Roof Drain Leader Sizing

Roof drainage 2016 05 11 plumbing roof drains table of contents storm drainage system research gutters and downspouts hydromax siphonic drainage work.

Roof drain leader sizing.

Enter table 1108 1 until you find a diameter pipe that will carry 2 344 sq ft. If the result is a fraction less use the next higher number. Roof area is 300 x 500 ft. Determine the size of leader to be used.

By doni anto may 12 2020. 2 500 4 x 3 75 2 344 sq ft. Sizing a roof water drain. 1 2 inch per foot.

Divide the total roof area by the area that one leader will handle. This reveals that the minimum size for the leader pipe is 5. Roof drainage 2016 05 11 plumbing mechanical. Each 4 drain size in a 6 hourly rainfall area will accommodate drainage of 3 070 sq.

The re quirement for gallons per minute gpm flow through the. The vertical flow rates shown in tables 1106 2 1106 3 are full. 2 3 4 5 6 and 8 in. 2 3 4 and 6 in.

1 8 inch per foot. Total roof area 500 by 200. Select a reference of a roof drain size with hourly rainfall together with the roof area square footage you have estimated and then determine from the chart below how many roof drains you require. Section 101 5 of the ipc tells us not to reduce the pipe size in the direction of flow.

But this isn t the whole story. 2 3 4 5 6 and 8 in. Presently the amse a112 6 4 roof drain standard is being revised by the asme roof drain committee. The above result is the number of roof drains required for the building.

Square feet that can be drained by one roof leader at the local maximum rainfall rate. Roof drain leader sizing. 1 16 inch per foot. Slope of horizontal drain.

Each vertical drain must carry 2 500 sq ft of roof area at 3 75 inches per hour of rainfall. 1 4 inch per foot. 4 leader size is selected. 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.

A minimum 4 inch vertical drain is required. Calculate total roof area. 2 3 4 5 6 and 8 in. Determine leader or pipe size.

Size of leader in inches vertical leader sizing capacity in gpm 2 30 3 92 4 192 5 360 6 563 8 1 208 note. 300 x 500 150 000 sq. To convert to an area for a 4 inch per hour rainfall to enter table 1108 1 do this. Following are the standard sizes for some of the top manufacturers.

Above sizing data is offered as a guide only. 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.