How Many Downpipes For Roof Area

Roof area m gutter flow litres sec roof area m downpipe at centre half round 76mm 0 7 34 0 8 38 112mm 1 8 86 2 6 125 squareflo 3 2 154 3 8 182 125 68mm downpipe 3 8 182 4 6 221 82mm downpipe 4 0 191 4 9 235 regency 4 2 202 4 7 226 highflo 5 4 258 6 0 289 stormflo 110mm 11 1 534 12 4 598 160mm 12 5 601 14 0 673 downpipe at end half.

How many downpipes for roof area.

There is no limit to downpipe size or eaves gutter size. The 6 in 12 pitch factor 1 1 multiplied by 1 000 yields an effective area of 1 100 square feet. Using the aggregate area of these simple shapes can yield a more accurate roof area to be used with the roofing material calculator. Frequency and positioning of outlets downpipes calculate the number of outlets per run.

Take the roof s total square footage and divide by the total square footage handled by one drain. The result is the number of drains needed. Roof length x half roof width x roof height 2 roof area. From figure 3 5 a in as nzs 3500 3 the maximum catchment per downpipe is 47m 2.

Shingle roofs typically have a life span of 15 30 years. Select 100 x 50 rectangular downpipe. A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour. To calculate the minimum number of downpipes divide the roof catchment area by the allowable maximum catchment per downpipe.

It is the roof area the pitch of the roof and the number of drops downpipes coming down from outlets in the guttering around the building determine the flow we will need to know these to calculate the flow capacity for you. Or 12 drains required. The most common roofing materials used in the united states include shingles membrane roofing and ceramic tile all of which have different life spans. 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. Doubling the number of downspouts halves the required capacity for each. 50 000 4 400 11 36. Choosing the right style of guttering downpipes.

The code limit is 150mm for dp s and 26 800 sq mm for flat eaves gutters the program will calculate the size and number of downpipes downspouts leaders required and the eaves gutter sizes for any roof. Feb 21 2011 prior to the water reaching the detention tank there are 5 x 90mm downpipes which join into 2 x 100mm pipes as soon as they reach the ground and then feed into the tank. Multiplying that number by the local maximum rainfall intensity 6 8 inches per hour yields an adjusted square footage of 7 480 square feet. Determine minimum number of downpipes.