How Many Downpipes For Roof Area Australia

Multiplying that number by the local maximum rainfall intensity 6 8 inches per hour yields an adjusted square footage of 7 480 square feet.

How many downpipes for roof area australia.

A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour. The most common roofing materials used in the united states include shingles membrane roofing and ceramic tile all of which have different life spans. Doubling the number of downspouts halves the required capacity for each. Whether or not your area gets a lot of rainfall it s essential to have downpipes that are connected correctly in order for them to work efficiently.

The gutters downpipes and overflow gdo calculator assists in developing a better understanding of the ncc volume two part 3 5 3 gutters and downpipes acceptable construction practice acp provisions. The 6 in 12 pitch factor 1 1 multiplied by 1 000 yields an effective area of 1 100 square feet. The answers for downpipe size are in mm. Size downspouts to fit the gutter.

Select 100 x 50 rectangular downpipe. Divide the main roof into catchments of this size and any left over area can be entered again to find a down pipe size for this smaller area. A house in chicago has a roof whose actual drainage area is 1 000 square feet. Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed.

Calculators for designing eaves gutters box gutters downpipes pipes and open channels etc to australian standards. This is because larger roofs require bigger volumes of water to be diverted away from them during periods of rainfall. Design of eaves gutters box gutters downpipes to the australian national plumbing code as nzs 3500 3. Downpipes generally carry water from a roof to either a drain or to ground level and are an essential part of any building s drainage system.

How many downpipes do you need. Shingle roofs typically have a life span of 15 30 years. The number of downpipes you need will depend on the size of your roof and your chosen style of guttering. To use the gdo calculator enter information about the location roof design and types of overflow measures.

To calculate the minimum number of downpipes divide the roof catchment area by the allowable maximum catchment per downpipe. Determine minimum number of downpipes. Downpipes have a limit of 50 sqm per downpipe the area of your roof space is 280 58 sqm the roof catchment space is 331 0844 sqm o please see my calculations below o 331 0844 50 sqm 6 6 o based on these calculations you will need 6 6 downpipes to manage the water flow. The program will calculate the most suitable circular and rectangular downpipe sizes.

From figure 3 5 a in as nzs 3500 3 the maximum catchment per downpipe is 47m 2.