Calculate total roof area.
Roof drainage design guide.
2 3 4 5 6.
Type of roof construction 2.
Properly designed roof drain must have the following features.
Calculate the total roof area by multiplying its length by width.
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.
In either case the discharge shall be located so that it is readily visible by building occupants.
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.
2 3 4 5 6 and 8 in.
Ipc provides four steps to size the roof drains on a building.
When selecting a roof drain note.
First and foremost be sure to comply with all local plumbing codes.
Maximum pipe flow.
Structural design of the roof and roof load.
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.
Determine 100 year 1 hour rainfall rate used for location of building.
Size horizontal storm drainage piping.
From there consider the following.
Desired rate of drainage 6.
Inspect the roof surface and roof drains on a regular schedule to find and clear away any debris clogging the drains.
Determine leader or pipe size.
In the design and detailing of a roof drainage system consideration must be given to a range of factors such as.
Step by step instructions step 1.
Safety load requirement 8.
Volume of expected rainfall.
Roof load requirement 7.
Roofs inevitably serve as temporary rainwater reservoirs.
Inspect the current roof drain s and the drain line through the building for leaks and assure that the materials are.
Secondary or emergency roof drainage is required wherever the buildup of water is detrimental to the roof structure.
Location of drains 5.
The location and degree to which.
Slope of the roof.
To select the proper roof drain the following information must be known.
Select number of roof drains and calculate the roof area sloped to each drain.
The greater the slope the less water build up and thus roof load.
Size vertical storm drainage piping.
