Water Sizing

Plumbing Systems

CNST 305 Environmental Systems 1Dr. Berryman

3c Water System Chapter 8; Appendix B (Wentz) and 8.1-  8.3 (Toa)

4.11 Analysis and Design of Construction Systems - Mechanical (6 hrs)

Steps to sizing

Isometric Diagram

30o

Assign WSFU Water Supply Fixture Unit (WSFU)

• • •

Use Table 2-2 (Wentz) for WSFU assignment…pp 7-12 See note 3 (fine print on bottom)

2 WSFU x .75 = 1.5

5 WSFU

10 WSFU1 ¼” spud

Add Up All WSFU

1.5 WSFU

1.5 WSFU

1.5 WSFU

1.5 WSFU

5 WSFU

5 WSFU

10 WSFU

10 WSFU

3 WSFU

8 WSFU

13 WSFU

23 WSFU

33 WSFU

3 WSFU

21 WSFU

110 WSFU

24 WSFU

143 WSFU

Convert to GPM

5 GPM

14.6 GPM

16.4 GPM

5 GPM

3.5 GPM for each

10 GPM

29.4 GPM

36.8 GPM42.7 GPM

78.3 GPM

70 GPM

7 GPM

7 GPM

27 GPM

27 GPM

Hunter CurvesPredominantly Flushometer

Predominantly Flush Tank

Select Chart and Size

Note:

•Use copper pipe

•Use minimum size from tbl 2.2 for individual fixture pipe

½”

½”½”

½”

¾”

¾”

1”

1”

1 ¼” spud

Predominantly Flushometers for Smooth Copper Pipe

5 gpm10 gpm

42.7 gpm

29.4 gpm36.8 gpm

70 gpm78.3 gpm

Notes:

• 5-10 fps

• 2-7 psi/100’

¾”1”

1½”1½”

2”2”

2 ½”

Class Exercise You size the hot water piping Does the hot water side use

flushometers? Use predominately flush tanks

Check

1 ¼”

¾”

1”

¾”

1”

1 ½”

1 ½” 2”

2 ½”

2”

½”

½”½”

½”

¾”

¾”

1”

1”

• 5-10 fps

• 2-7 psi/100’

•Pressure at last fixture

Notable notes: Booster pumps

Need for boost water pressure to overcome static head and friction

Sizing• (A) Available water pressure• (B) Pressure required at last fixture• (C) Static head losses• (D) Friction losses

• Equivalent length• Pressure drop through backflow preventors, meter,

water softeners, and filters A – (B+C+D) = required boost

Next Time Assignment #1

Due Monday beginning of class• Problem 9 in Chapter 8 of Wentz, pp. 132

Drain Waste Vents (DWV)

4abc Drain, Waste, Vent Chapter 2,5,6 Appendix C (Wentz) and  8.4 - 8.5 (Toa)