Pto Roof Drain Spacing

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

Pto roof drain spacing.

A minimum 4 inch vertical drain is required. The drainage coefficient is the design capacity of the drainage system and is typically expressed as a depth of water removed in 24 hours inches day. Mechanically fasten all tapers using two fasteners per board. Each vertical drain must carry 2 500 sq ft of roof area at 3 75 inches per hour of rainfall.

The roof drain or gutter or drain piping or downspout leader size diameter other size constraints e g. Designers specify compliance with bs en 12056 3 2000 that includes a calculation for the allowable capacity of the rainwater pipes. An additional roof drain should be added for each 10 000 square foot area. The full flow capacity of a drain is not realized until the water reaches approximately 2 5 above the inlet in a four inch drain and 3 5 in a six inch drain.

To convert to an area for a 4 inch per hour rainfall to enter table 1108 1 do this. 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. Typical range 0 25 to 0 5 inches day. The required parameters for the drain spacing calculator with typical values for the upper midwest and a reference diagram are as follows.

Intensive layered green roof intensive green roofs have a deeper soil depth therefore the roof drain enclosure height is typically 12 or more. If insulation thickness exceeds 1 taper 18 from the drain bowl. Enter table 1108 1 until you find a diameter pipe that will carry 2 344 sq ft. 2 500 4 x 3 75 2 344 sq ft.

Once the drainage system is determined the designer must ensure positive drainage by correctly positioning the roof drains. According to the chart for 1 8 slope per 12 of pipe for 5 000 square feet of roof area with a 6 per hour of rainfall the required pipe size is 8. The sizing of roof drains must be large enough to quickly carry away all water entering the roof drains. A good rule to follow is to provide two roof drains for a total roof area less than 10 000 square feet.

Z110 green roof drain shown with 18 height for intensive green roofing applications. The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process. 50 000 4 400 11 36. For example in the u k.

The result is the number of drains needed. The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures. Or 12 drains required.