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SCHOOL MAIN LIBRARY BUILDINGSCHOOL MAIN LIBRARY BUILDING

““DESIGN OF RAINWATER COLLECTION DESIGN OF RAINWATER COLLECTION SYSTEM”SYSTEM”

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1.0. PROBLEM TITLE:

TO DESIGN A UNIVERSITY LIBRARY:

1.) GREEN ARCHITECTURE1.A.) PASSIVE COOLING

1.A.A.) NATURAL LIGHTING AND VENTILATION

1.A.B.) LANDSCAPING / POND1.A.C.) ORIENTATION

2.) CHARACTER MUST FIT ITS USAGE

3.) WATER RECYCLE:ATLEAST HELPS IN SAVING RAIN WATERBY CONSIDERING THE

RAIN WATER CATCHMENT

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1.) GREEN ARCHITECTURE1.A.) PASSIVE COOLING

: WIDE OPENINGS – MAXIMIZING WINDOWS TO TRANSMIT NATURAL LIGHT AND VENT.

: ROOFING MATERIALS – USE CEMENT FIBER ROOFING (PLACA ROMANA)

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1.B.) LANDSCAPE SURROUNDINGS / POCKET GARDENS

1.B.) PROPER LANDSCAPING

: MAKES THE ATMOSPHERE / SURROUNDING COOLER

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1.) GREEN ARCHITECTURE (RENEWABLE ENERGY)

1.C.) ORIENTATION

maximize opening along NORTH,

MINIMUM SPACES & EXPOSURE ATAFTERNOON SUN

MAIN ENTRANCE

ALONGNORTH EAST

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1.) CHARACTER of the BUILDING

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1.) RAIN WATER CONSIDERATION

SLOPE

BUTTERFLY

ROOF

SLOPE

PROBLEM?

WHAT IS THE

PROPER SIZE OF THE MIDDLE GUTTER?

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DESIGN OF BUTTERFLY DESIGN OF BUTTERFLY GUTTERGUTTER

CALCULATING THE SIZE OF THE ROOF CALCULATING THE SIZE OF THE ROOF GUTTERGUTTER

CALCULATE THE MAXIMUM SPACINGCALCULATE THE MAXIMUM SPACING

OF THE DOWNSPOUTOF THE DOWNSPOUT

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CALCULATING CALCULATING THE SIZE OF THE THE SIZE OF THE

ROOF GUTTERROOF GUTTER

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CALCULATING CALCULATING THE SIZE OF THE ROOF GUTTERTHE SIZE OF THE ROOF GUTTER

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GUTTER SIZING CONSIDERATIONGUTTER SIZING CONSIDERATION

In sizing gutters, the following considerations apply for typical section lengths of 8 to 10 feet ( In sizing gutters, the following considerations apply for typical section lengths of 8 to 10 feet ( 2.41 to 3.0m):2.41 to 3.0m):

1. Spacing and size of outlet openings. (The gutter can never be any more effective than the 1. Spacing and size of outlet openings. (The gutter can never be any more effective than the outlet and downspout selected to drain it. Downspout sizes must not exceed the bottom width outlet and downspout selected to drain it. Downspout sizes must not exceed the bottom width of the rain gutters.)of the rain gutters.)

2. Slope of the roof. (The gutter must be of such a design and location that water from a steep 2. Slope of the roof. (The gutter must be of such a design and location that water from a steep pitched roof will not by its own velocity tend to overrun the front edge.)pitched roof will not by its own velocity tend to overrun the front edge.)

3. Style of gutters to be used. (All gutters are not effective for their full depth and width.)3. Style of gutters to be used. (All gutters are not effective for their full depth and width.)

4. Maximum length of gutter. (50 ft.(15.2 m) between ends or expansion joints is the limit 4. Maximum length of gutter. (50 ft.(15.2 m) between ends or expansion joints is the limit unless the system is especially designed to accommodate the greater expansion, the larger unless the system is especially designed to accommodate the greater expansion, the larger flow and the need for special supports.)flow and the need for special supports.)

5. Rain Gutter support capability. (Supports should be based on full capacity of the gutter. Ice 5. Rain Gutter support capability. (Supports should be based on full capacity of the gutter. Ice load capacity also affect the size and strength of the system.)load capacity also affect the size and strength of the system.)

Sloped gutters may be. Formulae for flow in gutters with different pitch are not available. The Sloped gutters may be. Formulae for flow in gutters with different pitch are not available. The capacity of a gutter with 1/16 in./ft.(5.21 mm/m) or less pitch is taken as that of a level gutter capacity of a gutter with 1/16 in./ft.(5.21 mm/m) or less pitch is taken as that of a level gutter even though it is somewhat greater. even though it is somewhat greater.

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Reference:Reference:Plumbing and Heating Calculations by F. HallPlumbing and Heating Calculations by F. Hall

1.) Calculating for the size of the roof gutter.1.) Calculating for the size of the roof gutter.Determine the effective area of the roof that you intend to drain Determine the effective area of the roof that you intend to drain

to your rainwater tank. Sometimes the roof may be to your rainwater tank. Sometimes the roof may be complicated that you just use a part of it and not its entirety. If complicated that you just use a part of it and not its entirety. If you cannot do the measurement, hire someone who knows you cannot do the measurement, hire someone who knows how to use a measuring tape and can do a bit of trigonometry.how to use a measuring tape and can do a bit of trigonometry.

The equation is: The equation is: Area of the roof = Effective width x lengthArea of the roof = Effective width x length

Where Effective width = b +a/2Where Effective width = b +a/2

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2.) Solve for the flow load (Q).2.) Solve for the flow load (Q). Use the equation: Use the equation: Q = A x R/3600Q = A x R/3600 Where Where Q = Rate of flow in cubic meter Q = Rate of flow in cubic meter

per second or liters per secondper second or liters per second A = Area of the roof in square metersA = Area of the roof in square meters R = Rate of rainfall in the localityR = Rate of rainfall in the locality Use the data from PAGASA. If none is Use the data from PAGASA. If none is

available, use 0.125 meter per houravailable, use 0.125 meter per hour

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3.) Solve for the area of gutter (Ag). Use the equation: 3.) Solve for the area of gutter (Ag). Use the equation: Where: Where: Ag = Area of gutter in square millimeterAg = Area of gutter in square millimeter Q = Rate of flow in liters per secondQ = Rate of flow in liters per second B = Width of gutter; use either 100mm or B = Width of gutter; use either 100mm or

150mm150mm

4.) Solve for the Depth of water flow (Dwf).4.) Solve for the Depth of water flow (Dwf). Use the equationUse the equation: Dwf = Ag/B: Dwf = Ag/B

Where: Dwf = Depth of water flow in the gutter millimeterWhere: Dwf = Depth of water flow in the gutter millimeter Ag = Area of gutter in square millimeterAg = Area of gutter in square millimeter B = Width of gutter usedB = Width of gutter used

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5.) Solve for the depth gutter (Dg).5.) Solve for the depth gutter (Dg). Use the equation: Use the equation: Dg = 2(Dwf) + 60mmDg = 2(Dwf) + 60mm Where: Dg = Depth of gutter in millimetersWhere: Dg = Depth of gutter in millimeters Dwf = Depth of water flow in Dwf = Depth of water flow in

millimetermillimeter 60mm = for freeboard or allowance60mm = for freeboard or allowance

Now you can draw the profile of your gutter based Now you can draw the profile of your gutter based on the calculated depth and width of the gutter. If on the calculated depth and width of the gutter. If you intend to buy ready-made gutters, make sure its you intend to buy ready-made gutters, make sure its dimension will not be less than of your calculated dimension will not be less than of your calculated size.size.

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Calculating for the maximum spacing of the Calculating for the maximum spacing of the downspout.downspout.

1.) This process allows you to check on the spacing of 1.) This process allows you to check on the spacing of your downspouts, to make sure that you do not go your downspouts, to make sure that you do not go beyond the acceptable limit.beyond the acceptable limit.

Solve for the rate of runoff (Q) of a 1 meter of roof.Solve for the rate of runoff (Q) of a 1 meter of roof. Use the equation : Use the equation : Q = A x R / 3600Q = A x R / 3600 Where:Where:

Q = Rate of runoff in liter per second per meterQ = Rate of runoff in liter per second per meter

A = Area of roof with a slice length of 1 meterA = Area of roof with a slice length of 1 meter

R = Rainfall intensity in meter per hour R = Rainfall intensity in meter per hour

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2.) Solve for the maximum spacing of downspouts.2.) Solve for the maximum spacing of downspouts. Us e the equation : Us e the equation : S = 2(Cg/Q)S = 2(Cg/Q) Where:Where: S = Maximum spading of S = Maximum spading of

downspouts in meters downspouts in meters Cg = Capacity of gutter;Cg = Capacity of gutter; For 100mm wide gutter, use 0.7 For 100mm wide gutter, use 0.7

lps,lps, For 150mm wide gutter, use 2.3 For 150mm wide gutter, use 2.3

lpslps Q = Rate of runoff in liters per secondQ = Rate of runoff in liters per second

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Calculating for the Diameter of the downspout (Dds).

This calculation allows you to determine the maximum size of the pipe to use as a downspout in relation to the commercially available pipe diameter.

Use the equation:

Ax1000Dds = 5 -----------

3.2

Where: Dds = Diameter of downspout A = Area of roof

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Calculating for the capacity of the rainwater taskCalculating for the capacity of the rainwater task

1.) Solve for the Rate of flow (Q).1.) Solve for the Rate of flow (Q). Use the equation: Use the equation: Q = (A x R / 60) 1000Q = (A x R / 60) 1000 Where:Where: Q = Rate of flow in liters per minuteQ = Rate of flow in liters per minute A = Area of roof in square metersA = Area of roof in square meters R = Rainfall intensity in meter per hourR = Rainfall intensity in meter per hour 2.) Solve for the capacity of the rainwater tank (Cwt).2.) Solve for the capacity of the rainwater tank (Cwt). Use the equation: Use the equation: Cwt = Q x 20 minutesCwt = Q x 20 minutes

Where:Where: Cwt = Capacity of rainwater tank in liters Cwt = Capacity of rainwater tank in liters Q = Rate of flow in liters per minuteQ = Rate of flow in liters per minute 20 minutes = the assumed longest storm period20 minutes = the assumed longest storm period

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SAMPLE COMPUTATIONSAMPLE COMPUTATION

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SOLVING FOR SOLVING FOR THE EFFECTIVE THE EFFECTIVE

ROOF AREAROOF AREA

ROOF – 1ROOF – 116.50x16.20 = 267.30 sq.m.16.50x16.20 = 267.30 sq.m.

ROOF – 2ROOF – 2 8.10x21.09 = 170.83 sq.m. 8.10x21.09 = 170.83 sq.m.2(1.95)x13.50 2(1.95)x13.50 = 52.65 sq.m.= 52.65 sq.m. =118.18 sq.m. =118.18 sq.m.

ROOF TOTALROOF TOTAL267.30 + 118.18 = 385.50sq.m.267.30 + 118.18 = 385.50sq.m.

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SOLVE FOR THE FLOW LOAD (Q)SOLVE FOR THE FLOW LOAD (Q)

Use the equation: Use the equation: Q = A x R / 3600Q = A x R / 3600Where :Where :

Q = Rate of flow in cubic meter per second or liters per secondQ = Rate of flow in cubic meter per second or liters per second A = Area of the roof in square metersA = Area of the roof in square meters

R = Rate of rainfall in the localityR = Rate of rainfall in the localityUse the data from PAGASA. If none is available, Use the data from PAGASA. If none is available,

use 0.125 meter per houruse 0.125 meter per hour

Q = 385.50 x 0.125 / 360Q = 385.50 x 0.125 / 360 -3 3 -3 3

= 1.33 x 10 m/sec = 1.33 x 10 m/secor or

1.33 LPS (Liter Per Second)1.33 LPS (Liter Per Second)

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Solving for the WATER INSIDE THE GUTTER

Use the equation: 2 Q

AG = 3 ----------- x B 0.0001

2 1.33

AG = 3 ----------- x 400 = 4.136 sq. mm. 0.0001

Let: B = 400 mm, Q = 1.33 Lit / sec

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Solving for the

DEPTH OF WATER FLOW (DWF)

Use the equation:

AG

DWF = ----------- B

AG = 4.136 sq. mm.

B = 400 mm,

4.136 sq. mm.

DWF = -------------------- = 10.340 mm. 400 mm.

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Solving for the

DEPTH OF

OUTLET (DG)Use the equation:

DG = 2 (DWF) + 60

DG = 2 (10.340) + 60

DG = 80.68 mm OR 100 mm

100 mm. depth

Therefore:100mm depth is sufficient:

But we Adapted 340 mm depth

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Calculating for the DIAMETER OF THE DOWNSPOUT (DdS)

Use the equation: 2 A x 1000

Dds = 5 ----------- 3.2 Where Dds = Dia. Of downspout

AT = Area of Roof

2 385.5 x 1000

Dds = 5 ---------------- = 107.73 mm. use 6 inches Dia. 3.2

Therefore: 1 unit - 6” dia. Both sides is enoughBut we adapted 2 units – 6” dia. Both sides

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Solving for the capacity of the RAINWATER TANK

SOLVING FOR RATE OF FLOW (Q) OF BUTTERFLY ROOF

385.50 x 0.125

Q = ------------------ 1000 = 803.125 Liters per minute 60

Where :A ROOF = 385.50 R = .125

A ROOF x R

Q = ------------------ 1000 60

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Solving for the capacity of the RAINWATER TANK / CATCHMENT

SOLVING FOR THE CAPACITY OF TANK

Crwt = 803.125 x 20 = 16, 062.5 Liters

Where :

C rwt = 803.125 R = 20 minutes

SOLVING FOR VOLUME OF RAINWATER TANK (Vrwt)

16, 062.5 Liters

Vrwt = ---------------------------- = 16.0625 cu. M. 1000 Liters per cu. M.

Therefore: PROVIDE A RAINWATER TANK WITH ACAPACITY OF 16,062.50 LITERS OR A VOLUME OF16. 0625 CU. METERS.