Loading...
Whenever a combined sewer system is employed, the required size of the combined house sewer shall be determined by adding the total drained area in square feet in Table 18-29-1106.2 and equivalent area for the number of fixture units in accordance with Table 18-29-1108.1.
No. of Fixture Units | Equivalent Area (sq. ft.) | No. of Fixture Units | Equivalent Area (sq. ft.)* |
No. of Fixture Units | Equivalent Area (sq. ft.) | No. of Fixture Units | Equivalent Area (sq. ft.)* |
1 | 165 | 31 | 2,820 |
2 | 325 | 32 | 2,870 |
3 | 475 | 34 | 2,955 |
5 | 750 | 38 | 3,125 |
6 | 875 | 40 | 3,200 |
7 | 1,000 | 42 | 3,270 |
8 | 1,115 | 44 | 3,340 |
9 | 1,225 | 46 | 3,400 |
10 | 1,330 | 48 | 3,465 |
11 | 1,435 | 50 | 3,350 |
12 | 1,530 | 55 | 3,530 |
13 | 1,620 | 60 | 3,790 |
14 | 1,710 | 65 | 3,900 |
15 | 1,800 | 70 | 4,000 |
16 | 1,880 | 75 | 4,090 |
17 | 1,960 | 80 | 4,175 |
18 | 2,040 | 85 | 4,250 |
19 | 2,110 | 90 | 4,320 |
20 | 2,180 | 95 | 4,390 |
21 | 2,250 | 100 | 4,450 |
22 | 2,310 | 105 | 4,500 |
23 | 2,360 | 110 | 4,550 |
24 | 2,440 | 115 | 4,600 |
25 | 2,500 | 120 | 4,645 |
26 | 2,550 | 125 | 4,690 |
27 | 2,600 | 130 | 4,725 |
28 | 2,660 | 140 | 4,800 |
29 | 2,710 | 145 | 4,830 |
30 | 2,770 | 150 | 4,850 |
* For more than 150 fixture units, the equivalent area shall be determined by adding 7.2 square feet for each fixture unit over 150 to 4,850 square feet.
Where there is a continuous or semi-continuous discharge into the building storm drain or building storm sewer, such as from a pump, ejector, air conditioning plant or similar device, each gallon per minute (L/m) of such discharge shall be computed as being equivalent to 24 square feet (2.25 m
2
) of roof area. (See Table 18-29-1108.1)
The roof of a structure shall be designed for the storage of water where the storm drainage system is engineered for controlled flow. The controlled flow roof drain system shall be an engineered system in accordance with this section and the design, submittal, approval, inspection and testing requirements of Section 18-29-1105.4. In lieu of the conventional downspout requirements of Section 18-29-1106, controlled flow roof drainage may be used. The water of a 25 year frequency shall not be stored on the roof for more than 24 hours. The water depth on flat roofs shall not exceed 3 inches (75 mm) during the above storm and 3 inches (75 mm) average depth on sloped roofs not exceeding 6 inches (32 mm) rise or depth of slope.
Loading...