Section P3004 Determining Drainage Fixture Units
The load on DWV-system piping shall be computed in terms of drainage fixture unit (d.f.u.) values in accordance with Table P3004.1.
DRAINAGE FIXTURE UNIT (d.f.u.) VALUES FOR VARIOUS PLUMBING FIXTURES
|TYPE OF FIXTURE OR GROUP OF FIXTURES||DRAINAGE FIXTURE UNIT VALUE (d.f.u.)a|
|Bathtub (with or without a shower head or whirlpool attachments)||2|
|Clothes washer standpipe||2|
|Water closet (1.6 gallons per flush)||3|
|Water closet (greater than 1.6 gallons per flush)||4|
|Full-bath group with bathtub (with 1.6 gallon per flush water closet, and with or without shower head and/or whirlpool attachment on the bathtub or shower stall)||5|
|Full-bath group with bathtub (water closet greater than 1.6 gallon per flush, and with or without shower head and/or whirlpool attachment on the bathtub or shower stall)||6|
|Half-bath group (1.6 gallon per flush water closet plus lavatory)||4|
|Half-bath group (water closet greater than 1.6 gallon per flush plus lavatory)||5|
|Kitchen group (dishwasher and sink with or without food-waste disposer)||2|
|Laundry group (clothes washer standpipe and laundry tub)||3|
|Multiple-bath groupsc: |
For SI: 1 gallon = 3.785 L, 1 gallon per minute = 3.785 L/m.
- For a continuous or semicontinuous flow into a drainage system, such as from a pump or similar device, 1.5 fixture units shall be allowed per gpm of flow. For a fixture not listed, use the highest d.f.u. value for a similar listed fixture.
- A floor drain itself does not add hydraulic load. Where used as a receptor, the fixture unit value of the fixture discharging into the receptor shall be applicable.
- Add 2 d.f.u. for each additional full bath.