to know which model pump will be
used in the conceptual stages of design
Alternative Method for Specifying Fire Pump Size
Estimate fire protection system demand at pump discharge flange
Assume a pump with a specific rated flow and pressure– Assume that the pressure will not increase at flows
less than the rated flow– Assume that the pump will perform to the minimum
point of 65% of rated pressure at 150% of rated flow Perform Specific Model Analysis Later
Alternative Method for Specifying Fire Pump Size
0 20 40 60 80 100 120 150Flow (% of Rated Flow)
140
20
50
80
110
Pre
ssur
e (%
of
Rat
ed P
ress
ure)
Minimum Pressures Produced by Pump
Maximum Pressure Produced by Pump
Pump House/Pump RoomNFPA 20 requires protection from: Explosion and fire Flood and earthquake Rodents and insects Windstorm and freezing Vandalism Other adverse conditions
Pump House/Pump Room
Pump House– Construction– Separation
Pump Room– Separation– Accessibility
Pump House / Pump Room Size - fit pump, equipment, and suction
pipe Heat - at least 40° F (more for diesel) Ventilation Light - artificial and emergency Drainage - size and pitch
Suction Pipe
Straight run to suction flange Vertical bend into suction flange Horizontal bend into suction flange
Suction Pipe Size The size of the suction pipe . . . shall be such
that . . . At 150% of rated capacity, the gage pressure at the pump suction flange shall be 0 psig or higher. (Note: Pressure is allowed to go as low as -3 psig for tanks on same level as pump)
The size of that portion of the suction pipe located within 10 pipe diameters upstream of the pump suction flange shall be not less than that specified in Table 5-25(a) or (b).
Suction Pressure
Must be positive Evaluate at maximum flow of pump
(150% of rated flow) Take into account friction loss of all pipe
and components between water supply and pump
Take into account elevation between water supply and pump
Suction Pressure Calculation
Find the residual pressure of the water supply at the maximum flow for the pump (150% of rated flow). Call this PR.
Calculate all pressure losses (friction and elevation) between the water supply and the pump suction flange at maximum flow for the pump. Call this PL.
The Suction Pressure will be the residual pressure from the water supply minus the pressure losses.
PS = PR - PL
Suction Pressure CalculationExample
1500 gpm pump
Suction Pressure Calculation
Suction Pressure Calculation
Analysis at 2250 gpm (150% of 1500) Residual Pressure = 24 psi (from graph) Friction loss through underground = 2.4 psi Friction loss in pump room piping = 1.2 psi Friction loss through backflow = 8.0 psi Elevation loss = 0.0 psi PS = 24 - 2.4 - 1.2 - 8.0 - 0.0 = 12.4 psi
Design / Installation of Suction Pipe
NFPA 24 Air Pockets Air Leaks Eccentric Reducers Protection from Freezing Hydrostatic Testing Screens (Open Water Source)
Reducers
Devices in Suction Pipe Control Valves Check Valves Vortex Plates Low Pressure Cut-off Devices Low Pressure Throttling Devices By-Pass Piping Backflow Preventers
Discharge Piping
Steel - Rated for Maximum Working Pressure
Maximum Working Pressure = Static Pressure + (Net) Churn Pressure
Devices in Discharge Piping Control Valve Check Valve Pressure Relief Valve - only required if
discharge pressure exceeds components’ ratings (evaluate at component)
Circulating Relief Valve– Required for electric driven pumps– Required for diesel driven pumps with radiator
cooling
Discharge Pipe and Components
Fire Pump PressureRelief Valves
Pressure ReliefValve
Fire Pump CirculationRelief Valves
Circulationrelief valve
Testing Arrangements
Test Header to Open Flow to Reservoir Closed Loop Metering
Test Headers Listed Outlets (Table 2-20) Location Shut-off Valve (if needed) Drain Pipe Size (Table 2-20)
Determining Flow Pitot Gage
Flow Meter– Listed– 175% of Rated Flow– Size (Table 2-20)
Pitot Gage
Converting Pitot to FlowQ=29.83 c d2 P
Q = flow in gpm
c = 0.97
d = nozzle diameter in inches
P = Pitot pressure in psi
Sensing Lines Connected between discharge check
valve and control valve Separate for each pump Minimum 1/2” corrosion resistant pipe Check valves/Ground Face Unions
Pressure Sensing Line Connections
Valve SupervisionControl Valves
Suction, Discharge, By-Pass, Test Outlet
1. Central station, proprietary, or remote signaling service.
2. Local signaling service providing an audible signal at constantly attended location.
3. Locking valves open.
4. Sealing of valves in a fenced enclosure
NFPA 25
Inspection, Testing and Maintenance of Water Based Fire Protection
Systems
Weekly Inspection of
Pump Components
Pump House
Adequate Heat
Ventilating Louvers Operational
Hydraulic Systems
Suction & Discharge Valves Open
Suction Pressure Gage Normal
System Pressure Gage Normal
Reservoir Full
Electrical SystemsController Power “on”
Transfer Switch “normal”
Isolating Switch Closed
Reverse Phase Light off
or
Normal Phase Light on
Diesel EnginesFuel Tank 2/3 Full
Controller in “Auto” position
Battery Voltage Normal
Charger Readings Normal
Battery Pilot Lights on
or
Failure Lights off
Alarm Lights off
Engine Run Time Meter Reading
Oil Level Normal
Crank Case Oil Level Normal
Cooling Water Level Normal
Electrolyte level (batteries) Normal
No Corrosion on Battery Terminals
Water-jacket Heater Operating
Weekly Tests (No Flow)
Automatic Start
Electric Pumps - 10 minutes
Diesel Drivers - 30 minutes
Record During TestSuction & Discharge Pressures
Slight Discharge from Packing Gland
No Unusual Noise or Vibrations
No Overheating
Pump Starting Pressure
Time to Achieve Full Speed
Time Controller on First Step
Suction Pressure Discharge Pressure
Time Pump Runs After Starting
(for Auto-Stop Controllers)
Time for Engine to Crank
Time to Reach Run Speed
Engine Oil Pressure, Speed, Water and Oil Temperature
Water Flow in Heat Exchanger
Annual Flow Test
No Flow
Rated Flow
Peak Flow
Test OptionsTest Header to Hose Streams
Flow Meter to Drain or Suction Reservoir
Closed Loop Metering
At Churn
Check Circulation Relief Valve
Check Pressure Relief Valve
Run Test for 30 minutes
At Flow ConditionsRecord Voltage & Current
Record Pump RPM
Record Suction & Discharge Pressures
Record Flow
Observe Alarm Operations
Testing Equipment
Pressure Gages
Tachometer
Ammeter
Hose & Playpipes
Pitot Tube
Flow Meter
Converting Flow to Pitot
Q = flow in gpm
c = 0.97
d = nozzle diameter in inches
P = Pitot pressure in psi
2
283.29
cd
QP
Test Procedure - for Test Header and Hoses
1. Water at test header (all air out of system)
2. Start the pump
3. General pump operation
No unusual vibrations, noises, oil or water leaks
4. Check packing gland
5. At churn (no flow into system), record:
Suction Pressure, Discharge Pressure, RPM
Amperes & Volts (if applicable)
6. Open test header valves
Achieve 100% of rated flow
7. At rated flow, record:
Suction Pressure, Discharge Pressure
RPM, Pitot Gage Readings (if applicable), Amperes & Volts (if applicable)
Test Procedure - for Test Header and Hoses (continued)
8. Open test header valves to achieve 150% of rated flow
9. Record data at 150% of rated flow
Test Procedure - for Test Header and Hoses (continued)
10. Calculate pump net pressures
11. Plot flow curve
12. Compare flow curve to manufacturers shop curve
13. Plot ampere curve (electric motor)
14. Compare ampere curve to manufacturers curve
Test Procedure - for Test Header and Hoses (continued)
Test Procedure - for Flow Meters
1. Prime pump (get all air out)
2. Discharge valve closed
3. Start the pump
4. General pump operation
No unusual vibrations, noises, oil or water leaks
5. Check packing gland
6. At churn (no flow in system), record:
Suction Pressure, Discharge Pressure, RPM
Amperes & Volts (if applicable)
7. Open (flow meter) to achieve 100% of rated flow
8. At rated flow, record:
Suction Pressure, Discharge Pressure, RPM
Pitot Gage Readings (if applicable), Amperes & Volts (if applicable)
Test Procedure - for Flow Meters
9. Open the flow meter valve to achieve 150% of rated flow
10. Record data at 150% of rated flow
11. Calculate pump net pressures
12. Plot flow curve
13. Compare flow curve to manufacturers
14. Plot ampere curve
15. Compare ampere curve to manufacturers
Test Procedure - for Flow Meters
Activate Suction Throttling Valve
Simulate Power Failureif Transfer Switch Installed
Alarm Sensors&
Indicating Devices
Pump Test Data
Test
100%
Churn
150%
Driver Suction Pressure Net Nozzle Flows TotalSpeed Discharge Size Pito/Flow Flow
RPM psi psi psi Inches 1 2 3 4 gpm
Q = 29.83 X D X C X P2 VC = .97
1700 16 125 N/A 0 0 0 0 0
60 601690 16 110 1 3/4
35 37 48 481675 16 85 1 3/4
Pump Test Data
Test
100%
Churn
150%
Driver Suction Pressure Net Nozzle Flows TotalSpeed Discharge Size Pito/Flow Flow
RPM psi psi psi Inches 1 2 3 4 gpm
Q = 29.83 X D X C X P2 VC = .97
1700 16 125 109 N/A 0 0 0 0 0
60 601690 16 110 94 1 3/4 686 686 1372
35 37 48 481675 16 85 69 1 3/4 524 539 614 614 2291
Adjustment Formulas
Q’ = Q(Rated Speed/Test Speed)
PN’ = PN(Rated Speed/Test Speed)2
Q’ = 0(1760/1700) = 0 gpm
P’=109(1760/1700)2 = 117 psi
Q’ = 1372(1760/1690) = 1429 gpm
P’ = 94(1760/1690)2 = 102 psi
Q’ = 2291(1760/1675) = 2407 gpm
P’ = 69(1760/1675)2 = 76 psi
Thank You!