Water Storage Tank Sizing Lab
Work out daily water use from the occupants, choose how many days to store and how to split it between ground and roof tanks, then size each tank and its compartments. Check the mains connection can refill it, how long water sits in the tank, and watch the levels rise and fall through a day.
How to use: pick the building type and occupancy. Daily use figures are typical design values you can change. Tap i for explanations.
1. Occupancy and storage
Domestic water only. Fire water is sized in FF-203.
2. Tanks
Ground (break) tank, transfer pumps and roof tank with compartments.
3. Checks
4. Tank schedule
5. How it works
Daily demand
Daily use is occupants × litres per person per day, plus irrigation, cooling tower make-up or other process water. Gulf design figures are high because of climate and lifestyle: 200 to 300 L per person per day for apartments is common.
Days of storage and the split
Many Gulf authorities and specifications ask for about one day of storage to ride through supply interruptions. Part is held in a ground or basement break tank and part in a roof tank that feeds the upper floors by gravity or the booster sets.
Water quality
Water that sits too long loses its chlorine residual and warms up, which encourages bacteria such as Legionella. Aim to turn the tank over in no more than about 24 to 48 hours, keep the tank shaded and insulated, and use two compartments so one can be cleaned while the other stays in service.
Refill
The mains connection must refill the daily demand within the hours the supply is available. The lab sizes the connection pipe for that flow at your velocity limit.
Learning and checking tool. Storage days, compartments and tank materials must follow your authority, for example DEWA or ADDC connection rules and the Dubai Building Code.