Box Guter No. 111
Job no 007
Design: BTW
1st Jan 2000
BOX GUTTER AND RAIN WATER HEAD DESIGN TO AS/NZS 3500
.3:
2015
Industrial Building for Mr Blogs
Somewhere Lane, Somewhere Else.
Diagramaic shape of Given Data (Not to scale)
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Ah
Av
Ac
LHS
RHS
=
=
=
=
=
Area Horiz
Area Vert'l
Area Cment
Left hand
Right hand
sq.m.
sq.m.
sq.m.
side
side
Design Storm Intensity (ARI 100)
I
=
330
mm/hr
Catchment Areas as shown in the diagram.
Calculate roof rise areas.
Roof Slope LHS = 2 deg Therefore
Av1
=
Ah1*tan(Slope)
sqm
Av1
=
111*tan(2)
=
3.9
sqm
Roof Slope RHS = 5 deg Therefore
Av3
=
Ah2*tan(Slope)
sqm
Av3
=
22*tan(5)
=
1.9
sqm
Calculate catchment area for each wind direction
Ac = Ah + 1/2(Av facing wind - Av causing rain shadow)
wind from LHS
Ac(LHS)
=
111+22+0.5*(1.9+22-3.9-11)
=
137.5
sq.m
wind from RHS
Ac(RHS)
=
111+22+0.5*(3.9+11-1.9-22)
=
128.5
sq.m
wind from front
Ac(front)
=
111+22+0.5*(20-0)
=
143
sq.m
Worst wind direction is from the front
Ac
=
143
sqm.
Design Flow
Q
=
I*Ac/3600
Litres/sec
=
330*143/3600
Litres/sec
=
13.1
Litres/sec
Box Gutter Depth
From Fig I1 (Interpolating where necessary)
Using :- Gutter Slope
1
in
200
and Gutter Width
W
=
300
mm
from fig I1 Minimum Gutter Depth
d
=
155
mm
Rain Water Head Calculations
Selected down pipe size
=
150
mm
From fig I3, Rain water head Depth (Interpolating where necessary)
=
129
mm
Rain water Head Depth increased to comply with Note 1 Fig I2
(RWH depth to be >= 1.25*DP dia.)
=
1.25*150
mm
=
188
mm
From fig I3, Rain water head Length at slope 1:200
=
169
mm
Rain water Head Length increased to fit the DP 150 +20
=
170
mm
Rain water Head Width
=
300
mm
Summary
Down Pipe Size
=
150
mm
Box Gutter Width
=
300
mm
Box gutter minimum Depth
=
155
mm
Rain Water Head Depth
=
188
mm
Rain Water Head Length
=
170
mm
Rain Water Head Width
=
300
mm
James Crint
Head Honcho
Hydraulic Department