Interpretation No. 5069 – Vent Terminal Location and Clearance Requirements

Manual Reference Section: 5
Applicable Code: BC Plumbing Code (1998), Part 7, Section 7.5
Status: Approved (with revision 5069-2)

Background

Interpretation No. 5069 was issued by the Plumbing Officials’ Association of British Columbia to resolve questions concerning the proper placement of vent terminals where they exit through or adjacent to building roofs. The original ruling was subsequently revised as Interpretation 5069-2 to address an additional scenario involving vent terminals near operable windows and air intake openings.

Subject Matter

The enquiry posed to the Association concerned the minimum clearance distances required between vent pipe terminals and various building features, including roof surfaces, adjacent walls, property lines, and mechanical air intake openings. A secondary question, addressed in the revision, asked whether the required clearances could be reduced when physical constraints on the roof made full compliance impractical.

Ruling

The Association confirmed that all vent terminals must extend a minimum of 150 mm above the roof surface at the point of penetration, as stipulated in Subsection 7.5.10 of the 1998 BC Plumbing Code. In regions subject to heavy snowfall, the terminal was required to extend above the anticipated snow accumulation line, with a minimum height of 600 mm recommended for most British Columbia climate zones outside the lower coastal areas.

Vent terminals were required to maintain a horizontal clearance of at least 900 mm from any openable window, door, or mechanical air intake, measured from the centre of the vent pipe to the nearest edge of the opening. Where the vent terminal was positioned above the level of the opening, the clearance could be measured on the horizontal plane.

The revision (5069-2) addressed situations where building geometry prevented full compliance with the horizontal clearance requirement. The Association ruled that no reduction in the prescribed clearances was permitted. Where site conditions made standard vent terminal placement unachievable, the vent pipe was to be extended vertically to a height at least 600 mm above the nearest opening, thereby ensuring that sewer gases would disperse before reaching the air intake or window elevation.

All vent terminals were required to be fitted with a corrosion-resistant screen or cap designed to prevent the entry of birds, vermin, or debris without restricting airflow through the vent pipe.

Scope of Application

This interpretation applied to all building types and was relevant to both new construction and reroofing projects where existing vent terminal heights might be affected by changes in roof elevation or the addition of rooftop mechanical equipment.