Hydraulic Calculations for Water Storage Tank

HYDRAULIC CALCULATIONS FOR WATER STORAGE TANK

DM Water

Storage Tank Service Manhole

Vent

Freefloat, L8

Overflow nozzle

Top Capacity Level (TCL) - L7 High High Level (HHL) - L6 High Level (HL) - L5 Normal Level (NL) - L4

Working Capacity

Low Alarm (LA) - L3

Parameters Nominal Tank Diameter, D

UOM feet

Value 26.00

Silt allowance, L0

inch

0

Largest size of nozzle in bottom plate Bottom Capacity Level, L1 Top of Lowest Suction Nozzle Low Low Trip, L2 Low Alarm, L3 Working Capacity / Usable volume

inch inch inch inch inch gal

4 6 10 16 22 75,000

Top Capacity Level, L7

inch

233

Size of overflow nozzle Freefloat level, L8 High High Level, L6 High Level, L5 Normal level, L4 Tank Height (H) Adjusted Height H/D ratio Max. inflow Max. outflow Residence time between HL to LLT Dead storage Reserved fire water storage Max. fire water demand Volume available for non-fire users

inch inch inch inch inch feet feet

4 244 227 221 177 20.37 21 0.78 500 400 169 1,980 55,116 2,239 16,584

gpm gpm min gal gal gpm gal

Remark Check site limitations, Note-2

Minimum 4 inch, only recommended for tanks storing suspended solids

Note-3 Check site limitations, Note-2 Should be between 0.6 to 0.8, Note-1

Note-5 Note-4 Between Normal and Hi-Hi level

Input Cells Low Low Trip (LLT) - L2 TOP OF LOWEST SUCTION NOZZLE Pump Suction nozzle

Bottom Capacity Level (BCL) - L1 Drain

Silt Allowance (SL) - L0

Notes 1) H/D ratio shall be maintained 0.6 to 0.8 for reservoirs and 1 to 4 for standpipe 2) Check maximum allowable nominal diameter (D) and height (H) per site conditions 3) For combined fire / service water tank, normal level is replaced by reserved fire water level 4) Resolve all "RED" cells, except fire water storage for non-fire water tanks 5) If inflow is more than outflow, residence time is with inflow closed