How To Know The Number Of Roof R Drains

Take the roof s total square footage and divide by the total square footage handled by one drain.

How to know the number of roof r drains.

Gutters come in many sizes. The 6 in 12 pitch factor 1 1 multiplied by 1 000 yields an effective area of 1 100 square feet. 2 total area of roof. The result is the number of drains needed.

2 estimate the roof drain outlet. How to calculate the quantity of drains required. Select number of roof drains and calculate the roof area sloped to each drain. Each leader must be large enough to handle the volume of water to be drained the greater the leader capacity the fewer roof drains are needed.

The flow rate used for sizing the storm drainage piping shall be based on the maximum anticipated ponding at the roof drain. 1 rate of precipitation. Is there a rule of thumb for number of roof drains needed on flat roofs. 3 size of leader required.

Multiplying that number by the local maximum rainfall intensity 6 8 inches per hour yields an adjusted square footage of 7 480 square feet. The number of roof drains required for the building. Using tools from the international plumbing code ipc it s not that hard. If the result is a fraction less use the next higher number.

When determining the number roof drains required recognize that the smaller the roof drain outlet diameter the more drains you will need. 6 24 2014 david howard aia said. A high slope moves water more quickly and if gutters have trouble dealing with a lot of water in a short period of time an extra downspout can alleviate that issue. Total roof area 500 by 200 100 000 sq.

Ipc provides four steps to size the roof drains on a building. A large roof is going to move a lot of water which means the downspout locations may need to be adjust to compensate. Conversely the larger the drain outlet diameter the fewer you will need. What is the general area of a flat 1 4 1 0 slope single ply roof for each roof drain ratio for the number of roof drains roof area.

The four things you will need to know are. Determine 100 year 1 hour rainfall rate used for location of building. 1 calculate the roof area to be drained. And 4 area handled by each drain.

50 000 4 400 11 36. After studying building plan and physical. Or 12 drains required. Zurn makes it easy to size roof drains.

The published roof drain flow rate based on the head of water above the roof drain shall be used to size the storm drainage system in accordance with section 1106. Size horizontal storm drainage piping. Next the roof area is divided by the area for each leader to determine the number of drains required.