Sizing DWV

1
Sizing DWV

• Plumbing Systems
• CNST 305
• Environmental Systems 1
• Dr. Berryman

2
Design Guidelines

• VENTS
• Above ground venting cannot be less than 1 ¼
• 1 ¼ vent can handle on 1 DFU
• Underground venting cannot be less than 2 in
  diameter
• Vents must be a certain distance from the trap
  that it serves
• An individual vent must not be less than ½ the
  size of the drain that it connects
• An individual vent should not be larger than the
  drain that it connects
• Downstream piping always bigger than the upstream
  section
• A vent line must be 6 above flood level rim of
  the fixture before turning horizontal
• Branch vents must slope toward a drain
• Some codes require that at least one of the
  buildings VTR be 4 in diameter or larger

• DRAIN/WASTE
• All traps must be vented
• The waste stack cannot be smaller the the largest
  horizontal branch connecting to the stack
• At least one waste stack same as building drain
• No branch pipe smaller than the one that proceeds
  it
• Above ground cannot be less that 1¼
• Below ground cannot be less than 2
• 1 ¼ drain pipe can handle on 1 DFU
• A drain line cannot be smaller than the trap arm
  to which it is connected
• Use 4 trap arm for floor mounted water closets

3
Sizing Drain Waste

• Determine number of plumbing fixtures to install
• Layout fixtures in space to codes (ie ADA)
• Determine site utilities
• Generate isometric
• Determine minimum trap size for each fixture (tbl
  2-2)
• Determine DFU
• Add DFU values starting from the farthest end of
  system

4
Drain/Waste Iso

• GIVEN
• Water Closet Siphon jet w/ flushometer valve,
  pressure 15 psi
• Wall Urinal Siphon jet with ¾ spud/flushometer
• Lavatory
• TDL 100

5
Determine Trap Size for Drains

• From Table 2-2
• Water Closet 3
• Wall Urinal 2
• Lavatory 1 ¼

6
Add DFU

• Water Closet 6 DFU
• Wall Urinal 4 DFU
• Lavatory 1 DFU

7
Size Waste Branches
8
Sizing Waste (cont.)
9
Sizing Vents
10
Complete DWV Isometric
11
Sizing Circuit or Loop Vents
12
Next Time

• Test Review
• In class homework assignment
• Review notes and reading
• Able to use books/notes
• Due 10 minutes before end of class
• We will grade and review assignment
• Next week Start HVAC

13

• GIVEN
• Water Closet Siphon jet w/ flushometer valve,
  pressure 15 psi
• Wall Urinal Siphon jet with ¾ spud/flushometer
• Lavatory
• TDL 100