How to quickly estimate the flow rate of water supply equipment?

Water supply equipment flow rate estimation. Knowing the number of households in a community, a relatively accurate flow rate parameter can be obtained by adjusting the number of occupants and water consumption standards. Based on the user's actual situation and understanding of the project's number of water users and housing types, the required flow rate for the project can be roughly calculated. The calculation formula is as follows:

Q=（m×q÷t）×K

m——Number of water users (generally 4-5 people per household)

q——Water consumption standard (national standard 180 liters/day. South China 300 liters/person.day; high-end residential areas use 400 liters/person.day)

t——Water consumption time (generally 12 hours/day)

K——Variation coefficient (generally 1.5-2.5)

The unit obtained at this time is liters /hour (L/h), after dividing by 1000, the unit becomes m3/h

For example: A city community has 5 fifteen-story buildings, with 3 households per floor, a building height of 67 meters, a tap water pipe pressure of 0.2-0.35 MPa, and a municipal engineering water pipe diameter of DN250. What is the maximum water supply capacity of this community?

Through calculation, the coefficients in the formula are:

Number of water users m = Total number of households × Number of people per household = 3 × 15 × 5 × 4 people/household = 900 people

Water consumption standard q = 250 liters/day = 0.25 m3/d

Water consumption time t = 12d

Variation coefficient K = 2.5

Substitute the parameters into the formula to calculate the maximum flow rate: Q = 900 × 0.25 ÷ 12 × 2.5 = 47 m3/h

Note 1: The flow rate calculated by the formula is relatively small, but the calculation result is more in line with the actual situation. The margin can be appropriately increased according to the owner's requirements and the parameters on the water supply and drainage drawings.

Note 2: The selection of water pumps should be based on the size of the flow rate to determine the reasonable number of water pumps. Usually, the number of water pumps is 2-4. For a one-in-one-out system, water treatment manufacturers generally suggest adjusting to two-in-one-out or adding auxiliary pumps when the single pump power exceeds 11KW, in order to reduce power consumption during low-flow operation!