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AS/NZS 3500.3:2021


Plumbing and drainage, Part 3: Stormwater drainage

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Sets out the requirements for materials, design, installation and testing of roof drainage systems, surface drainage systems and subsoil drainage systems to a point of connection. KEYWORDS: Plumbing; Drainage; Stormwater; Roof, surface and subsoil drainage.
Published: 28/05/2021
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Table of contents
Cited references
Content history
Table of contents
About this publication
1 Scope and general
1.1 Scope
1.2 Application
1.2.1 Australia
1.2.2 New Zealand
1.3 Normative references
1.4 Terms and definitions
1.5 Abbreviations
1.5.1 General
1.5.2 Plastics abbreviations
1.6 Notation
1.6.1 Quantity symbols
1.6.2 Flow chart symbols
1.6.3 Gradients
1.7 Identification of piping
2 Materials and products
2.1 Scope of section
2.2 Selection and use
2.3 Roof drainage system
2.3.1 Roof drainage system components
2.3.2 Downpipes
2.3.3 Accessories and fasteners
2.4 Stormwater drains (non-pressure)
2.5 Rising mains (pressure)
2.6 Subsoil drains
2.7 Joints
2.7.1 Resin adhesives General Sealants Silver brazing alloy Soft solder Solvent cement and priming fluid
2.7.2 Types Bolted gland Cement mortar Elastomeric seals Epoxy resin Fusion welded Mechanical coupling Metal-banded flexible coupling Silver brazed Soft soldered Solvent cement
2.8 Valves
2.8.1 Gate and globe
2.8.2 Non-return
2.8.3 Sluice
2.8.4 Wedge gate
2.9 Concrete and mortar
2.9.1 Concrete
2.9.2 Cement mortar
2.9.3 Chemical admixtures
2.9.4 Water for concrete and mortar
2.9.5 Steel reinforcement
2.10 Embedment material
2.10.1 Site stormwater drains
2.10.2 Subsoil drains
2.11 Trench fill
2.12 Miscellaneous
2.12.1 Clay building bricks
2.12.2 Concrete masonry units
2.12.3 Cover and sump grates
2.12.4 External protective coating
2.12.5 Fibreglass-reinforced plastic tanks
2.12.6 Geotextiles
2.12.7 Polyethylene sleeving
2.12.8 Precast or prefabricated pits and arresters Concrete Corrugated metal Other materials
2.12.9 Timber
2.13 Filters for subsoil drains
2.13.1 Filter material
2.13.2 Geotextile filters
3 Roof drainage systems — Design
3.1 Scope of section
3.2 General method
3.3 Meteorological criteria
3.3.1 General
3.3.2 Snowfall effects
3.3.3 Wind effects
3.3.4 Design probabilities
3.3.5 Rainfall intensity Australia New Zealand
3.4 Catchment area
3.4.1 General
3.4.2 Three-dimensional representation
3.4.3 Roof Flat roof Single sloping roof Two adjacent sloping roofs
3.4.4 Vertical wall(s) and roof Vertical wall with a flat roof Vertical wall with a sloping roof Vertical walls at right angles to each other
3.4.5 Higher catchment area
3.4.6 Green, landscaped or garden roofs
3.5 Eaves gutter systems
3.5.1 General
3.5.2 Design procedure
3.5.3 Vertical downpipes
3.5.4 Effective cross-sectional area of eaves gutters
3.6 Valley gutters
3.6.1 Limitations
3.6.2 Design procedure
3.6.3 Effective width
3.7 Box gutter systems
3.7.1 General
3.7.2 Freeboard
3.7.3 Limitations
3.7.4 Design procedure
3.7.5 Hydraulic capacity
3.7.6 Layout
3.7.7 Overflow devices Hydraulic capacity Operation
3.7.8 Downpipes
3.8 Balcony and terrace areas
4 Roof drainage systems — Installation
4.1 Scope of section
4.2 Installation
4.3 Thermal variation
4.3.1 General
4.3.2 Expansion joints
4.4 Corrosion
4.4.1 Corrosion due to direct contact
4.4.2 Corrosion due to drainage
4.4.3 Corrosion due to crevices
4.4.4 Corrosion due to chemical incompatibility
4.5 Installation and testing
4.5.1 Installation
4.5.2 Testing
4.5.3 Eaves gutters
4.5.4 Box gutters
4.5.5 Valley gutters
4.5.6 Downpipes
4.6 Overflow devices
4.7 Joints for metal components
4.7.1 General
4.7.2 Type of joints Soldered Sealant Laps
4.7.3 Aluminium alloys
4.7.4 Aluminium/zinc and aluminium/zinc/magnesium alloy-coated steel
4.7.5 Stainless steel
4.7.6 Zinc and zinc-coated steel
4.8 Joints for other components
4.9 Support systems
4.9.1 Types
4.9.2 Criteria
4.9.3 Support systems for eaves gutters
4.9.4 Support systems for box gutters
4.9.5 Support systems for valley gutters
4.9.6 Support systems for downpipes Vertical Graded
5 Surface water drainage systems — Design
5.1 Scope of section
5.2 Design
5.2.1 Methods
5.2.2 General criteria
5.2.3 Design rainfall intensity
5.3 Layout — General criteria
5.3.1 Roof areas
5.3.2 Other than roof areas
5.3.3 Ponding
5.3.4 Entry into buildings
5.3.5 Containment of harmful substances
5.3.6 Inlet and pit locations
5.3.7 Sanitary drainage system
5.4 General method
5.4.1 General
5.4.2 Overland flood path
5.4.3 Average exceedance probability
5.4.4 Time of concentration
5.4.5 Rainfall intensity
5.4.6 Run-off coefficients
5.4.7 Catchment area
5.4.8 Determination of design flows
5.4.9 Design of open channels
5.4.10 Design of inlets Sag pits On-grade pits
5.4.11 Design of pipe drains General Design procedure
5.4.12 Design of surcharge outlets (Australia only) General Design procedure
5.5 Nominal method
6 Surface and subsoil drainage systems — Installation
6.1 Scope of section
6.2 General requirements
6.2.1 Products and joints
6.2.2 Terminology
6.2.3 Trench width
6.2.4 Over-excavation
6.2.5 Cover
6.2.6 Proximity to other services
6.2.7 Shoring and underpinning buildings
6.2.8 Installation near and under buildings
6.2.9 Water-charged ground
6.2.10 Trench fill
6.2.11 Backfilling
6.2.12 Excavation near point of connection
6.2.13 Corrosive areas
6.3 Site stormwater drains
6.3.1 General Site stormwater drains Site stormwater pipes
6.3.2 Connections to pits and arresters
6.3.3 Minimum diameter
6.3.4 Gradients
6.3.5 Embedment Materials Installation
6.3.6 Cover under buildings
6.3.7 In easements and public places
6.3.8 Disconnection
6.3.9 Testing
6.4 Subsoil drains
6.4.1 General
6.4.2 Embedment Materials Installation Disconnection
7 Surface water and subsoil drainage systems — Ancillaries
7.1 Scope of section
7.2 Paved surfaces
7.3 Reflux valves
7.3.1 Purpose
7.3.2 Location
7.3.3 Criteria
7.4 Inspection openings
7.4.1 Location
7.4.2 Size
7.4.3 Access
7.4.4 Plugs or caps
7.5 Stormwater pits, inlet pits and arresters
7.5.1 Purpose Stormwater pits Inlet pits Arresters
7.5.2 Size Stormwater and inlet pits Arresters
7.5.3 Falls across pits
7.5.4 Inlets
7.5.5 Materials and construction Rectangular or square pits and arresters Circular pits Conduits and channels Ladders Cement rendering Upper walls of stormwater pits Access openings Construction joints Inserts Connections
7.6 Surcharge outlets
7.7 Junctions
7.7.1 General
7.7.2 Square junctions
7.8 Jump-ups
7.9 Anchor blocks
7.10 On-site stormwater detention systems
7.10.1 General criteria
7.10.2 Below-ground systems
7.10.3 Materials
8 Pumped systems
8.1 Scope of section
8.2 General requirements
8.3 Wet wells
8.3.1 General
8.3.2 Construction and materials
8.3.3 Base
8.3.4 Cover
8.3.5 Ladders
8.3.6 Combined effective storage
8.3.7 Alarm
8.3.8 Inlet
8.3.9 Sealing
8.4 Pumps
8.5 Rising mains
8.6 Electrical connection
9 Site Testing
9.1 Scope of section
9.2 Downpipes, site stormwater drains and drains within or under buildings
9.3 Test criteria
9.3.1 Downpipes within buildings
9.3.2 Site stormwater drains, drains within and under buildings, and main internal drains
9.3.3 Rising mains
9.4 Procedure
9.4.1 Water test
9.4.2 Air test
10 Siphonic drainage systems
10.1 Scope of section
10.1.1 General
10.1.2 Design probabilities
10.1.3 Design methods
10.1.4 Materials
10.2 Requirements
10.2.1 Freeboard
10.2.2 Balancing
10.2.3 Available head
10.2.4 Calculation of flows at inlets
10.2.5 Minimum pressure in pipes
10.2.6 Minimum velocity
10.2.7 Overflow capacity
10.2.8 Minimum pipe size
Appendix A
Appendix B
B.1 Scope
B.2 Roof plan
B.2.1 Building with fewer than four floor levels
B.2.2 Buildings with four or more floor levels
B.3 Site plan
B.4 Catchment plan
B.5 Computation sheets
Appendix C
C.1 Scope
C.2 Procedures
C.2.1 Australia
C.2.2 New Zealand
Appendix D
D.1 Scope
D.2 Selected place references
Appendix E
E.1 Scope
E.2 Selected place references
Appendix F
F.1 Scope
F.2 Full length (continuous) overflows
F.3 Specifically located overflows
Appendix G
G.1 Scope
G.2 Example
G.2.1 Problem
G.2.2 Case 1 — Sloping eaves gutter
G.2.2.1 Calculation
G.2.2.2 Solution
G.2.3 Case 2 — Flat eaves gutter
G.2.3.1 Calculation
G.2.3.2 Solution
Appendix H
Appendix I
I.1 Scope
I.2 Example 1 — Box gutters, rainheads and downpipe
I.2.1 Problem
I.2.2 Calculation
I.3 Example 2 — Box gutters, sump/side overflow devices and downpipes
I.3.1 Problem
I.3.2 Calculation
I.4 Example 3 — Box gutters, sump/high-capacity overflow devices and downpipes
I.4.1 Problem
I.4.2 Calculation
Appendix J
J.1 Scope
J.2 Example 1 — Nominal method
J.2.1 Problem
J.2.2 Solution
J.2.2.1 Layout
J.2.2.2 Site stormwater drains
J.2.3 Stormwater pits
J.3 Example 2 — General method — Villa home development
J.3.1 Problem
J.3.2 Assumptions
J.3.3 Solution
J.3.3.1 Preliminary
J.3.3.2 Procedure
J.4 Example 3 — General method — Warehouse
J.4.1 Problem
J.4.2 Assumptions
J.4.3 Solution
J.4.3.1 Preliminary
J.4.3.2 Procedures
Appendix K
Appendix L
L.1 Scope
L.2 Purpose
L.3 Types
L.4 Layout
L.4.1 General arrangement
L.4.2 Drains
L.4.3 Specifications — Filters
L.5 Design considerations
L.5.1 Drain dimensions and spacings
L.5.2 Design of conduits
L.5.3 Pipe gradient
Appendix M
M.1 Scope
M.2 Protection of works
M.2.1 Roof drainage systems
M.2.2 Surface water drainage and subsoil drainage systems
M.3 Discharge point criteria
M.3.1 Position and manner of discharge
M.3.2 Stormwater drainage plans
M.4 Transport, handling and storage
M.5 Inspection and cleaning
M.6 Alterations and disconnection
M.7 Layout
M.7.1 General
M.7.2 Influences on layout
M.8 Surface water drainage systems — Design
M.8.1 Concentrated discharges to streets
M.8.2 Snowfall effects
M.9 Subsoil drainage systems — Design
M.10 Erosion and sediment controls
M.11 Other than stable grounds
M.12 Above-ground systems
Appendix N
N.1 General
N.2 General design procedure for siphonic roof drainage systems
N.2.1 Design procedure
N.2.2 Design parameters
N.2.2.1 Basis for calculations
N.2.2.2 Gutter/inlet/pipe sizing
N.2.2.3 Priming
N.2.2.4 Sloping gutters
N.2.2.5 Low flow conditions
N.2.2.6 Siphonic roof inlet positions
N.2.2.7 Downpipes
N.2.3 Components
N.2.3.1 Inlets
N.2.3.2 Access points for cleaning
N.2.3.3 Pipe/fittings
N.2.3.4 Reducers or expanders
N.2.4 Validation of design — Outline checks
N.2.5 Installation
N.2.5.1 Blockage prevention
N.2.5.2 Reducers or expanders
N.2.5.3 Fixings and support
N.2.5.4 Changes during construction
N.2.6 Testing and commissioning
N.2.6.1 Inspection
N.2.6.2 Hydrostatic/air test
N.2.6.3 Condition of system on commissioning
N.2.7 Maintenance, inspection and cleaning
N.2.7.1 Frequency
N.2.7.2 Documentation
Cited references in this standard
Content history
[Available Superseded]
DR AS/NZS 3500.3:2020