The gutter outlet capacity should suit the downspout capacity.
Gutter downspout capacity.
The downspout and gutter sizing calculator is located on the tools cad and apps page of the smacna website.
15 m is a practical maximum gutter length to be served by a downspout.
The risk of rain gutter overflow from insufficient drainage capacity.
Roof area the locale s rainfall intensity and gutter capacity determine how many square inches of downspout are needed.
A square inch of downspout can drain 1 200 square feet of roof during a rain with an intensity of one inch per hour.
Adding a 2 by 3 rectangular downspout for instance boosts your gutter s capacity by 600 square feet of drainage area.
The downspout size must suit the bottom width of the gutter.
Rectangular 2 by 3 inches 600 square feet 3 by 4 inches 1 200.
A scupper serving a designated roof area ï after the number and location of downspouts have been determined the areas to be drained by each downspout should be figured.
These are safe numbers meaning designed to work under the strongest rainfall not the average for.
Adding a 2 by 3 rectangular downspout for instance boosts your gutter s capacity by 600 square feet of drainage area.
As with gutters a downspout s capacity must match or exceed the expected runoff.
Water capacity values of a gutter downspout system is calculated using the height head of water a gutter can hold the outlet orifice size of the downspout and the quantity of downspouts used.
How to make sure your gutter is large enough and you have enough downspouts.
Van mark brakes ladder max stabilizer outlet punches gutter mate nail hawg end cap crimpers soldering irons accessories downspout crimpers snips hand seamers hand notchers drill bits chuck drivers gloves folding tools gutter nail driver rivet gun 3 8 awl large grip 12 combination.
Doubling the number of downspouts halves the required capacity for each.
Design of roof drainage systems roof drainage the roof is one of the most essential parts of a building as it protects occupants contents and interior of the structure from the elements.
Use the chart below to figure out how many extra downspouts you need.
To limit the effects of thermal expansion in gutters 50 ft.
Use the chart below to figure out how many extra downspouts you need.
Now architects engineers designers and contractors can easily and accurately size downspouts and gutters according to the specifications in smacna s architectural sheet metal manual 7th edition 2012.
Gutter and downspout water capacity.
3 by 4 inches 1 200 square.
Use the helpful charts below and you ll be a near expert in no time.
2 by 3 inches 600 square feet.
The capacity of a sloped rectangular gutter may be approximated by using a gutter cross section area not less than that of a semicircular gutter and.
Size downspouts to fit the gutter.
It is possible to use a mix of gutter sizes a mix of downspout sizes and quantities to accommodate the theoretical gallons per minute draining.
