What minimum height must a vent pipe extend above the roofline?

The correct minimum height for a vent pipe to extend above the roofline is 1500 mm (5 feet). This specification is intended to ensure adequate venting performance and to prevent problems associated with wind and snow from obstructing the vent, which could lead to dangerous sewer gases accumulating within the building. By setting this height requirement, the National Plumbing Code of Canada helps maintain safe indoor air quality, facilitates proper drainage system function, and minimizes the potential for backpressure within the plumbing system.

Maintaining this height not only safeguards against external environmental factors but also aligns with best practices for plumbing ventilation, ensuring that the air could flow freely without interference.