1. Technology in Architecture
Lecture 15
Waste & Vent Systems
Waste & Vent Sizing Procedure

2. Waste & Vent Systems

3. Fundamentals Siphon action can drain water Trap blocks sewer gas
Vent breaks siphon
M: p. 1006, F.22.8

4. Air Gaps Eliminate the potential for cross contamination
M: p. 1009, F.22.11

5. Bathroom Design Considerations
ADA compliance
ANSI Standard A
Wheel chair access
Grab bars
Counter top/fixture heights
Visual privacy
Acoustical privacy

6. Vents and Stacks Circuit vents Soil stack Vent stack Stack vent
Note: Drain fittings are 45º
Individual vents
Circuit vents
Soil stack
Vent stack
Stack vent
“Wet stack”
Vent through roof (VTR)
M: p. 1008, F.22.10

7. Drains & Sewers House sewer Storm drain Clean outs House traps
Note: Drain fittings are 45º
House drain
House sewer
Storm drain
Clean outs
House traps
Fresh air inlet
M: p. 1007, F.22.9

8. Waste & Vent Sizing Procedure

9. 1. Identify waste & soil locations
Clusters are more efficient
M: p. 1014, F.22.17

10. 2. Layout system vertically & horizontally
Grouped fixtures can be stacked in a vertical riser
M: p. 1027, F.22.31

11. 3. Size Traps Trap size is used when connecting to main
M: p. 1017, T.22.2

12. 4. Calculate Drainage Fixture Units (DFU)
Pipe sizes based on DFU
M: p. 1017, T

13. 5. Determine loads Fixture location may control size M: p. 1022,

14. 6. Determine slope and size of horizontal drains
Slope may be constrained by depth of floor cavity
M: p. 1020, T.22.5

15. 7. Verify maximum vent length
Measured from plans
M: p. 1022,
F.22.24

16. 8. Size vents according to DFU and length
Calculate for each vent load and developed length
M: p. 1019, T.22.4

17. 9. Verify space requirements and adjust design
Common adjustments
“Wet” walls  6” cavity
Slope and ceiling exposure
Cleanout access