Ensure Adequate Flow Rates at Appliances by Correct Pipe Sizing

ENSURE ADEQUATE FLOW RATES AT APPLIANCES BY CORRECT PIPE SIZING

Water is a basic need for life is likely to outshine many activities during the 21^thcentury. buildings need correct water supply system which provides and distributes water to different parts of the building for the purposes such as drinking, cleaning, washing, culinary use, it includes the water distributing pipes, control devices, equipment, and other appurtenances.

Pipe Sizing Procedures for Supply Mains

Pipe Sizing Consideration

(Source: Garrett, R. H., 2008. Hot and Cold Water Supply)

1. Assume a pipe diameter.

2. Determine the flow rate:

a. by using loading units;

b. for continuous flows;

c. obtain the design flow rate by adding (a) and (b).

3. Determine the effective pipe length:

a. work out the measured pipe length;

b. work out the equivalent pipe length for fittings;

c. work out the equivalent pipe length for draw-offs;

d. obtain the effective pipe length by adding (a), (b) and (c).

4. Calculate the permissible loss of head:

a. determine the available head:

b. determine the head loss per meter run through pipes;

c. determine the head loss through fittings;

d. calculate the permissible head loss.

5. Determine the pipe diameter:

a. decide whether the assumed pipe size will give

Equivalent pipe length
Equivalent pipe length Is the expression of friction resistances to flow through valves and fittings in terms of pipe lengths having the same resistance to flow as the valve or fitting.

For example, a 20 mm elbow offers the same resistance to flow as a 20 mm pipe 0.8 m long.

Effective pipe length. The effective pipe length is the sum of the measured pipe length and the equivalent pipe lengths for fittings and draw-offs.