Section 1502. Roof Drainage

1502.1 to 1502.4 {As in IBC}

1502.5 General discharge requirements.

Gutters, downspouts, and leaders must be provided on all buildings to properly collect, conduct, and discharge the water from their roofs into a storm drain or into the driveway of an alley, street, or other public way. No water from any building may be discharged so as to run or flow over any sidewalk, footway, or any adjoining property, except from window sills, copings, or cornices that project no more than 1 foot (305 mm).

1502.5.1 Exceptions.

This § 1502.5 does not apply to:

1. roofs, cornices, copings, or other similar projections that are less than 5 feet (1.52 m), measured horizontally in the line of flow, as long as the water from them is not discharged on any sidewalk, footway, or adjoining property, or

2. awnings or marquees that discharge off the outer edge.

1502.5.2 Methods.

Drainage must be conveyed in 1 of the following methods.

1502.5.2.1 Method 1.

Drainage may be discharged by piping to a storm drain, to the street or alley, or to an approved water course. The installation of piping, connections to storm drains, etc., must be made in accordance with the plumbing regulations of Chapter 29 {"Plumbing Systems"} of this Code. Any continuous discharge of drainage water into the public right-of-way of such a volume and frequency as to cause ponding or icing is prohibited and must be conveyed to the nearest public storm water drain or inlet through underground piping.

1502.5.2.2 Method 2.

Drainage may be discharged not less than 10 feet (3.05 m) from the building, from other buildings, or from any adjacent property line, as long as the discharge is in such a manner as not to allow drainage to cross adjacent property lines or sidewalks.

1502.5.3 Individual downspouts.

Gutters of buildings on adjoining properties may not be connected with common downspouts or leaders, but each building must have individual downspouts or leaders on its own property. If a building is more than 4 stories or 50 feet (15.24 m) high, its leader and downspouts must be inside the building's exterior walls.

1502.5.4 Relief scuppers.

Roofs with interior roof drains and enclosed by parapet walls that will impound water must be provided with relief scuppers placed in the parapet wall not more than 6 inches (152 mm) above the roof level. The openings of these relief scuppers must be at least 6 inches (152 mm) in diameter. Each 6-inch (152-mm) diameter relief scupper opening may only serve a roof area of not more than 1,000 square feet (92.9 square meters).

1502.5.4.1 Internal relief drains.

Internal relief drains may be used instead of relief scuppers. Internal relief drains must be independent of the required roof drains.