Fixture Trap Vents

Section 890 Section 890.1470  Fixture Trap Vents a)         Distance of Trap From Vent.  Each fixture trap shall have a protecting vent located so that the developed length in the fixture drain from the trap weir to the vent fitting is within the requirements in Appendix A.Table I. (See Appendix K.Illustration L.) b)         Trap Weir.  The vent pipe opening from a soil or waste pipe, except for water closets or fixtures with an integral trap, shall not be below the trap weir.  (See Appendix K.Illustration N.) c)         Crown Vent. No trap vent shall be installed within two pipe diameters of the trap weir.  (See Appendix K.Illustration M.) d)         Hydraulic Gradient. Fixture drains shall be vented within the hydraulic gradient between the trap outlet and the junction with another drain.  The hydraulic gradient as applied to a gravity drain and its corresponding vent connection is interpreted as the grade line.  (See Appendix A.Table I and Appendix K.Illustration N.) e)         Different Level. If any stack has fixtures entering at different levels, the fixtures other than the fixtures entering at the highest level shall be vented in accordance with Section 890.1420(b). f)         Fixture Trap Protection.  Each fixture trap shall be protected by the appropriate method as follows:  an individual dry vent, a wet vent, a common vent, a circuit or loop vent, an island vent or a combination waste and vent system. g)         Mechanical Vents.  Mechanical devices shall not be installed in lieu of vent piping. h)         Trap Seal Loss.  Trap seal that is subject to loss by evaporation shall be prevented.  (See Section 890.410(f).)