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EAVES GUTTER AND DOWN PIPE DESIGN TO AS/NZS 3500.3: 2015
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Horizontal catchment area
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Ah
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=
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sq.m
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Roof slope
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S
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=
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degrees
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Intensity
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I
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=
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mm/hr
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Is Gutter slope steeper than 1:500 ?
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Selected Number of Down pipes
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n
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=
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From AS 3500 Table 3.4.5.2, Catchment Area Multiplier
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f
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=
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Roof Area allowing for slope
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Ac
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=
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Ah*f
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=
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sq.m
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Catchment Area per DP
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A
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=
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Ac/n
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sq.m
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=
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sq.m
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Flow/DP
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q
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=
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I*A/3600
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litres/sec
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=
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litres/sec
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from AS/NZS 3500 fig 3.5.2(C), Gutter Area |
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=
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sq.mm |
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Gutter Area rounded to nearest 100sq.mm
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=
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sq.mm
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From AS/NZS 3500 Table 3.5.2,, Down Pipe size |
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=
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mm
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(Interpolating between the standard sizes of the table. Info Only)
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=
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mm
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Cross sectional area (Info Only)
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=
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sq.mm
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Down Pipe size selected
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=
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mm
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cross sectional area
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=
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sq.mm
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Summary
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This catchment requires :- number of DP's
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=
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Downpipe size
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=
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mm
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minimum eaves gutter cross sectional Area
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=
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sq.mm |
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(note assuming the catchment area of each DP is roughly similar)
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