Roof Drainage Design Standard

The manual is intended to be used in conjunction with bs en 12056 3 and contains separate chapters dealing with the following topics.

Roof drainage design standard.

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. Manual for the design of roof drainage systems a guide to the use of european standard bs en 12056 3 2000 r w p may report sr 620 march 2003 address and registered office. Hr wallingford ltd howbery park wallingford oxon ox10 8ba. The roof design standards focus on high quality and long term performance.

To design a sloped or flat roof drainage system we need to know several things. This manual was produced based on experience and expertise in 40 year roof performance. Roof drainage layout and calculations. 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.

In the design and detailing of a roof drainage system consideration must be given to a range of factors such as. This modular system is one of six variations installed on the roof and covers 800 square feet con sisting of two foot by two foot trays with six inches of mineral soil and over 1 500 sedum plugs. For most dwellings you ll find that gutters range in size from approximately 100mm diameter to 150mm diameter assuming gutters with a half round section profile and downpipes range from approximately 60mm diameter to 90mm diameter assuming circular downpipes. Drainage area a with sub areas 1 thru 7 delineated in the absence of a minimum design factor based on the structural design of the pavement the res ervoir depth should be a minimum of 6 inches above the underdrain or choker layer.

Typical problems and design. An extensive green roof system installed atop the nyc department of parks and recreation s dpr five borough building on randall s island. Rainfall data effective catchment area design flow loads capacity of freely discharging gutters. Hence this is by far the most common roof drainage situation.

Typically a low slope roof is designed with one primary roof drain and one secondary roof drain or overflow scupper drainage outlet at the perimeter of the building per structural bay. Quantity and placement of downpipes. Roof drainage systems should be designed and detailed by a suitably qualified trade or professional in accordance with the bca and the australian standards. And the provision of appropriate overflow devices.

Minnesota state goal for roofing performance. The maximum rainfall rate anticipated in the area where the building is located the flow in liters per minute per square meter for some x number of minutes.