S T A N D A R D S

AS/NZS 3500.3.2:1998National plumbing and drainagePart 3.2: Stormwater drainage - Acceptable solutionsAS 3500.3.1:1998National plumbing and drainagePart 3.1: Stormwater drainage - Performance requirementsAS/NZS 2179.1:1994Specifications for rainwater goods, accessories and fastenersPart 1: Metal shape or sheet rainwater goods, and metal accessories and fasteners

1.1 SCOPE This Standard specifies requirements for pre-painted metal, metal and organic film/metal laminated shape or sheet rainwater goods, and metal accessories and fasteners.AS/NZS 2179.1:1994Specifications for rainwater goods, accessories and fastenersPart 1: Metal shape or sheet rainwater goods, and metal accessories and fasteners3.8 EFFECTIVE CROSS-SECTIONALAREA The effective cross-sectional area (to the nearest 100 mm) for each nominal size of eaves gutter, valley gutter and downpipe shall be supplied by the manufacturer. The effective cross-sectional area for each shall be as follows:(a) For an eaves gutter and support system(i) it is the cross-sectional area beneath a line not less than 10 mm below the overflow, e.g. front bead, gutter back or bottom of overflow slots; or4.1 GENERAL One or more of the performance tests shall be used to demonstrate the compliance of a gutter or downpipe and support system

1 SCOPE This Standard specifies the performance requirements for materials and products, and design and installation of roof drainage systems, surface drainage systems and subsoil drainage systems. AS 3500.3.1:1998National plumbing and drainagePart 3.1: Stormwater drainage - Performance requirements

6 PERFORMANCE REQUIREMENTS6.1 Roof drainage systems6.1.1 Average recurrence interval (ARI) Roof drainage systems shall be designed and installed in accordance with the following:(a) Where it is unlikely that adverse effects of stormwater flows would result in significant inconvenience or injury to people or damage to property, for rainfall events having an ARI of not less than 20 years.(b) Where it is likely that adverse effects of stormwater flows would result in significant inconvenience or injury to people or damage to property, for rainfall events having an ARI of not less than 100 years.AS 3500.3.1:1998National plumbing and drainagePart 3.1: Stormwater drainage - Performance requirements6.1.2 Overflow devices or measures Overflow devices or measures shall be installed where overtopping of the roof drainage system could cause significant monetary loss, property damage or personal injury, and shall be designed in accordance with Clause 6.1.1(b) taking into account the effect of obstructions and blockages.

AS/NZS 3500.3.2:1998National plumbing and drainagePart 3.2: Stormwater drainage -Acceptable solutionsBuilding Code of Australiaprimary referenced Standard

AS/NZS 3500.3.2:1998SECTION 3ROOF DRAINAGE SYSTEMS - DESIGN

ARI = 20 years

rainfall intensity = 210 mm/hSYDNEY210ARI = 20 years

+ 6 x 4 = 24 15 x 8 = 120 (Ah) 144 m rainfall intensity = 210 mm/hPitch 23.5ARI = 20 years

23.51.21x 1.2 (F)(Ac) 174 m ARI = 20 years

Gradient 1 : 500Smoothline Ae = 5900 mm4.8 EAVES GUTTERS Eaves gutters shall be installed as follows:(a) Gradients Deviations from nominal gradients shall be smooth and not cause permanent ponding.NOTES:1. Where a building is likely to move due to reactive soils, gradients may need to be not flatter than -(a) 1:250 to achieve an effective gradient not flatter than 1:500; or(b) 1:500 to achieve an effective gradient with no permanent ponding.ARI = 20 years

ARI = 20 years

Acdp = 28 m174 / 28 = 7 min number of downpipesEFFECTIVE CROSS-SECTIONAL AREA OF EAVES GUTTER (Ae) 1000 mmFOR GRADIENTS OF 1 : 500 AND STEEPERCATCHMENT AREA PER VERTICAL DOWNPIPE (Ac) mEFFECTIVE CROSS-SECTIONAL AREA OF EAVES GUTTER (Ae) 1000 mmFOR GRADIENTS FLATTER THAN 1 : 500TOTAL FLOW IN EAVES GUTTER (L / s)DESIGN RAINFALL INTENSITY mm / h5.928FIGURE 3.6 REQUIRED SIZE OF EAVES GUTTERSARI = 20 years

HPHPHPHPHPHPHPDP - ADP - BDP - CDP - DDP - EDP - FDP - G

min downpipe size = 85 diaARI = 20 years

As-c (downpipe G) = 28 m

281.65total flow = 1.65 L/s

1.65 / 4 = 0.4 L / sAve flow per metre of gutterLength of gutter (G) = 4 m4

hf = 14 mm

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