1103.4 Side Walls Draining onto a Roof.

Where vertical walls project above a roof to permit storm water to drain into the roof area below, the adjacent roof area shall be permitted to be computed from Table 1103.1 as follows:

2019 CALIFORNIA PLUMBING CODE 213

STORM DRAINAGE any other purpose or distributed to any other persons or parti es.

(1) For one wall – add 50 percent of the wall area to the roof

area figures.

(1) For one wall – add 50 percent of the wall area to the roof

area figures. (2) For two adjacent walls of equal height – add 35 percent

of the total wall areas.

(6) The height of stones or other granular material above the

waterproofed surface shall not be considered in water

(2) For two adjacent walls of equal height – add 35 percent

of the total wall areas. (3) For two adjacent walls of unequal height – add 35 per cent of the total common height and add 50 percent of

(3) For two adjacent walls of unequal height – add 35 per cent of the total common height and add 50 percent of the remaining height of the highest wall. (4) Two opposite walls of same height – add no additional

area.

(6) The height of stones or other granular material above the

waterproofed surface shall not be considered in water depth measurement, and the roof surface in the vicinity of the drain shall not be recessed to create a reservoir. (7) Roof design, where controlled-flow roof drainage is

used, shall be such that the design roof live load is not

(4) Two opposite walls of same height – add no additional

area. (5) Two opposite walls of differing heights – add 50 percent

of the wall area above the top of the lower wall.

(5) Two opposite walls of differing heights – add 50 percent

of the wall area above the top of the lower wall. (6) Walls on three sides – add 50 percent of the area of the

inner wall below the top of the lowest wall, plus an

(7) Roof design, where controlled-flow roof drainage is

used, shall be such that the design roof live load is not less than 30 lb/ft ² (146 kg/m ² ) to provide a safety factor exceeding the 15 lb/ft ² (73 kg/m ² ) represented by the depth of water stored on the roof in accordance with Table 1105.1(1). (8) Scuppers shall be provided in parapet walls. The distance

of scupper bottoms above the roof level at the drains shall

(6) Walls on three sides – add 50 percent of the area of the

inner wall below the top of the lowest wall, plus an allowance for the area of the wall above the top of the lowest wall, in accordance with Section 1103.4(3) and Section 1103.4(5) above. (7) Walls on four sides – no allowance for wall areas below

the top of the lowest wall – add for areas above the top

(8) Scuppers shall be provided in parapet walls. The distance

of scupper bottoms above the roof level at the drains shall not exceed the maximum distances specified in Table 1105.1(2). (9) Scupper openings shall be not less than 4 inches (102

mm) high and have a width equal to the circumference of

Walls on four sides – no allowance for wall areas below

the top of the lowest wall – add for areas above the top of the lowest wall in accordance with Section 1103.4(1), Section 1103.4(3), Section 1103.4(5), and Section 1103.4(6) above.

(9) Scupper openings shall be not less than 4 inches (102

mm) high and have a width equal to the circumference of the roof drain required for the area served, sized in accordance with Table 1103.1. (10)Flashings shall extend above the top of the scuppers. (11) At a wall or parapet, 45 degree (0.79 rad) cants shall be

installed.

(11) At a wall or parapet, 45 degree (0.79 rad) cants shall be

installed. (12)Separate storm and sanitary drainage systems shall be

provided within the building.

(12)Separate storm and sanitary drainage systems shall be

provided within the building. (13)Calculations for the roof drainage system shall be sub mitted along with the plans to the Authority Having Juris