EAT 237 WATER SUPPLY ENGINEERING Water Distribution 2

EAT 237 WATER SUPPLY ENGINEERING Water Distribution 2: Water Conveyance Fahmi Muhammad Ridwan SCHOOL OF ENVIRONMENTAL ENGINEERING UNIVERSITI MALAYSIA PERLIS 2016

Water Conveyance system Objective : To provide a conduit to move water from the raw water intake to the treatment plant and from the treatment plant to the point of use. Types of Conveyance System - Open Channels: Canals, Flumes and Aqueducts, Gravity Conduits, Grade Tunnels - Pressure Conduit

Hydraulics Considerations For Open Channel: Manning Equation For Pressure Conduits: Hazen-Williams Equation In U. S customary Unit:

The coefficient Ch is dependent only on the condition of the surface of the pipe or conduit. Table 8. 3 gives typical values Type of Pipe Ch Average for New, Clean Pipe Design Value

The Hazen–Williams formula for SI units is

Other types of calculations that are often desired are: 1. To determine the required size of pipe to carry a given flow rate while limiting the energy loss to some specified value. 2. To determine the energy loss for a given flow rate through a given type and size of pipe of a known length. The following table shows several forms of the Hazen–Williams formula that facilitate such calculations.

Nomograph for solving the Hazen-Williams Formula • • The nomograph shown in the following figure allows the solution of the Hazen–Williams formula to be done by simply aligning known quantities with a straight edge and reading the desired unknowns at the intersection of the straight edge with the appropriate vertical axis. Note that this nomograph is constructed for the value of the Hazen–Williams coefficient of Ch = 100.

Example 1 For what velocity of flow of water in a new, clean, 6 -in Schedule 40 steel pipe would an energy loss of 6. 1 m of head occur over a length of 304. 8 m? Compute the volume flow rate at that velocity. Then refigure the velocity using the design value of Ch for steel pipe. Example 2 Specify the required size of Schedule 40 steel pipe to carry 0. 034 m 3/s of water with no more than 4. 0 m of head loss over a 1000 m length of pipe. Use the design value for Ch.

Tutorial Question 1 Water flows at a rate of 0. 042 m 3/s through 167. 64 m of 6 in cement line ductile iron pipe. Compute the energy loss Tutorial Question 2 Compute the energy loss as water flows in a 4 -in type K copper tube at a rate of 1000 L/min over a length of 45 m. Tutorial Question 3 A fire protection system includes 457. 2 m of 10 -in schedule 40 steel pipe. Compute the energy loss in the pipe when it carries 5677. 5 L/min of water Tutorial Question 4 A 4 -in type K copper tube carries 900 L/min of water over length of 80 m. Compute the energy loss.

Tutorial Question 5 Specify the suitable size of new, clean schedule 40 steel pipe that would carry 1135. 5 L/min of water over a length of 365. 76 m with no more than 3. 05 m of head loss. For the selected pipe, compute the actual expected head loss. Tutorial Question 6 For the pipe selected in Question 5, compute the head loss using the design value for Ch rather than that for new, clean pipe. Tutorial Question 7 Compute the head loss that would result from the flow of 378. 5 L/min of water through 304. 8 m of new, clean schedule 40 steel pipe for 2 -in and 3 -in sizes.