Catchment area (effective) (roof drainage) - Revision history

Joceil.infante: /* References: */

2017-04-13T07:53:01Z

‎References:

2017-04-13T07:46:15Z

2017-04-13T02:36:21Z

2017-04-13T02:35:23Z

2017-04-11T09:08:37Z

2017-04-11T09:07:01Z

2017-04-11T08:41:02Z

2017-04-11T07:39:00Z

2017-04-11T07:21:01Z

2017-04-11T07:19:08Z

← Older revision		Revision as of 07:53, 13 April 2017
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	# SS 525:2006 Code of Practice for Drainage of roofs		# SS 525:2006 Code of Practice for Drainage of roofs
	# ASTM A112.6.9 Standard for Siphonic Roof drainage Systems		# ASTM A112.6.9 Standard for Siphonic Roof drainage Systems
		+	# ASPE Standard 45 Siphonic Roof Drainage

@@ Line 12: / Line 12: @@
 [[File:Catchment-Area-Flat-Roof.jpeg|Catchment-Area-Flat-Roof.jpeg]]
-Flat roof: <math>A = A_h</math>
+'''Flat roof:''' <math>A = A_h</math>
@@ Line 50: / Line 50: @@
 [[File:Catchment-Area-Sloping-Roof-diagram.jpeg]]
-<math>A = A_h + \frac{A_V}{2}</math>
+'''Sloping roof:''' <math>A = A_h + \frac{A_V}{2}</math>
@@ Line 58: / Line 58: @@
 [[File:Catchment-Area-Valley.jpeg]]
-Valley gutter: <math> A = A_h,1 + A_h,2 + \frac{1}{2} (A_v,2 - A_v,1)</math>
+'''Valley gutter:''' <math> A = A_h,1 + A_h,2 + \frac{1}{2} (A_v,2 - A_v,1)</math>
 Run off from any vertical wall should be added to the effective catchment area.

@@ Line 75: / Line 75: @@
 For an enclosed area, the effective catchment area will be its plan area unless the surrounding walls are of unequal height. In the latter case, the value of A should be increased by half the area in the elevation by which the higher wall exceeds the lower wall.
-'''Small Roofs'''
+'''Small Roofs.'''
 For small roof area not exceeding 6 sq.mts. and no other area drains onto it, gutters and rainwater pipes may be omitted from a roof at any height.
-'''Tall buildings'''
+'''Tall buildings.'''
 Gutters and rainwater pipes may be omitted from tall structures where runoff would be dispersed before the ground. Such runoff should be directed so as to avoid undesirable pattern staining and splashing of windows.

← Older revision		Revision as of 02:35, 13 April 2017
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	*Catchment area can be a flat or sloping roof/ surfaces and also includes vertical surfaces.		*Catchment area can be a flat or sloping roof/ surfaces and also includes vertical surfaces.

−	*Effective catchment area for vertical surfaces	+	*Effective catchment area for vertical surfaces. Single wall shall be 50% of its total surface area up to a maximum exposed height of 33feet (10metres).
−	Single wall shall be 50% of its total surface area up to a maximum exposed height of 33feet (10metres).

← Older revision		Revision as of 09:08, 11 April 2017
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	Run off from any vertical wall should be added to the effective catchment area.		Run off from any vertical wall should be added to the effective catchment area.
−
−	~~In area where wind is taken into account in rainfall calculations, where rain driven against a wall by the wind is taken;~~

	*'''Vertical surfaces'''		*'''Vertical surfaces'''

@@ Line 10: / Line 10: @@
 == Effective Catchment Area ==
-'''FLAT ROOFS'''
+*'''FLAT ROOFS'''
 Flat roof: <math>A = A_h</math>
 '''SLOPING ROOFS'''
 The effective area, '''''A''''', roof draining to an eaves or parapet gutter (''should be calculated using the table below'')
 {| class="wikitable"
@@ Line 47: / Line 50: @@
 [[File:Catchment-Area-Sloping-Roof-diagram.jpeg]]
-'''VALLEY GUTTER'''
+*'''VALLEY GUTTER'''
 For valley gutter, one side of the roof will tend to be exposed to the wind and the other will tend to be sheltered. The methos of calculating the effective catchment are illutrated on the Figure below;
 [[File:Catchment-Area-Valley.jpeg]]
 Run off from any vertical wall should be added to the effective catchment area.
@@ Line 58: / Line 65: @@
 In area where wind is taken into account in rainfall calculations, where rain driven against a wall by the wind is taken;
-'''Vertical surfaces'''
+*'''Vertical surfaces'''
 The effective catchment area of a single wall should be taken as 50% of its area, up to a maximum height of 10 meters.
 Where two or more walls from an angle or bay, the direction of the wind should be assumed to be such that the walls considered together present the maximum vertical area to the rain, as illustrated in Figure below;
 [[File:Catchment-Area-Effective-Vertical-Surfaces.jpeg]]
 <math>A= \frac{1}{2} \surd (A^2_{v,1} + A^2_{v,2} - 2A_{v,1} - A^2_{v,2} \cos \theta)</math>

@@ Line 7: / Line 7: @@
 Single wall shall be 50% of its total surface area up to a maximum exposed height of 33feet (10metres).
-*Effective Catchment Area
-- Flat roofs
+== Effective Catchment Area ==
 [[File:Catchment-Area-Flat-Roof.jpeg]]
+Flat roof: <math>A = A_h</math>
-- Sloping roofs
+'''SLOPING ROOFS'''
 The effective area, '''''A''''', roof draining to an eaves or parapet gutter (''should be calculated using the table below'')
@@ Line 46: / Line 48: @@
 [[File:Catchment-Area-Sloping-Roof-diagram.jpeg]]
-- For valley gutter, one side of the roof will tend to be exposed to the wind and the other will tend to be sheltered. The methos of calculating the effective catchment are illutrated on the Figure below;
 [[File:Catchment-Area-Valley.jpeg]]
@@ Line 60: / Line 65: @@
 <math>A= \frac{1}{2} \surd (A^2_{v,1} + A^2_{v,2} - 2A_{v,1} - A^2_{v,2} \cos \theta)</math>
-Where <math>A_{v,1}</math> and <math>A_{v,2}</math> are areas of the vertical walls, as shown, contributing to the flow of the gutter.
+Where <math>A_{v,1}</math> and <math>A_{v,2}</math>  are areas of the vertical walls, as shown, contributing to the flow of the gutter.

← Older revision		Revision as of 07:39, 11 April 2017
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	[[File:Catchment-Area-Effective-Vertical-Surfaces.jpeg]]		[[File:Catchment-Area-Effective-Vertical-Surfaces.jpeg]]
		+	<math>A= \frac{1}{2} \surd (A^2_{v,1} + A^2_{v,2} - 2A_{v,1} - A^2_{v,2} \cos \theta)</math>
		+
		+	Where <math>A_{v,1}</math> and <math>A_{v,2}</math> are areas of the vertical walls, as shown, contributing to the flow of the gutter.
		+

	For an enclosed area, the effective catchment area will be its plan area unless the surrounding walls are of unequal height. In the latter case, the value of A should be increased by half the area in the elevation by which the higher wall exceeds the lower wall.		For an enclosed area, the effective catchment area will be its plan area unless the surrounding walls are of unequal height. In the latter case, the value of A should be increased by half the area in the elevation by which the higher wall exceeds the lower wall.

@@ Line 57: / Line 57: @@
 Where two or more walls from an angle or bay, the direction of the wind should be assumed to be such that the walls considered together present the maximum vertical area to the rain, as illustrated in Figure below;
-[[File:Catchment-area-Vertical-Surfaces.jpeg]]
+[[File:Example.jpg]]
 For an enclosed area, the effective catchment area will be its plan area unless the surrounding walls are of unequal height. In the latter case, the value of A should be increased by half the area in the elevation by which the higher wall exceeds the lower wall.