System Sizing Worksheet
Instructions: Follow steps 1,2 and 3 to select the proper water pressure booster systems.
STEP 1
Since municipal water pressure is often sufficient to handle the needs of many buildings, first determine if a water pressure booster system is required.
Project Criteria | PSI |
A. Pressure required at the highest outlet | |
B. Pump Package Inlet (Elevation in feet) | |
B. Static Head from Pump Package Inlet (Elevation in feet x .433psi/ft) | |
C. Piping friction loss (Estimate 10% of static head in PSI) | |
D. Pressure loss through building system components such as water filters. softeners, etc. | |
E. Required building system pressure ( Add A+B+C+D) | |
F. Subtract the minimum suction pressure at the pump ( The minimum pressure after water meter and backflow preventer | |
G. Total (E minus F) | |
H. Add internal water booster pressure loss (5 psig) | |
I. Required pump differential pressure “Boost” (G+H) |
Fixture Flow Units
STEP 2
Instructions: Use this table to determine peak flow capacity. Do not include fixtures not serviced by the water pressure booster system.
Fixture | Occupancy | Load in Fixture Units | x | Number of Fixtures | Total |
Bathroom Group F.V. * | Private | 8 | x | ||
Bathroom Group F.T.* | Private | 6 | x | ||
Water Closet F.V.* | Public | 10 | x | ||
Water Closet F.T* | Public | 5 | x | ||
Urinal-Stall or Wall | Public | 5 | x | ||
Lavatory | Public | 2 | x | ||
Bathtub | Public | 7 | x | ||
ShowerHead Each ** | Public | 7 | x | ||
Kitchen Sink | Public | 7 | x | ||
Service Sink | Public | 3 | x | ||
Clothes Washer | Private | 2 | x | ||
Clothes Washer | Public | 4 | x | ||
Dishwasher | Public | 2 | x | ||
Drinking Fountain | Public | 2 | x | ||
3/4″ Connection | Public | 6 | x | ||
Total Flow Fixture Units = |
System GPM Load
STEP 3
Instructions: After determining the total fixture flow units, convert to gallons per minute load(GPM).
Fixture Flow Units | School,Office,Apt. GPM | Hotel GPM | Hospital GPM |
100 | 70 | 80 | 100 |
300 | 80 | 90 | 100 |
600 | 100 | 100 | 120 |
900 | 120 | 125 | 135 |
1200 | 135 | 145 | 155 |
1500 | 150 | 165 | 185 |
1750 | 170 | 185 | 200 |
2000 | 190 | 200 | 220 |
3000 | 250 | 275 | 300 |
4000 | 300 | 340 | 365 |
5000 | 350 | 400 | 430 |
6000 | 400 | 450 | 490 |
7000 | 450 | 500 | 540 |
8000 | 490 | 550 | 600 |
Table No. 3
Required System GPM: | |
Planned “Added Service”: | |
Total Peak Load GPM: |
Added Service – Flow required for any special duty such as future expansion, irrigation systems, and cooling tower evaporation make up (Use (1) GPM per 20 tons cooling).
Laundries – In the case of hotels and hospitals, where a laundry is operated, increase the total pumping
capacity by 10%.