Section 675IAC15-2-39. Traps

   (a) Traps Required. Each plumbing fixture, except listed toilets shall be separately trapped by approved water seal "P" traps. All traps shall be effectively vented.

  (b) Dual Fixtures. A two-compartment sink, two single sinks, two lavatories, or a single sink and a single lavatory with waste outlets not more than thirty inches (30") apart and in the same room and flood level rims at the same level may be connected to one "P" trap and may be considered as a single fixture for the purpose of drainage and vent requirements.

  (c) Prohibited Traps. A trap which depends for its seal upon concealed interior partitions shall not be used. Full "S" traps, bell traps, drum traps, crown-vented traps, and running traps are prohibited. Fixtures shall not be double-trapped.

  (d) Material and Design. Each trap shall be self-cleaning with a smooth and uniform interior waterway. Traps shall be manufactured of cast iron, cast brass, or drawn brass tubing of not less than No. 20 Brown and Sharpe gauge, or approved or listed material. Union joints for a trap shall be beaded to provide a shoulder for the union nut. Each trap shall have the manufacturer's name stamped or cast in the body of the trap, and each trap shall show the gauge of the tubing.

  (e) Trap Seal. Each "P" trap shall have a water seal of not less than two inches (2") and not more than four inches (4") and shall be set true to its seal.

  (f) Size. Traps shall be not less than one and one-fourth inches (1 1/4") in diameter. A trap shall not be larger than the waste pipe to which it is connected.

  (g) Location. Each trap shall be located as close to its vent and to its fixture outlet as structural conditions will permit.

  (h) Length of Tailpiece. The vertical distance from a trap to the fixture outlet shall not exceed twenty-four inches (24").

  (i) Installation shall be as follows:

(1) Grade of Trap Arm. The piping between a "P" trap and the fixture tee or the vented waste line shall be graded one-fourth inch (1/4") per foot towards the vent and in no event shall have a slope greater than its diameter. The vent opening at fixture tees shall not be below the weir of the "P" trap outlet.

(2) Trap Arm Offset. The piping between the "P" trap and vent may change direction or be offset horizontally with the equivalent of no more than one hundred eighty degrees (180°).

(3) Concealed Traps. Traps with mechanical joints shall be accessible for repair and inspection.

(4) Removability of Traps, Etc. Traps shall be designed and installed so the "U" bend is removable without removing the strainers from the fixture. Continuous waste and tailpieces which are permanently attached to the "U" bend shall also be removable without removing the strainer from the fixture.

(Fire Prevention and Building Safety Commission; 675 IAC 15-2-39; filed Mar 25, 1986, 1:44 pm: 9 IR 1993, eff Jun 15, 1986; readopted filed Nov 29, 2001, 12:21 p.m.: 25 IR 1306; readopted filed Sep 21, 2007, 9:20 a.m.: 20071010-IR-675070388RFA; readopted filed Oct 10, 2007, 9:16 a.m: 20071031-IR-675070388RFA; readopted filed Aug 4, 2011, 8:35 a.m.: 20110831-IR-675110254RFA)