A vent is proposed to terminate through a sidewall at a point 4 feet below an openable bedroom window and 5 feet to the side of it. Take as given the code rule that a vent terminal must be at least 3 feet above any opening within 10 feet of it. Does the proposed location comply?
- AYes, because the terminal is more than 3 feet away from the window measured in a straight line
The 3 foot dimension in the rule is a vertical measurement above an opening, not a straight-line separation. Applying it as a radius misreads the requirement.
- BYes, because the rule applies only to terminals located above an opening, not below one
Nothing in the rule limits it to terminals above openings. A terminal below an opening is the case the vertical requirement exists to prevent.
- No, because the terminal is within 10 feet of the opening and is below it rather than 3 feet above it
- DNo, because a sidewall terminal may never be located on the same wall as an openable window
Sidewall terminals on a wall with windows are routine. They simply have to satisfy the distance or the height relationship to each opening.
Why C is correct
Sewer gas is warm and rises, so a terminal below an opening is the worst case rather than a neutral one. Inside the 10 foot radius the only compliant arrangement puts the terminal well above the opening, and this one is 4 feet under it.
What this question is testing
Whether the candidate can apply a two-part clearance rule to a specific geometry and recognize that a terminal below an opening does not satisfy an above-the-opening requirement.
On the job
Sidewall vent terminals get located by whatever is convenient on the elevation, and second-floor windows above them are easy to overlook from the ground. Walk the exterior with the elevations in hand and look up. This same relationship applies to doors, air intakes, and the soffit vents on a roof overhang, all of which count as openings drawing air into the building.
Memory technique
Ten feet away or three feet above. Underneath is always wrong.
Exam tip
Read clearance rules as either-or. Far enough away horizontally, or high enough above. Below never counts.
Where to look it up
IPC Chapter 9, the vent terminal provisions covering location relative to openings, read with the sidewall terminal requirements. The UPC uses its own dimensions for the same relationship, so verify in your adopted code.