Developing the design criteria for a roof drainage plan that will perform with the roofing system to drain the roof is critical priorto the bid process and roof system installation.
Roof drainage design guide.
Determine 100 year 1 hour rainfall rate used for location of building.
Volume of expected rainfall.
Roof load requirement 7.
The sizing of the roof drainage system must consider all components.
Rainfall intensity roof catchment area gutter size capacity gutter fall gutter outlets sumps rain heads nozzles downpipe size quantity and placement overflow consideration material.
Structural design of the roof and roof load.
Maximum pipe flow.
The rain storm the flow of rainwater on the roof surface the ability of the roof drain to move the water from the roof to the piping the vertical piping the horizontal piping and the connection to the point of discharge.
Secondary or emergency roof drainage is required wherever the buildup of water is detrimental to the roof structure.
Roofs inevitably serve as temporary rainwater reservoirs.
Select number of roof drains and calculate the roof area sloped to each drain.
Ipc provides four steps to size the roof drains on a building.
Size vertical storm drainage piping.
In either case the discharge shall be located so that it is readily visible by building occupants.
From there consider the following.
Safety load requirement 8.
Step by step instructions step 1.
First and foremost be sure to comply with all local plumbing codes.
Pleasing dome shape with a low profile and adequate free drainage area corrosion resisting dome material effective debris protection overflow drainage to allow drainage during debris build up gravel stop positive flashing clamp seepage control channels.
Secondary drainage shall be provided through the use of sidewall scuppers or internal roof drains.
The greater the slope the less water build up and thus roof load.
Size horizontal storm drainage piping.
Calculate the total roof area by multiplying its length by width.
Calculate total roof area.
When selecting a roof drain note.
2 3 4 5 6 and 8 in.
Location of drains 5.
Design assistance services are offered as a courtesy to the roofing design professional and contractors to ensure the project s success.
Slope of the roof.
Properly designed roof drain must have the following features.
Determine leader or pipe size.
2 3 4 5 6.
Inspect the roof surface and roof drains on a regular schedule to find and clear away any debris clogging the drains.
The location and degree to which.
Inspect the current roof drain s and the drain line through the building for leaks and assure that the materials are.
To select the proper roof drain the following information must be known.
