Roof Leader Sizing

Table 1106 3 vertical leader sizing for si.

Roof leader sizing.

The flow rate through vertical leaders shall not exceed that specified in table 1106 3. Use12 ichwdex5 inch high scuppers at four locations. 1 rate of precipitation. Take the roof s total square footage and divide by the total square footage handled by one drain.

Smacna s new downspout and gutter sizing calculator enables the user to manually enter the design area of the roof or use the design area wizard for the calculation. This corresponds to a minimum top width of 6 inches. When sizing roof drains the limiting factor for the amount of water each drain will carry away is the size of leader therefore increasing. The result is the number of drains needed.

2 500 4 x 7 2 9 375 sq ft 4 500 sq ft. System sizing data rainfall when expressed in g p m. The availability of 7 inch top width k style gutter has been poor in the past. 3 size of leader required.

The use of 4 x 5 downspout outlets starts at a depth of gutter of 4 5 inches. Zurn makes it easy to size roof drains. 2 total area of roof. Or 12 drains required.

The four things you will need to know are. The next step is to determine each roof area that will be served by a separate leader drain pipe scupper or downspout. Section 101 5 of the ipc tells us not to reduce the pipe size in the direction of flow. 1 inch 25 4 mm 1 gallon per minute 3 785 l m.

To size the vertical roof drain for the same parameters 5 000 square feet of room area and 6 per hour of rain consult table 1106 2 figure 3. Sizing a roof water drain. The first step in sizing a roof drain is to calculate the surface area of the roof that the drains will be covering as well as the average hourly rainfall rate at the building location. But this isn t the whole story.

Vertical leaders shall be sized based on the flow rate from horizontal gutters or the maximum flow rate through roof drains. This wizard makes it easy to calculate the roof design area by providing various shape calculations and the calculation for vertical walls area per international plumbing code ipc. Can be applied to the table in figure 8 to determine the sizes of the various components of the conventional roof drainage system including roof drains vertical leaders and horizontal drainage piping. Enter table a101 2 to find a length and head that will carry 4 500 sq ft or more.

From table a101 2 a 12 inch wide weir with a inch head carries6 460 sq ft. 50 000 4 400 11 36. Using figure 8 the 312 g p m. This reveals that the minimum size for the leader pipe is 5.