The Ontario Building Code | Unions and Slip Joints

7.3.3.4. Unions and Slip Joints

(1) Running thread and packing nut connections and unions with a gasket seal shall not be used downstream of a trap weir in a drainage system or in a venting ="http://thehandyforce.com/interior/bathroom-renovations/" title ="Toronto Bathroom renovation inspiration">venting system.

(2) A slip joint shall not be used,

(a) in a venting ="http://thehandyforce.com/interior/bathroom-renovations/" title ="Toronto Bathroom renovation inspiration">venting system, or

(b) in a drainage system, except to connect a fixture trap to a fixture drain in anaccessible location.