Can I exhaust a Mechanical Unit out the Lot Line wall of a building?

Q: Can I exhaust a Mechanical Unit out the Lot Line wall of a building?

A: No. Per the below Code Section, from BC RS 13-1, "Installation of Air Conditioning and Ventilating Systems", an exhaust duct to the exterior shall terminate at or above the Roof of the building, or in an exterior wall adjoining a street, yard, or court.

However, where the Lot Line adjoins an adjacent lot that shall not be developed (eg: a Landmark Church or similar), it may be worthwhile to seek a Reconsideration, since there is little or no chance that the adjacent lot will be developed further.

Refer to excerpt from RS 13-1 below for full details:

2-3.4.3 To minimize the hazard from fires in other structures, an exhaust duct to the outdoor air shall terminate at or above the roof of the building or in an exterior wall adjoining a street, yard or court.

When terminated in an exterior wall, the exhaust duct shall be at least 10 feet above the sidewalk or ground and shall terminate at least 10 feet from any window in another building or from any window in a residential portion of the same building, or from any fire escape, exterior stair, or balcony.

No exhaust duct or outdoor air intake shall be located where conflict with the operation of an existing intake or other ventilating opening. Exhaust openings shall be provided with vanes or louvers constructed so as to direct the air away from windows, other openings, and pedestrians.

An outdoor air intake opening with gross area of more than 144 square inches shall be provided with fire dampers when such opening is located as follows:
(a) Less than 30 feet above grade.
(b) Less than 30 feet in any direction from any opening in another building.
(c) Less than 15 feet from a lot line.
(d) Less than 50 feet above and less than 50 feet in any direction from a roof of combustible material or a building in which the exterior walls are constructed wholly or partly of wood.

When required by the commissioner, approved heat actuated devices shall be installed at intake openings to shut down fans in case of an exterior fire.