18-29-709.1 Values for fixtures.

   Drainage fixture unit values as given in Table 18-29-709.1 designate the relative load weight of different kinds of fixtures that shall be employed in estimating the total load carried by a soil or waste pipe, and shall be used in connection with Tables 18-29-710A and 18-29-710B of sizes for soil, waste and vent pipes for which the permissible load is given in terms of fixture units.

Table 18-29-709.1
Drainage Fixture Units for Fixtures and Groups

Fixture Type	Drainage Fixture Unit Value as Load Factors	Minimum Size of Trap (inches)
Automatic clothes washers, commercial a	3	2
Automatic clothes washers, residential	2	2
Bathroom group consisting of water closet, lavatory, bidet and bathtub or shower	6	–
Bathroom b (with or without overhead shower or whirlpool attachments)	2	1 1/2
Bidet	2	1 1/4
Combination sink and tray	2	1 1/2
Dental lavatory	1	1 1/4
Dental unit or cuspidor	1	1 1/4
Dishwashing machine, c domestic	2	1 1/2
Drinking fountains	1/2	1 1/4
Emergency floor drain	0	2
Floor drains	2	2
Kitchen sink, domestic	2	1 1/2
Kitchen sink, domestic with food waste grinder and/or dishwasher	2	1 1/2
Laundry tray (1 or 2 compartments)	2	1 1/2
Lavatory	1	1 1/4
Shower compartment, domestic	2	2
Sink	2	1 1/2
Urinal	4	Footnote d
Urinal, 1 gallon per flush or less	2 e	Footnote d
Wash sink, (circular or multiple) each set of faucets	2	1 1/2
Water closet, flushometer tank, public or private	4 e	Footnote d
Water closet private installation	4	Footnote d
Water closet public installation	6	Footnote d

 

For SI: 1 inch = 25.4 mm, 1 gallon = 3.785L.

a For traps larger than 3 inches, use Table 709.2.

b A showerhead over a bathtub or whirlpool bathtub attachments does not increase the drainage fixture unit value.

c See Section 709.2 for methods of computing unit value of fixtures not listed in Table 709.1 or for rating of devices with intermittent flows.

d Trap size shall be consistent with the fixture outlet size.

e For the purpose of computing loads on building drains and sewers, water closets or urinals shall not be rated at a lower drainage fixture unit unless the lower values are confirmed by testing.