WATER SERVICES ASSOCIATION of Australia
Polyethylene Pipeline Code WSA 01—2004 Third Edition Version 3.1
Originated as WSA 01—1998 Previous edition WSA 01—2001
WSA 01—2004-3.1
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ACKNOWLEDGMENTS The WSAA Board would like to express its appreciation to WSAA and PIPA Members for their contributions to the revision of this Code. DISCLAIMER WSAA Codes are published by the Water Services Association of Australia Inc. on the understanding that: The Water Services Association of Australia Inc. and individual contributors are not responsible for the results of any action taken on the basis of information in the Polyethylene Pipeline Code, nor any errors or omissions. The Water Services Association of Australia Inc. and individual contributors disclaim all and any liability to any person in respect of anything, and the consequences of anything, done or omitted to be done by a person in reliance upon the whole or any part of the Polyethylene Pipeline Code. PUBLICATION DETAILS Published jointly by: Water Services Association of Australia Inc. 469 Latrobe Street Melbourne Victoria 3000 Australia ISBN 1 8760 8864 8 COPYRIGHT Water Services Association of Australia will permit up to 10 percent of this Code to be copied for use exclusively in house by purchasers of this Code without payment of a royalty or giving advice to Water Services Association of Australia Inc. Water Services Association of Australia will also permit some or all of the Standard Drawings to be copied for use in contract documentation. © Copyright 2004 by WATER SERVICES ASSOCIATION of Australia Inc. All rights reserved.
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FOREWORD The experience and usage of PE for water and sewer pipes in Australia is increasing. HDPE sewer pipes have been installed since the 1980's and has a range of PE types for rehabilitation of both water mains and sewers. The use of PE 63 and PE 80B pipes for water service connections has been common since the 1990's. PE pipes and fittings are increasingly being used for a range of new water supply and sewerage systems, including recycled water and vacuum and pressure sewerage. Consideration is also being given to taking advantage of the weldability of PE and using it to construct fully welded gravity reticulation sewer systems, thereby limiting the likelihood of infiltration. The first edition of the Polyethylene Code was based on a document developed by Water Industry Technical Standards (WITS) with the assistance of R.J. LeHunt for use by the Melbourne retail Water Agencies, and included the experience and results of an extensive installation trial conducted by Sydney Water, together with the knowledge and experience of other Water Agencies, especially South Australia Water. The second edition of the Code introduced procedures for testing non-pressure pipelines and guidelines for vacuum sewers, as well as extensive revisions of testing and commissioning of pressure pipelines and other changes resulting from standards development and experience with manufacturing, design and installation, testing and commissioning of PE pipelines. This third edition of the Code continues to build on the experience and confidence of the urban water industry with use of PE pipelines. Revisions include: (a)
requirements for recycled water mains included e.g. colour, colour coding, storage, pressure class etc;
(b)
requirements for pressure and vacuum sewers included e.g. pressure class, clearances;
(c)
fitting design factors;
(d)
amendments to jointing requirements;
(e)
a completely revised general test procedures for pressure applications;
(f)
comments on use of repair clamps;
(g)
advice and limitations for squeeze-off;
(h)
new stiffness class requirement for non-pressure applications;
(i)
additional option for internal colour of non-pressure pipes;
(j)
limitations on use of coils for gravity sewers;
(k)
reference to new relining pipe standards;
(l)
new prerequisites for training; and
(m)
other editorial changes.
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CONTENTS Page ACKNOWLEDGMENTS ............................................................................................... 2 DISCLAIMER ............................................................................................................... 2 PUBLICATION DETAILS .............................................................................................. 2 COPYRIGHT ................................................................................................................ 2 FOREWORD
........................................................................................................ 3
1 INTRODUCTION ....................................................................................................... 7 1.1 BACKGROUND ...................................................................................................... 7 1.2 PURPOSE .............................................................................................................. 7 1.3 SCOPE................................................................................................................... 7 1.4 REFERENCED DOCUMENTS ............................................................................... 8 1.5 FURTHER READING ........................................................................................... 10 1.6 DEFINITIONS....................................................................................................... 10 1.6.1 Squeeze-off .................................................................................................. 10 1.6.2 Purple ........................................................................................................... 10 1.7 ABBREVIATIONS................................................................................................. 10 2 PRESSURE PIPELINES.......................................................................................... 12 2.1 GENERAL ............................................................................................................ 12 2.2 COMPOUND DESIGNATION ............................................................................... 12 2.3 PIPE SIZES .......................................................................................................... 12 2.4 EQUIVALENT PIPE SIZES................................................................................... 12 2.5 PRESSURE CLASS ............................................................................................. 12 2.6 PIPELINE IDENTIFICATION ................................................................................ 15 2.6.1 Pipes............................................................................................................. 15 2.6.2 Pipe colour coding ........................................................................................ 15 2.6.3 Colour compounds........................................................................................ 15 2.6.4 Striping ......................................................................................................... 15 2.6.5 Buried appurtenances ................................................................................... 15 2.6.6 Surface fittings .............................................................................................. 16 2.6.7 Above-ground pipelines ................................................................................ 16 2.7 STORAGE ............................................................................................................ 16 2.8 DELIVERY INSPECTION ..................................................................................... 16 2.9 STANDARD LENGTHS ........................................................................................ 16 2.10 PIPELINE DESIGN............................................................................................. 17 2.10.1 System life .................................................................................................. 17 2.10.2 Structural .................................................................................................... 17 2.10.3 Surge and fatigue........................................................................................ 17 2.10.4 Fitting design factors................................................................................... 18 2.10.5 Pressure pipe design factors....................................................................... 19 2.10.6 Environment................................................................................................ 19 2.10.7 Crossings.................................................................................................... 19 2.10.8 Surface obstructions and clearances .......................................................... 21 2.10.9 Underground obstructions and services and clearances ............................. 21 2.11 INSTALLATION .................................................................................................. 24 2.11.1 Trenching and embedment ......................................................................... 24 2.11.2 Pipelaying ................................................................................................... 24 2.11.3 Jointing ....................................................................................................... 25 COPYRIGHT
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2.11.4 Pipeline anchorage ..................................................................................... 25 2.11.5 Tapping....................................................................................................... 25 2.12 WELD PRE-QUALIFICATION............................................................................. 26 2.12.1 Butt fusion................................................................................................... 26 2.12.2 Electrofusion ............................................................................................... 26 2.12.3 Quality plans ............................................................................................... 27 2.13 TESTING AND COMMISSIONING ..................................................................... 27 2.13.1 General ....................................................................................................... 27 2.13.2 Pre-Testing Procedures .............................................................................. 28 2.13.3 Test procedure selection............................................................................. 28 2.13.4 Basic pressure test (Visual) ........................................................................ 28 2.13.5 General pressure test (Technical) ............................................................... 29 2.13.6 Commissioning ........................................................................................... 30 2.14 MAINTENANCE.................................................................................................. 30 2.14.1 Post installation works ................................................................................ 30 2.14.2 Repairs ....................................................................................................... 30 2.14.3 Squeeze-off ................................................................................................ 31 2.15 ELECTRICAL SAFETY....................................................................................... 32 3 NON-PRESSURE PIPELINES................................................................................. 33 3.1 GENERAL ............................................................................................................ 33 3.2 COMPOUND DESIGNATION ............................................................................... 33 3.3 PIPELINE SIZES .................................................................................................. 33 3.4 STIFFNESS [SN] .................................................................................................. 33 3.5 COLOUR .............................................................................................................. 33 3.6 STORAGE ............................................................................................................ 33 3.7 STANDARD LENGTH........................................................................................... 33 3.8 FITTINGS ............................................................................................................. 34 3.9 PIPELINE DESIGN............................................................................................... 34 3.9.1 System Life ................................................................................................... 34 3.9.2 Structural ...................................................................................................... 35 3.9.3 Hydraulic....................................................................................................... 35 3.9.4 Environment.................................................................................................. 35 3.10 INSTALLATION .................................................................................................. 35 3.10.1 Trenching and embedment ......................................................................... 35 3.10.2 Pipelaying ................................................................................................... 35 3.10.3 Property connection sewers and maintenance shafts ................................. 35 3.10.4 Jointing ....................................................................................................... 36 3.10.5 Maintenance holes and maintenance shafts ............................................... 36 3.11 Weld PRE-QUALIFICATION............................................................................... 36 3.11.1 Butt fusion................................................................................................... 36 3.11.2 Electrofusion ............................................................................................... 36 3.12 Testing ............................................................................................................... 36 3.13 MAINTENANCE.................................................................................................. 37 3.13.1 Post installation connections....................................................................... 37 3.13.2 Repairs ....................................................................................................... 37 4 RELINING APPLICATIONS..................................................................................... 38 4.1 GENERAL ............................................................................................................ 38 4.2 MATERIALS ......................................................................................................... 38 4.3 PIPE 38 4.3.1 Nominal diameters ........................................................................................ 38 4.3.2 Length........................................................................................................... 38 4.3.3 Colour 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4.4 FITTINGS ............................................................................................................. 38 4.5 PIPELINE DESIGN............................................................................................... 39 4.6 INSTALLATION .................................................................................................... 39 4.6.1 General......................................................................................................... 39 4.6.2 Jointing ......................................................................................................... 39 4.6.3 Connections.................................................................................................. 39 4.7 RELINING TYPES ................................................................................................ 39 4.7.1 Sliplining ....................................................................................................... 39 4.7.2 Pipe cracking and moling .............................................................................. 40 4.7.3 Swagelining .................................................................................................. 40 4.8 TESTING.............................................................................................................. 40 5 PERSONNEL QUALIFICATIONS ............................................................................ 41 5.1 GENERAL ............................................................................................................ 41 5.2 WELDING............................................................................................................. 41 5.3 TRENCHLESS TECHNOLOGY ............................................................................ 42 APPENDIX A ...................................................................................................... 43 EQUIVALENT PIPE DIAMETERS .............................................................................. 43 APPENDIX B ...................................................................................................... 47 REFERENCES FOR USE BY DESIGNERS WHEN MANAGING THE RISK OF INSTALLATION, OPERATION AND MAINTENANCE OF PE PIPELINE SYSTEMS IN CONTAMINATED LAND............................................................................................. 47 APPENDIX C ...................................................................................................... 48 STANDARD DRAWINGS ........................................................................................... 48 C1 GENERAL............................................................................................................. 48 C2 LISTING OF STANDARD DRAWINGS ................................................................. 49
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1 INTRODUCTION 1.1 BACKGROUND ICI scientists discovered polyethylene (PE) in 1933 in the United Kingdom. Low density polyethylene (LDPE) was first produced and marketed in 1945, followed by high density polyethylene (HDPE) in 1955 and medium density polyethylene MDPE (PE 63, PE 80B and PE 80C) in 1971. In more recent times higher performing HDPE compounds have been added to the PE 80B range and a new compound of HDPE, PE 100, with strength properties significantly higher than normal HDPE, has been produced and marketed. PE 80B and PE 100 compounds are mainly used in the water industry. Pipes range in size from DN 25 to DN 1600 with applications that include submerged ocean outfalls, water reticulation, vacuum and pressure sewers, and pipelines to service properties. 1.2 PURPOSE The WSAA PE Code is intended to guide water industry practitioners towards best practice in the use of PE pipeline systems. Its adoption by the national water industry and referencing in contracts should provide benefits to the Water Agencies and the urban development industry in terms of product standardization, availability and price, installation methods and controls and as a basis for curricula development for training programs. The PE Code should be read in conjunction with other WSAA Codes such as WSA 02 Sewerage Code, WSA 03 Water Supply Code, WSA 04 Sewage Pumping Station Code and WSA 07 Vacuum Sewerage Code, all of which in turn reference the PE Code. The information outlined in this Code is progressively being incorporated into and referenced by other national standards, codes and specifications which address the design, construction, testing and commissioning, operation and maintenance of water and sewerage networks and the relevant products and test methods. This Code will also provide a focus for continuous improvement of best industry practice in the use of PE pipeline systems especially as more experience is gained through their wider adoption throughout the Australian and New Zealand Water Agencies. The Code provides a mixture of mandatory and informative statements. The mandatory requirements are a mixture of both prescriptive and performance requirements. Overall, the Code provides “deemed-to-comply” solutions to the planning, design and construction of pressure and non-pressure pipeline networks. The information and guidance (informative text) contained in the Code has been deliberately interspersed throughout the mandatory requirements to provide some context and enable better understanding of the mandatory requirements. Informative text has been italicised to enable clearer differentiation. However, it is emphasised that the exact approach taken to all aspects of a particular project is the decision of the Water Agency and Planners, Designers and Constructors involved in each project. This Code provides technical information to aid in that process. 1.3 SCOPE The Code consists of four main sections: Section 2 PRESSURE PIPELINES A general guide to water reticulation and sewage pressure mains focussing on PE pipeline selection, design, installation, testing, commissioning and maintenance, as well as advice on electrical safety.
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Section 3 NON-PRESSURE PIPELINES A general guide to gravity sewers focussing on PE pipeline selection, design, installation, testing and maintenance. Section 4 REHABILITATION USING POLYETHYLENE A general guide to PE relining systems. Section 5 PERSONAL QUALIFICATIONS Personal qualifications and training programs to ensure that personnel involved in the installation of PE pipe systems are competent. It includes the relevant units of competency of suitable training packages and certification requirements for personnel involved in the design, installation and maintenance of PE pipeline systems. Although it may not always be considered essential, it is preferred that design and operational staff undertake formal training as both safety and operational factors are paramount to the welding process. 1.4 REFERENCED DOCUMENTS The following documents are referred to in this Code: AS 1345
Identification of the contents of pipes, conduits and ducts
2033
Installation of polyethylene pipe systems
2700
Colour standards for general purposes
4087
Metallic flanges for waterworks purposes
4181
Stainless steel clamps for waterworks purposes
AS/NZS 1260
PVC pipes and fittings for drain, waste and vent applications
1477
PVC pipes and fittings for pressure applications
2280
Ductile iron pressure pipes and fittings
2566
Buried flexible pipelines
2566.1
Part 1:
Structural design of buried flexible pipe
2566.2
Part 2:
Installation of buried flexible pipe. (under preparation)
4129
Fittings for polyethylene (PE) pipes for pressure applications
4130
Polyethylene (PE) pipes for pressure applications
4131
Polyethylene (PE) compounds for pressure pipe and fittings
4441(Int)
Oriented PVC (PVC-O) pipes for pressure applications
4765(Int)
Modified PVC (PVC-M) pipes for pressure applications
4798(Int)
Polyethylene (PE) maintenance shafts
5065
Polyethylene (PE) and polypropylene (PP) pipes and fittings for drainage and sewerage purposes
ISO 9000
Quality management and quality assurance Standards
ISO 9000.1 Quality systems—Model for quality assurance in design, development, production, installation and servicing
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ASTM D 2321
Standard practice for underground installation of thermoplastic pipe for sewers and other gravity-flow applications
F 894
Polyethylene (PE) large diameter profile wall sewer and drain pipe
F 1417
Standard test method for installation acceptance of plastic gravity sewer lines using low-pressure air
BS EN 13566
Plastics piping systems for renovation of underground non-pressure drainage and sewerage networks
13566-1
Part 1: General
13566-2
Part 2: Lining with continuous pipes
13566-3
Part 3: Lining with close fit pipes
13566-4
Part 4: Lining with cured-in-place pipes
NZS 7702
Colour standards for general purposes
POP 004
Polyethylene Pipe Compounds
006
De-rating requirements for fittings
007
Steel backing flanges for use with polyethylene pipe (PE) flange adaptors
010A
Part 1 Polyethylene Pressure Pipes—Design for Dynamic Stresses
010B
Part 2 Fusion Fittings for use with Polyethylene Pressure Pipes— Design for Dynamic Stresses
ISO 13953
Polyethylene (PE) pipes and fittings—Determination of the tensile strength and failure mode of test pieces from a butt-fused joint
WIS 4-32-08
Specification for site fusion jointing of MDPE pipe and fittings
WSA 02
Sewerage Code of Australia
03
Water Supply Code of Australia
04
Sewage Pumping Station Code of Australia
07
Vacuum Sewerage Code of Australia
109
Water Industry Standard for Flange Gaskets and O rings
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1.5 FURTHER READING Manual for Polyethylene Pipe Systems for Water Supply Applications. Report No. FR 0386 July 1994 WRc plc. POLIplex Polyethylene Pipe Design Textbook, Iplex Pipelines Australia Pty Limited, 1997. Polyethylene Pipe & Fittings Technical Manual, Vinidex Pty. Limited, 1999. (CD Rom) Plastic Pipes for Water Supply and Sewage Disposal, Lars-Eric Janson, Borealis, Stockholm, 4th edition 2003. PPI Handbook of Polyethylene Piping – The Plastic Pipe Institute, 1825 Connecticut Ave., NW Suite 680 Washington, DC 20009 Ref:
Engineering Properties; Pipe and Fittings Manufacturing; Jointing Procedures; Underground Installation; Pipeline Rehabilitation by Sliplining; Above Ground Applications and other titles.
1.6 DEFINITIONS For the purpose of this Code the definitions given in WSA 02, WSA 03, WSA 04, WSA 07 and AS/NZS 3500.0 and those below shall apply. 1.6.1 Squeeze-off The closing down or isolating of PE pipelines by pinching or squeezing the walls of the pipe together. 1.6.2 Purple A colour defined in accordance with AS 2700 (NZS 7702) as being no darker than P24 Jacaranda or P12 Purple and no lighter than P23 Lilac 1.7 ABBREVIATIONS The following abbreviations apply in this Code: °
degrees
ABS
acrylonitrile butadiene styrene
AC
asbestos cement
AS
Australian Standard
ASTM
American Society for Testing and Materials
CI
cast iron
CICL
cast iron cement mortar lined
DI
ductile iron
DICL
ductile iron cement mortar lined
DIN
Deutsche Norm (German Institute for Standardisation)
DN
nominal size, in millimetres
EN
European Norm COPYRIGHT
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GRP
glass reinforced polyester
HDPE
high density polyethylene
ID
internal diameter, in millimetres
ISO
International Organisation for Standardization
LDPE
low density polyethylene
m
metres
mm
millimetres
MAOP
maximum allowable operating pressure
MDPE
medium density polyethylene
MH
maintenance hole
MS
maintenance shaft
NZS
New Zealand Standard
PE
polyethylene
PIPA
Plastics Pipeline Industry Association of Australia
PPI
Plastics Pipe Institute
PN
nominal pressure, in megapascals x 10
prEN
draft European Norm
PVC
polyvinyl chloride
PVC-U
unplasticised polyvinyl chloride
QA
quality assurance
RC
reinforced concrete
SDR
standard dimension ratio
SN
nominal ring stiffness
UPVC
unplasticised polyvinyl chloride
VC
vitrified clay
WIS
Water Industry Specification (UK)
WRc
Water Research Centre (UK)
WSAA
Water Services Association of Australia
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2 PRESSURE PIPELINES 2.1 GENERAL Pipes and fittings shall comply with AS/NZS 4130 and AS/NZS 4129, respectively. 2.2 COMPOUND DESIGNATION PE 80B or PE 100 compounds to AS/NZS 4131 shall be used for all pressure pipes (Refer to Table 2.1). 2.3 PIPE SIZES Unless otherwise specified, pipe sizes (Refer to Table 2.1) shall be as follows: (a)
For potable water and recycled water mains, sizes DN 90, 110, 125, 160, 180, 250, 280, 315, 355, 450 and larger sizes as listed in AS/NZS 4130.
(b)
For recycled water mains in cul-de-sacs, sizes DN 50 and DN 63. It is now a requirement that looped mains be provided for potable water in cul-desacs to reduce the likelihood of water quality complaints (Refer to Figure 4.3 of WSA 03 .
(c)
For property potable water and recycled water services, sizes DN 25, 32, 40 and 50.
(d)
For sewer pressure mains, sizes DN 40 and larger as listed in AS/NZS 4130.
(e)
For vacuum sewers, sizes DN 110, 160, 225 and 315; for service connections DN 90 and for sensor pipes DN 63.
2.4 EQUIVALENT PIPE SIZES PE pipe is specified by its outside diameter in accordance with international standards (ISO). Equivalent PE pipe sizes for commonly specified pressure pipes shall be adopted as listed in Table 2.1 and Appendix A. These equivalent sizes have been chosen from the sizes available in the material and pressure class such that they have an equivalent internal diameter that satisfies hydraulic requirements. There are several PE pipe sizes available that have no equivalent in Table 2.1 (for example DN 110 and 160). These sizes may also be applicable to recycled water, sewer pressure mains and rehabilitation applications. 2.5 PRESSURE CLASS Pipes and fittings shall be: (a)
PN 10 or PN 12.5 or PN 16 (Refer Tables 2.1 and 2.3) for water mains;
(b)
PN 12.5 or PN 16 for pressure sewers; and
(c)
PN 12.5 for vacuum sewers.
The pressure class for pipes and fittings based upon designated risk factors shall be determined in accordance with Clause 2.10.3 and AS/NZS 4130. Lower pressure classes may be used for individually designed installations such as sewer pressure mains, low-pressure areas and in rehabilitation applications. For PN 16 installations, PE 100 provides the benefits of larger bore and consequently higher flow rates than for PE 80B of the same pipe pressure class.
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TABLE 2.1 PIPELINE DESIGNATION COMMONLY SPECIFIED WATER PIPE MATERIALS AND SIZES
PERMISSIBLE EQUIVALENT PE PIPE SIZE, PRESSURE CLASS AND COMPOUND TYPE
PERMISSIBLE PE JOINT SYSTEMS
Material Copper Type B
DN
PVC-PN12/16
Mean ID mm
DN
Mean ID mm
PN
Compound Type
Electrofusion
Butt Fusion
Compression
Bolted
PE
Mechanical
Flange
Fittings
adaptors
DICL-K9 20
17
25
21-22 20-21 19-20
10 12.5 16
PE 80B/100
Yes
No
Yes
25
23
32
27-28 26-27 24-26
10 12.5 16
PE 80B/100
Yes
No
Yes
32
29
40
34-35 32-34 30-33
10 12.5 16
PE 80B/100
Yes
No
Yes
40
36
50
42-44 41-42 39-41
10 12.5 16
PE 80B/100
Yes
No
Yes
50
48
63
53-56 51-53 48-51
10 12.5 16
PE 80B/100
Yes
No
Yes
Copper
Copper
Copper
Copper
Copper
(continued)
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Material Copper Type B
DN
PVC-PN12/16
Mean ID mm
DN
Mean ID mm
PN
Compound Type
Electrofusion
Butt Fusion
Compression
Bolted
PE
Mechanical
Flange
Fittings
adaptors
DICL-K9 Copper
65
61
90
76-79 73-76 69-73
10 12.5 16
PE 80B/100
Yes
No
Yes
Copper/DICL
80
73/72
90
76-79 73-76 69-73
10 12.5 16
PE 80B/100
Yes
No
Yes
110
94-97 90-94 85-90
10 12.5 16
PE 80B/100
Yes
Yes
125
106-110 101-106 96-101
10 12.5 16
PE 80B/100
Yes
Yes
10 12.5 16
PE 80B/100
Yes
Yes
Yes
Yes
PVC/DICL
100
102/104/ 98
160
PVC/DICL
150
143/152/ 153
136141 130-136 123-130
180
153-158 146-153 138-146
10 12.5 16
PE 80B/100
10 12.5 16
PE 80B/100
Yes
Yes
PVC/DICL
200
203/202/ 204
250
212-220 203-212 192-203
PVC/DICL
225
226/226/ 229
280
238-246 228-238 216-228
10 12.5 16
PE 80B/100
Yes
Yes
PVC/DICL
250
253/249/ 256
315
268-277 256-268 242-256
10 12.5 16
PE 80B/100
Yes
Yes
PVC/DICL
300
284/301/ 313
355
302-311 289-302 273-289
10 12.5 16
PE 80B/100
Yes
Yes
PVC/DICL
375
361/371/ 391
450
382-396 366-382 346-366
10 12.5 16
PE 80B/100
Yes
Yes
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Not acceptable except for emergency maintenance and special situations
Acceptable only for connection to valves, hydrant tees, hydrant bends and flanged connections to other pipe systems or emergency maintenance situations.
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2.6 PIPELINE IDENTIFICATION 2.6.1 Pipes There is no international or Australian/New Zealand Standard standardised colour coding for the identification of buried pipelines. For buried pipelines, “blue” has become the default colour for potable water (e.g. refer to AS/NZS 4130), although for above-ground pipelines “blue” indicates compressed air. For recycled water, the leading jurisdiction in the use of recycled water is California where recycled water was first used in the 1890’s. The current State of California Water Recycling Criteria (adopted in December 2000) requires the use of purple pipe, which has been their practice for over 15 years. The Department of Health, NSW, in its Guidelines for Urban and Residential Use of Reclaimed Water subsequently adopted the colour “deep purple” for piping containing recycled water. 2.6.2 Pipe colour coding The colour coding for identification of PE pipes for different applications shall be as follows: (a)
Black pipe with blue stripes for potable water applications, except in recycled water areas where blue or blue jacketed pipe is required for property potable water services.
(b)
Black pipe for pressure sewerage applications. If condition assessment using CCTV inspection is anticipated, then black pipes with a co-extruded internal white or natural liner should be used.
(c)
Black pipe with purple stripes for recycled water reticulation mains and purple jacketed pipe for recycled water property service pipes.
2.6.3 Colour compounds Blue compounds shall comply with AS/NZS 4130. Purple compounds shall contain sufficient quantity of pigment such that the colour of pipes, stripes on pipe and pipe jackets manufactured from these compounds shall be as follows: (a)
no darker than P24 Jacaranda or P12 Purple, in accordance with AS 2700 (NZS 7702).
(b)
no lighter than P23 Lilac, in accordance with AS 2700 (NZS 7702).
Compliance with the compound colour requirements may be evaluated by visual examination against the relevant colour reference of AS 2700 (NZS 7702). In the case of a dispute, the batch of pipes will need to have its colour ordinates measured. These ordinates should be within the ordinates for the maximum and minimum colours of AS 2700 (NZS 7702) given, using the same colour measuring technique. 2.6.4 Striping The blue or purple stripes shall be placed equidistant around the circumference of the pipe. The stripes shall have a minimum width of 3 mm and shall be applied as follows: (a)
A minimum of four (4) stripes for DN 90 pipe and smaller;
(b)
A minimum of six (6) stripes for DN 110 pipe to DN 315 pipe;
(c)
A minimum of eight (8) stripes for pipe larger than DN 315.
2.6.5 Buried appurtenances The colour coding of buried fittings, valves, hydrants, etc is not considered critical for pipeline identification. Pipe fittings are generally black.
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2.6.6 Surface fittings For surface fittings on buried pressure pipelines the following markings shall be adopted as appropriate to the size of the visible surface of the fitting as installed: (a)
for potable water refer to WSA 03;
(b)
for recycled water, the letters “RW” or words “recycled water”;
(c)
for vacuum sewers, the letters “VS” or words “vacuum sewer”; and
(d)
for pressure sewers, the letters “PS” or words “pressure sewer”.
2.6.7 Above-ground pipelines The identification of contents of above ground pipelines shall be in accordance with AS 1345. 2.7 STORAGE Pipe and fittings shall be stored as follows: (a)
All pipe shall be stacked in a manner to minimise pipe ovalisation.
(b)
For black pipe with blue or purple stripes and for blue or purple jacketed pipe outside storage shall be limited to a maximum of two years from the date of pipe manufacture prior to installation.
(c)
Fittings, and sealing materials shall be left in the original sealed cartons until used and stored in secure areas away from direct sunlight. Fittings conforming to AS/NZS 4129 have a storage life at least equal to black PE pipe.
For solid black pipe outside storage can be unlimited. 2.8 DELIVERY INSPECTION PE is a tough resilient material that is relatively light and easy to handle although, like all plastics, it is prone to damage through scoring by sharp objects. Careful packaging and handling is required for successful delivery of pipes and fittings to site, especially when transported over long distances. All pipes and fittings shall be inspected for damage at the time of delivery. The maximum allowable depth of scoring or abrasion of external surfaces shall be 10% of the wall thickness or 5 mm, whichever is the less. Unless otherwise agreed, fittings shall be supplied in sealed separate bags or cartons together with any associated small items such as bolts, nuts, washers and gaskets. The ovality requirements for PE pipe only apply at the time of manufacture and before coiling. Ovality requirements are not be applicable to pipe of SDR >17.6. Kinked or crushed pipe shall be rejected. Coiled PE pipe when removed from the coil or drum will be oval and curved. The extent of ovality and curvature will depend upon the ambient temperature, SDR, pipe diameter, coil diameter and compound type. Although both ovality and curvature may reduce naturally with time, special equipment is available to facilitate handling and jointing. Coiled pipe is usually limited to a maximum of DN 125. 2.9 STANDARD LENGTHS Unless otherwise specified, the industry standard lengths shall be: (a)
For coils, nominal lengths of 50 or 100 m.
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For straight lengths, nominal 12 m.
Other lengths (6, 15 and 20 m) may also be supplied to order. Check with manufacturers for their nominated standard lengths. Check that longer lengths are transportable to site and able to be handled on site. 2.10 PIPELINE DESIGN 2.10.1 System life Selection of allowable stress is based on long term pressure testing in the laboratory and regression analysis applied to the data obtained. The 50 year point is arbitrarily chosen for this basis, as for all thermoplastics pipes. A factor is applied to the 50 year point in order to provide the design stress. It shall not be taken that either: (a)
the pipes weaken with time; or
(b)
the predicted life is 50 years.
System life is dependent on many factors. If the design stress were used in relation to the regression curve, predicted pipe life would be indefinite, not 50 years. As with other materials, the life is dependent on manufacture, transport, handling, installation, operation, protection from third party damage and other external factors. Provided that PE pipeline system components are appraised and supplied to nominated industry standards under third-party product certification systems, and provided pipelines are designed and constructed correctly, then the likelihood of failure is minimised. For correctly manufactured and installed systems, the actual life cannot be predicted, but can logically be expected to be well in excess of 100 years before major rehabilitation is required. If a system life is to be assigned beyond 100 years, it shall be based on the likelihood of failure arising from the above factors, not the pipe regression curve. Pipe strength has been shown not to decrease with time—in fact, it increases slightly. "Instantaneous" burst pressure after a period in service will be at least equal to that of new pipe. 2.10.2 Structural Pipeline structural design shall be in accordance with AS/NZS 2566.1. In most normal installations where the pipe is installed in accordance with Code Standard Drawings appropriate to the application, a structural design is not required. However, the Designer should evaluate the possibility of negative head collapse. 2.10.3 Surge and fatigue For non-pumped pipelines, where the system pressure varies only as a result of diurnal pressure variations, the maximum design pressure shall not exceed the pressure rating of the pipe and fittings. For pumped pipelines, a surge analysis shall be carried out and the maximum surge pressure under normal operating conditions shall not exceed the pressure rating of the pipe and fittings. Surge analysis of pipeline networks is complex and subject to ongoing research. Further requirements for design for surge and fatigue are outlined in the appropriate Codes e.g. WSA 03 and WSA 04. The pipe manufacturer may also be contacted for advice. However, as a guide, the maximum surge pressure can be estimated by multiplying the MAOP by a
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surge factor of 1.25. No adjustment for operating temperature need be applied for surge and fatigue design. For fatigue loading situations, the maximum pressure reached in the repetitive cycle shall not exceed the pressure rating of the pipe and fittings. Fatigue re-rating factors for PE 80B and PE 100 pipes and fittings shall be as shown in Table 2.2. To select the appropriate pipe and fittings class for fatigue loading, the following procedure shall be adopted: (a)
Estimate the likely pressure cycle amplitude, i.e. the maximum pressure minus the minimum pressure.
(b)
Estimate the frequency or number of cycles per day (or week or month etc) that are expected to occur.
(c)
Determine the required life and calculate the total number of cycles that will occur in the design lifetime e.g. 100 years.
(d)
From Table 2.2 determine the fatigue load factor for the number of cycles.
(e)
Divide the pressure amplitude by the fatigue load factor to obtain the equivalent operating pressure.
(f)
Use the equivalent operating pressure to select the class of pipe and fitting required. TABLE 2.2 FATIGUE RE-RATING FACTORS FOR PE 80B, AND PE 100 PIPES AND FUSION FITTINGS Total Cycles
Factors Load Factors 13
Approximate number of cycles per day for 100 year life
Pipes
Fusion fittings
PE 80B and PE 100
PE 80B and PE 100
1.00
12
1.00
12
36,500
1
100,000
3
1.00
1.00
300,000
8
1.00
1.00
500,000
14
0.95
0.95
1,000,000
27
0.88
0.88
5,000,000
137
0.74
0.74
10,000,000
274
0.68
-
50,000,000
1,370
0.57
-
NOTES: 1
Maximum allowable factor for fatigue loading pressure cycles.
2
Reproduced from Table 1 of POP010A and Table 1 of POP010B. For further information refer to PIPA Industry Guidelines
2.10.4 Fitting design factors Where fabricated sweep bends, tees and other fittings for use with PE pipe to AS/NZS 4130 are proposed, the fittings shall be evaluated. Unless performance and test data is provided to support alternative values, weld factors and geometry de-rating factors as outlined in POP006 shall be used to re-rate the fitting. This aspect is particularly important where larger diameter fittings e.g. >DN 180 are required to be fabricated from pipe. Smaller diameter moulded and electrofusion fittings generally are designed to account for geometry factors and further re-rating is not required.
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2.10.5 Pressure pipe design factors The design factor used to determine the nominal pressure rating, PN, for Series 1 PE pipes is 1.25. For calculation of MAOP for Series 1 pipes with increased design factors refer to AS/NZS 4130. Unless otherwise agreed, design factors for pressure applications shall be in accordance with Table 2.3. Based on installation conditions, the maximum operating pressure shall be multiplied by the relevant factors to produce a risk considered MAOP for pipe class selection. As the temperature to which the PE pipe is exposed increases above the reference temperature (20°C) the long-term hydrostatic strength decreases. Consequently, the pipe PN rating shall be factored to suit the operating temperature as described in Table 2.3. The design factors nominated are intended to take into account uncertainty and risk factors associated with pipeline installation. Table 2.3 is not intended to cover every conceivable situation. Where there is doubt, the designer should contact the Water Agency for advice. 2.10.6 Environment PE is resistant to many chemicals, but is susceptible to chemical attack and/or permeation by petroleum products and certain solvents (For further information refer to AS 2033 Appendix A, Iplex Pipelines POLIplex Textbook and Vinidex Polyethylene Manual. Where pressure pipelines are to be installed in suspected contaminated ground, specific soil sampling shall take place to identify reagents in the ground and surrounding groundwaters. Where contaminants deemed to be damaging or capable of permeating PE are identified, the risk of using PE pipe systems shall be carefully evaluated. Where PE pipe is specified, only fully welded PE systems shall be used. Where leaching of contaminants into the pipe alignment may re-occur the PE pipe shall be contained within an impervious sealed conduit. The references listed in Appendix B may be used by design consultants and constructors to manage the risk of installation, operation and maintenance with PE pipeline systems in contaminated land. The properties of PE make such pipelines particularly suitable for areas subject to ground movement due to expansive clays, seismic forces, mining subsidence or compaction of filled sites. At low temperatures PE maintains its good characteristics such as impact strength such that in many parts of the world that experience below freezing temperatures (below –18°C) PE is the preferred pipe material. 2.10.7 Crossings Pressure main crossings of roads, railway lines, creeks and underground services shall, as far as practicable, be at right angles. Mains should be located and designed to minimise maintenance and crossing restoration costs.
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TABLE 2.3 PRESSURE PIPE DESIGN FACTORS Condition Fluid
Installation Water Domestic sewage Industrial sewage
Soil, Fluid or Pipe Temperature Average t°C
−20 35
Location Based on minimum depth of cover specified in AS/NZS 2566.1
Installation Method
Factor
Index
1.0
f0
1.0
1
1.0 Refer manufacturer 0.6 1.0 1.1 1.25 Refer manufacturer
f1
Open field
1.0
f2
Minor country road shoulder
1.0
Major country road shoulder
1.0
Minor country road—under pavement
1.1
Major country road—under pavement
1.2
Residential—paved and unpaved nature strip (footpath)
1.0
Residential roadway—under pavement
1.1
Major urban road—under pavement
1.2
Commercial/Industrial paved and unpaved nature strip (footpath)
1.1
Commercial/Industrial roadway—under pavement
1.2
Central Business District
1.4
Private land—easement
1.0
Above ground
1.0
Submarine crossings
1.4
Standard trenching
1.0
Plough-in
1.1
Slip line with back grouting
1.0
Slip line without back grouting
1.2
Pipe cracking - with liner pipe in-situ
1.0
Pipe cracking - with liner pipe removed
1.2
f3
NOTES: 1
Where contaminants capable of damaging PE compounds are identified the risk of using a PE system shall be carefully evaluated.
2
Choose only one factor from each condition;
3
This Table applies to PE 80B and PE 100 pipe with a life expectancy of >100 years;
4
Pumped installations require further design consideration, refer to PIPA Industry Guidelines;
5
Work examples are also shown in AS/NZS 4130; and
6
Design Factor F = f 0 x f 1 x f 2 x f 3
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2.10.8 Surface obstructions and clearances Surface obstructions shall be located during the initial survey and inspection of the site and through enquiries to local government and other service utilities. Dimensions of obstructions at the surface might be different from their underground dimensions. For pressure mains located close to existing structures such as foundations for brick walls and buildings, the ongoing stability of the structure needs to be maintained. The location shall be clear of the “zone of influence” of the structure foundations to ensure that the stability of the structure is maintained and that excessive loads are not imposed on the pipeline. Use Table 2.4, as a guide for minimum clearances. TABLE 2.4 MINIMUM CLEARANCE FROM STRUCTURES Pipe diameter DN
Clearance to wall or building mm
<100
600
100 – 150
1000
200 – 300
1500
>375
2000
2.10.9 Underground obstructions and services and clearances Underground services and other obstructions such as power conduits/cables, gas mains, drains, telecommunication conduits/cables, oil/petrochemical pipelines and the underground portions of surface obstructions (tree roots, pits, etc) may affect the proposed alignment of the pipeline both in plan and in level. Where the pipeline crosses other services, the depth of those services shall be determined. Services outside the project area may also affect the pipeline layout. Details of large diameter sewers, drains and water mains shall be obtained from the relevant Water Agency. Excavation may be required to determine the exact location and depth of all underground obstructions. Agreement on clearances shall be reached with the relevant service owner before the design is adopted. Dial Before You Dig, a ‘One Call System’ to locate underground utility services, operates in all states and territories. The number to call nation-wide is 1100. Nevertheless, hand excavation (pot-holing) is recommended to determine the exact location and depth of underground obstructions during design and again immediately prior to excavation. When using trenchless technology installation, clearances of pipelines from other utility services shall not be less than those clearances required for pipelines laid in an open trench. Clearance from other service utility assets shall be maximised wherever practicable. Minimum vertical and horizontal clearances are shown in Tables 2.5, 2.6 and 2.7. Services shall cross at 90° if possible, but not less than 45°. Assets owned by other service utilities, existing and proposed, shall be considered when selecting the pipeline location. Alignment of all service utility assets shall be shown on the Design Drawings. Other utility assets that may be hazardous and require additional care shall be noted on the Design Drawings. COPYRIGHT
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TABLE 2.5 1
CLEARANCES BETWEEN WATER MAINS AND UNDERGROUND SERVICES Minimum horizontal clearance Utility (Existing service)
mm
Minimum vertical clearance
New main size
mm
2
≤DN 200
>DN 200
Water mains >DN 375
600
600
500
Water mains ≤DN 375
300
600
150
Gas mains
300
600
150 - low pressure gas mains
3
3
300 - high pressure gas mains 3
Telecommunication conduits and cables
300
Electricity conduits and cables
500
Drains
300
Sewers
1000 /600
1000 /600
Kerbs
150
600
3
5
600
150
1000
225
600
150
5
6
500
4 4
150 (where possible)
NOTES: 1
Includes potable and recycled water mains
2
Vertical clearances apply when water mains cross one another and other utility services, except in the case of sewers when a vertical separation shall always be maintained, even when the main and sewer are parallel. The main should always be located above the sewer to minimise the possibility of backflow contamination in the event of a main break.
3
Clearances can be further reduced to 150 mm for distances up to 2 m when passing installations such as poles, pits and small structures, providing the structure is not destabilised in the process.
4
Water mains should always cross over sewers and stormwater drains. For cases where there is no alternative and the main must cross under the sewer, construction shall be in accordance with Standard Drawing WAT–1211.
5
When the sewer is at the minimum vertical clearance below the water main (500 mm), maintain a minimum horizontal clearance of 1000 mm. This minimum horizontal clearance can be progressively reduced to 600 mm as the vertical clearance is increased to 750 mm.
6
Clearance from kerbs shall be measured from the nearest point of the kerb. For water mains
≤ DN 375 clearances from kerbs can be progressively reduced until the minimum of 150 mm is reached for mains ≤ DN 200.
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TABLE 2.6 CLEARANCES BETWEEN PRESSURE SEWERS AND UNDERGROUND SERVICES Minimum horizontal clearance Utility (Existing service)
Water mains Gas mains
mm
Minimum vertical clearance
Pipeline size
mm
≤DN 200
>DN 200
1000
1000
500
600
150
300
2 2
Telecommunication conduits and cables
300
Electricity conduits and cables
500
Drains
300
Sewers
300
Kerbs
150
600
1
150 - low pressure gas mains 300 - high pressure gas mains
2 2
1000
225
600
150
600
500
600
3
3 3
150 (where possible)
NOTES: 1
Vertical clearances apply when pipelines cross other utility services, except in the case of water mains when a vertical separation shall always be maintained, even when the pressure sewer and water main are parallel. The pressure sewer should always be located below the water main to minimise the possibility of backflow contamination in the event of a pressure main break.
2
Clearances can be further reduced to 150 mm for distances up to 2 m when passing installations such as poles, pits and small structures, providing the structure is not destabilised in the process.
3
Clearance from kerbs shall be measured from the nearest point of the kerb. For pressure sewers
≤ DN 375 clearances from kerbs can be progressively reduced until the minimum of 150 mm is reached for mains ≤ DN 200.
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TABLE 2.7 CLEARANCES BETWEEN VACUUM SEWERS AND UNDERGROUND SERVICES Minimum horizontal clearance Utility (Existing service)
mm
Minimum vertical clearance
Pipeline size
mm
≤DN 200 Water mains
300
2
1
>DN 200 600
150 for vacuum sewers 500 for pressure mains
Gas mains
300
2
600
150 - low pressure gas mains 300 - high pressure gas mains
2
Telecommunication conduits and cables
300
Electricity conduits and cables
500
Drains
300
Sewers
300
Kerbs
150
2 2
600
150
1000
225
600
150
600
500
600
3
3 3
150 (where possible)
NOTES: 1
Vertical clearances apply when pipelines cross other utility services, except in the case of water mains when a vertical separation shall always be maintained, even when the pressure main and water main are parallel. The pressure main should always be located below the water main to minimise the possibility of backflow contamination in the event of a pressure main break.
2
Clearances can be further reduced to 150 mm for distances up to 2 m when passing installations such as poles, pits and small structures, providing the structure is not destabilised in the process.
3
Clearance from kerbs shall be measured from the nearest point of the kerb. For pressure mains
≤ DN 375 clearances from kerbs can be progressively reduced until the minimum of 150 mm is reached for mains ≤ DN 200.
2.11 INSTALLATION Installation of PE pipelines shall be in accordance with AS/NZS 2566.2. Typical installation details for PE pipelines are shown in Standard Drawings WAT–1102, WAT–1104, WAT–1105 of WSA 03. 2.11.1 Trenching and embedment The trench and embedment requirements for plastics pipes outlined in Standard Drawing WAT–1201 of WSA 03 shall apply. 2.11.2 Pipelaying PE has a high coefficient of thermal expansion. PE pipes shall be installed to allow for the difference in ambient temperature and the transported water or the in-ground temperature. To minimize residual stress in the pipe, where practicable, the pipe shall be allowed to stabilise at approximately the service temperature before final connection and back filling. Detectable tape shall be installed in the trench along the top of the pipe unless otherwise agreed by the Water Agency. PE pipe located directly under roads, tram or rail lines shall be installed in accordance with the asset owner’s requirements. Only fully welded joints, or single length pipe shall be used. COPYRIGHT
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'Plough in' type installations should be considered on their merits with respect to the affects of 'spring back', ground conditions suited to PE pipe embedment, obstructions and environmental considerations. 2.11.3 Jointing For pipe sizes up to and including DN 90, joints shall be the compression or electrofusion type complying with AS/NZS 4129. For new installations of pipe in diameters greater than DN 90, butt welding or electrofusion coupling jointing shall be used. Only trained and certified welders shall perform weld jointing of pipelines (Refer to Section 4). Spigot and socket fusion welding shall not be permitted. Electrofusion systems shall permit manual operation and be limited to the long bodied, 4.0/4.7 mm diameter single pin connections conforming to the requirements of AS/NZS 4129. Butt welding between PE 80B and PE 100 or the same SDR shall be permitted. Pipes of different SDRs shall only be joined using electrofusion fittings. Flanged fittings shall comply with AS/NZS 4129. Only full-face flanges complying with the bolting details of AS 4087, Figure B2 shall be permitted for hydrant installations. A typical arrangement for hydrant installation is shown on Standard Drawing WAT–1409. Sealing gaskets complying with WSA 109 shall be used in all flanged joints. Where PE pipe is to be connected to other pipe materials, valves or other fittings or where there is a requirement for future disassembly, a flange adaptor, or a PE stub flange or other approved end-thrust resistant fittings shall be used. The backing plate or backing flange, bolts, nuts and washers shall be manufactured from Grade 316 stainless steel. Shouldered end joints of the split metal housing type used in mining applications shall not be permitted. Mechanical compression joint fittings larger than DN 90 and complying with AS/NZS 4129 may be used for temporary services and special site conditions where it is impractical to use a welded joint. Where PE stub flanges are used in conjunction with a metallic flange, only raised faced flange faces shall be used (Refer to WAT–1313 of WSA 03). 2.11.4 Pipeline anchorage Where the jointing system does not have sufficient axial strength capability, anchorage at bends, tees, reducers and dead ends shall be provided to resist the forces in accordance with WSA 03. Installation techniques for anchor blocks shall be in accordance with the relevant standard drawings of WSA 03. Electrofusion joints, butt weld joints and compression fittings that comply with AS/NZS 4129 can develop the full axial strength of the pipe and in buried applications do not require thrust blocks to resist internal pressure forces at bends, tees, reducers, offsets, dead ends, etc. 2.11.5 Tapping Service tapping sizes shall be DN 25, DN 32, DN 40 and DN 50. Service isolating valves at the main (ball valves) for DN 25 and DN 32 shall not be installed for main sizes DN 180 and less unless otherwise required by the Water Agency. Electrofusion welded tapping saddles shall be used at all times with new installations of PE pipe. Where the use of electrofusion tapping saddles is determined impractical by the project manager, mechanical tapping saddles complying with AS/NZS 4129 may be used for:
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(a)
tapping PE minor mains (
(b)
rehabilitation installations using PE in sizes up to and including DN 180; and
(c)
connections to existing PE mains and above-ground PE mains.
Where mechanical tapping saddles are used, a minimum spacing of 500 mm between tappings shall be maintained and tapping shall not be performed closer than 500 mm from the termination of the PE pipeline. Tapping of curved PE pipe shall take place only at the top of the pipe to minimise stress around the tapping hole. Where dry tapping is performed, a plug cutter shall be used, and all swarf removed. Under pressure tapping shall be permitted only with systems that utilise plug cutters that retain the PE pipe wall plug within the cutter. Where welded tapping systems are used, the assembly shall be allowed to fully cool naturally before tapping. Tapping of straight pipe sections may take place on the side of the pipe. 2.12 WELD PRE-QUALIFICATION 2.12.1 Butt fusion Before factory and field butt welding, pre-qualification of the welding procedure shall be obtained. The following information shall be submitted to the Water Agency or project manager for acceptance: (a)
all details of the works for approval prior to commencing work;
(b)
the welding procedures to be used;
(c)
the welding equipment to be used;
(d)
the name and certification details of the certified welder;
(e)
test results of the pilot welds to confirm the test specification requirements;
A pilot weld for each welding machine, pipe diameter, wall thickness and material type with a record of the parameter values for each weld shall be made. Pilot welds shall be tested in accordance with ISO 13953. To be accepted, the weld under test shall fail in a ductile mode. The test pieces shall be retained for examination by the project manager. 2.12.2 Electrofusion Before factory and field electrofusion welding, including tapping saddles/bands, prequalification of the welding procedure shall be obtained. The following information shall be submitted to the Water Agency or project manager for acceptance: (a)
all details of the works for approval prior to commencing work;
(b)
the welding procedures to be used including the following; (i)
standard fusion time;
(ii)
standard cooling time;
(iii)
welding equipment to be used, including control box details;
(iv)
surface preparation of pipe surfaces to be welded and clamping arrangements;
(v)
the name and certification details of the certified welder;
(vi)
a pilot weld for each welding machine, pipe diameter, wall thickness and material type with a record of the parameter values for each weld; and
(vii) test results of the pilot welds to confirm the test specification requirements.
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The pilot welds shall be tested in accordance with Clause 3.6.4 of AS/NZS 4129. 2.12.3 Quality plans A quality plan shall be prepared to demonstrate ongoing quality of welds and submitted to the project manager. The quality plan shall address the maintenance, servicing and calibration of equipment; inspection and testing, comprising inspection of goods received and used on site, surface preparation of pipe surfaces to be welded, clamping arrangements, final inspection and testing, and shall include a sampling plan for on site welding, and inspection and test records. For butt welds, it is recommended that at least one weld at the start of each day of welding be tested; depending on the joint type, diameter and other risk factors, the frequency of weld testing may be increased or reduced at the discretion of the Water Agency or project manager. For electrofusion welds, it is recommended that at least one weld in 20 be chosen at random for destructive testing; the frequency of weld testing may be reduced at the discretion of the Water Agency or project manager. It is also recommended that quality records for each weld, numbered and located on a plan of works, be retained for at least 6 years from the date of installation. For guidance on welding procedures, equipment and quality assurance refer to UK Water Industry Specification WIS 4-32-08. 2.13 TESTING AND COMMISSIONING 2.13.1 General Pressure testing PE pipes may require special processes since they may continue to expand significantly throughout the test period. When a PE pipe is sealed under a test pressure there may be decay, even in a leak free system, due to the creep response and stress relaxation of the PE material. Due to this material behaviour, standard pipe testing procedures used for other pipe materials such as DI and steel, may not be suitable for PE pipe. The following factors can affect a PE pipe pressure test: (a)
length of section and pipe diameter;
(b)
test pressure, rate of pressurisation and duration of the test;
(c)
presence of air;
(d)
relative movement of mechanical fittings;
(e)
level of support from pipe embedment;
(f)
accuracy of test equipment;
(g)
ambient temperature changes during testing;
(h)
presence of fittings and other materials in the test section; and
(i)
the presence of leaks.
Long test sections may incorporate a large number of joints that should be checked for leakage. The longer the test section the harder it is to locate a leak. Pipes above about DN 250 cause additional effects to further complicate the test process. Where site or production reasons require longer lengths to be tested, radio links between test operatives to minimise the test duration should be employed.
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2.13.2 Pre-Testing Procedures Test pressures shall not exceed the design safety factor for the material and compressed air testing shall not be permitted for pressure pipe. Pre-testing procedures include the following: (a)
All required temporary and permanent thrust blocks shall be in place and all concrete adequately cured.
(b)
All bolted joints shall be left exposed to allow for re-tensioning during or after testing.
(c)
Compacted embedment and backfill shall be placed to leave exposed all joints, service connections and valves wherever practicable.
(d)
Safety barriers shall be placed where required.
(e)
The test duration shall be planned to be 15 minutes or no more than 45 minutes.
(f)
The test equipment shall be placed in position and checked for satisfactory operation.
(g)
The pump shall be of adequate size to raise and maintain the test pressure. A pump that is too small may increase the test duration or if too large it may be difficult to control the pressure.
(h)
Two calibrated test gauges shall be used to cross check gauge accuracy.
(i)
The pipeline shall be filled from the lowest point making sure all air is removed at high point appurtenances e.g. air release valve, hydrant etc; A firm foam swab may be used ahead of the fill water to assist air removal especially where the pipeline undulates. Extract the swab at the high point hydrant or washout.
(j)
The test section shall be left to stabilise overnight or for at least 2-3 hours if this is not possible.
2.13.3 Test procedure selection The objective of the pressure test is to test the jointing and fittings, not the material capability. Unless otherwise specified, the basic pressure test (visual) shall be used for installations using both standard trenching and rehabilitation techniques. The general pressure test (technical) shall be used for the remaining installations and in the case of dispute when using the basic pressure test. With a safety factor of 1.25 for PE coupled with relatively flat regression curves, the maximum test pressure and test duration for testing shall be reduced whenever there is elevated (>20ºC) temperatures during testing (refer to f1 in Table 2.3). 2.13.4 Basic pressure test (Visual) The visual pressure test procedure shall be as follows: (a)
A test pressure of 1.25 times the maximum operating pressure shall be applied and the test section isolated by closing the high point air release valves and the pump feed valve;
(b)
The test section shall be visually inspected for leakage at all joints especially bolted joints, all fittings, service connections and ball valves;
(c)
Pressure gauges shall be checked to ensure that pressure has not fallen dramatically indicating an undetected leak;
(d)
Any detected leak shall be repaired and the section retested;
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(e)
Where no leak is detected, open high point appurtenances and depressurise to slowly drain the line into an approved waterway and make good all connection points.
(f)
The location of the test section, the water temperature, test pressure and duration, the date and the test results shall be recorded.
2.13.5 General pressure test (Technical) 2.13.5.1 General The WSA 01-2001 method was based on the WRc method, which has been further modified by G.P. Marshall et al. The method is known to have failed pipelines that were not leaking, whereas the proposed method is simpler and has been used successfully since 1989 for LDPE, HDPE, and MDPE pipelines with lengths up to 3,000 m and diameters up to 800 mm. Both the WRc and modified methods were based on constant wall strain, resulting in stress relaxation and consequent pressure decrease. These methods relied upon broad assumptions concerning soil support, pipe material modulus, and air entrapment. i.e. the pass/fail criteria for the pressure decay curves were dependent upon these assumptions. Consequently, these methods were found to be unreliable as an assessment of pipeline integrity. Regarding pipe material modulus, the value is stress, time, and temperature dependent, involving further guesswork. In addition, the PE 80B and PE 100 materials cover a wide range of moduli, even for the outdated assumptions of MDPE for PE 80B and HDPE for PE 100. Within these material categories we now have PE 80B HDPE, bimodal as well as MDPE, and, for PE 100, we have HDPE. In relation to field pressure testing, a generic modulus can no longer be assumed for PE 100, as the introduction of low sag materials has meant a wide range of values even within the HDPE category. Estimation of soil support over pipeline length involves even more guesswork. The WSA 01—2003 method proposed is not only simple and proven, but does not involve the guesswork and potential unjustified penalties to installers of the current method. A procedure for pressure testing PE pipelines has been developed in Scandinavia and is outlined in “Plastics Pipes for Water Supply and Sewerage Disposal” by Prof. Lars-Eric Janson, and PIPA Technical Paper “Field Pressure Testing”. It is specified in AS/NZS 2566.2 and Swedish Water and Wastewater Works Association specification “VAV P78”. The test procedures set out below are based on these documents. 2.13.5.2 Test principle For plastics pipes that are subjected to internal pressure, there will be a progressive drop in that pressure due to stress relaxation. Accordingly, it may be difficult to assess whether a pipeline is leaking or simply subject to stress relaxation. In order to overcome this difficulty, this method is based on the principle that if the pressure is held constant, there will be a linear relationship between hoop strain and logarithmic time. Variables such as pipe stiffness and soil compaction are irrelevant, as the test result is based on actual performance during the test. Temperature may be considered constant, as with other test methods, unless special conditions exist.
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2.13.5.3 Test procedure Maximum system test pressure (STP) shall be at least 1.25 times the maximum working pressure of pipeline but not to exceed 1.25 times MAOP of lowest rated pipe/fitting in line. Test the pipeline as follows: (a)
Raise pressure to STP, close off main and allow to settle for at least 12 hours. During this period, pressure will fall as a result of pipe expansion.
(b)
Using water of the same temperature as that in the pipeline (± 3°C) restore maintain STP
(c)
Measure and record water volume added at 2h, 3h, 4h, and 5h from start.
(d)
Conclude test 5 hours after commencement.
and
For optimum test protocol, the following tolerances are recommended: (i)
Water volume: ± 10D litres, where D = pipe nominal diameter in metres.
(ii)
Time: ±1 min.
(iii)
Pressure: ± 1 kPa.
Suggested tolerances are included even though the current method does not include tolerances. Accordingly, they are included as recommendations only. (e)
Calculate the water volume added between the second and third hour, ∆V(3h-2h) and the volume added between the fourth and fifth hour, ∆V(5h-4h).
(f)
Calculate Vall = 0.14.L.D.H (ref. AS/NZS 2566.2, Section 6.3) where: Vall = Volume makeup allowance in litres/hour L = Test length in km D = Pipe nominal diameter in metres H = Average test head over pipeline length in metres
(g)
Test passes if ∆V(5h-4h) ≤ 0.55 ∆V(3h-2h) + Vall.
(h)
Record the location of the test section, the water temperature, test pressure and duration, the date and the test results.
2.13.6 Commissioning The flushing and disinfection methods in WSA 03 shall be adopted for PE pipe. These methods may be adapted to meet particular PE installation conditions, eg. pre-chlorination of sliplined mains. 2.14 MAINTENANCE 2.14.1 Post installation works For post installation tee insertion in pipe up to DN 90, compression fitting assemblies shall be used. For pipe larger than DN 90, either electrofusion saddles or electrofusion slip couplings or mechanical slip couplings that comply with AS/NZS 4129 shall be used. Because of the general absence of anchor blocks in PE pipe systems, caution should be exercised when specifying the use of non-end thrust resistant fittings such as wrap-around stainless steel flanged off-take clamps for post installation works. 2.14.2 Repairs For pipe up to DN 90, repairs shall be undertaken using compression couplings. COPYRIGHT
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For pipe above DN 90, repairs shall be performed using electrofusion slip couplings, compression fittings conforming to AS/NZS 4129 or wrap around stainless steel clamps complying with AS 4181 (Refer to caution in Clause 2.14.1). Mechanical repair couplings (Gibault type couplings) using a compressed circular rubber ring shall not be used for repair of PE pipelines. Stainless steel wrap around clamps provide no axial restraint. In some circumstances the installation of these clamps may need to be accompanied by the installation of anchor or thrust blocks. Some axially restrained stainless steel couplings up to DN 160 can be used with out anchor blocks. 2.14.3 Squeeze-off 2.14.3.1 Background The use of PE pipe is an attractive proposition particularly for smaller diameter pipelines given that the squeeze-off technique can be used for isolation in the event that maintenance is required. By using PE there is no need for any isolation valve either at the pipeline or along any connecting service pipe. However, if replacement of the squeezed-off PE pipe section is required, then the proposition becomes decidedly less attractive. In the U.K., the water industry does not mandate that the squeezed-off part be subsequently cut out and replaced. Advice provided by Wavin, U.K. is that: "On release of the squeeze, the pipe should be: (a)
Inspected and re-rounded if necessary.
(b)
Renewed if there is any indication of damage (e.g. cracking or splitting).
(c)
Adequately marked and recorded (e.g. marked "squeezed" at the point of compression)".
These UK recommendations are for pipes up to and including 500 mm diameter i.e. DN 500. Freeze-off has been successfully applied in Australia especially with the smaller diameter PE pipes commonly used in property service connections. Freeze-off is not used in the U.K. Some objections from the U.K. to freezing are: (i)
The time taken due to the relatively poor thermal conductivity of PE cf. copper.
(ii)
A health and safety issue concerning "working with your head in a pool of CO 2".
In Australia the freeze-off technique is not considered to be a problem, except that the freezing time will obviously be longer than for metallic pipes. If there is a genuine OH&S issue with the use of CO2 then it is indeed an issue that applies to all pipe materials that employ this technique e.g. copper. 2.14.3.2 Recommended squeeze-off practice Where PE pipelines are isolated in an emergency using the squeeze-off technique, only specially designed squeeze-off tools shall be used to avoid over compression and minimise damage. Since the pipe will always be damaged by squeeze-off, the damaged area shall be cut out and replaced at the earliest practicable time. Under no circumstances shall the PE pipe be bent backwards to stop the flow unless the pipe is to be replaced back to at least 5 pipe diameters from point of isolation. For squeeze-off up to and including DN 50, it is recommended that the U.K. approach be adopted i.e. only cut out and replace in the event of visible damage, and mark the PE pipe as squeezed using a suitable marker tape. COPYRIGHT
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Alternatively, freezing may be used using the standard equipment that is currently used for copper pipe. 2.15 ELECTRICAL SAFETY PE pipe is a poor conductor of electricity. In the majority of older properties in Australia, a buried metallic water service pipe is used either as the main earth or is bonded to the earthing system. If this earthing arrangement is destroyed or modified, it may create an electrical hazard under some conditions. To avoid creating an electrical hazard, precautions need to be taken where metallic water services (and in some cases the water main), which form part of the property electrical earthing systems, are replaced with PE pipe. Wherever metallic pipe systems are replaced with PE pipe, the property electrical earthing system shall be checked and where necessary made safe by a licensed electrical contractor.
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3 NON-PRESSURE PIPELINES 3.1 GENERAL PE pipes and fittings for gravity sewers, drains and other non-pressure pipelines shall comply with AS/NZS 5065. PE maintenance shafts shall comply with AS/NZS 4798. Requirements for other PE products used in non-pressure pipelines and additional requirements for non-pressure pipelines are set out below. 3.2 COMPOUND DESIGNATION Compounds that comply with AS/NZS 4131 (Refer to PIPA Guideline POP004 for a list of complying compounds) or the compounds specified in the relevant product standard shall be used. 3.3 PIPELINE SIZES For sewers, sizes DN 110, 125, 160, 180, 280, 355, 450 and larger sizes as listed in the relevant product standard (refer to Clause 3.1) shall be adopted unless otherwise specified (Refer to manufacturers for available pipe sizes). 3.4 STIFFNESS [SN] Unless otherwise specified, minimum stiffness class of sewers shall be SN 8. For other applications, stiffness classes shall be determined in accordance with AS/NZS 2566.1. 3.5 COLOUR Buried pipe for gravity sewerage applications shall be black or black with a co-extruded internal white or natural liner so as to permit accurate inspection and coding of the sewer condition using CCTV equipment. Buried fittings shall be black. The contents of above ground pipelines shall be identified in accordance with AS 1345. 3.6 STORAGE Pipe and fittings shall be stored as follows: (a)
All pipe shall be stacked in a manner to minimise pipe ovalisation.
(b)
Fittings and sealing materials shall be left in the original sealed cartons until used and stored in secure areas away from direct sunlight.
For solid black pipe, fittings and fabrications outside storage can be unlimited. Large diameter pipes and fabrications, such as maintenance shafts, may require special provision to preserve dimensional properties. 3.7 STANDARD LENGTH Unless otherwise specified, the industry standard lengths for gravity sewers shall be nominal 12 m. Other lengths (6, 15 and 20 m) may also be supplied to order. Designers should check with manufacturers for their nominated standard lengths and that longer lengths are transportable to site and able to be handled on site.
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Coiled PE pipe when removed from the coil or drum will be oval and curved. The extent of ovality and curvature will depend upon the ambient temperature, SDR, pipe diameter, coil diameter and compound type. Coiled pipe is usually limited to a maximum of DN 125. The use of coiled pipe is also limited by the requirement to lay gravity sewers on grade within specified construction tolerances (Refer to WSA 02). Where both ovality and curvature can be reduced to an acceptable level by suitable coil handling and levelling equipment to facilitate handling, jointing and laying on grade, then coiled pipe may be suitable for gravity sewer installations. 3.8 FITTINGS PE Fittings for non-pressure sewers shall: (a)
be preferably fully moulded;
(b)
comply with AS/NZS 5065; and
(c)
be SDR 33 or thicker for MH drop assemblies and for above-ground applications.
Bends formed from pipe, shall have a minimum wall thickness not less than the pipe to which they are to be connected. Depending on the forming process and the amount of wall thinning produced, the pipe used to forms bends may need to be thicker (lesser SDR) than the pipe to which it is to be connected. 3.9 PIPELINE DESIGN 3.9.1 System Life The life of non-pressure PE pipelines will be dependent on performance under four main conditions: (a)
Soil mechanics and pipe mechanics stability.
(b)
Pipe material strength.
(c)
Chemical and biological stability.
(d)
Functional stability.
The life of thermoplastic non-pressure pipeline systems has been extensively studied and reported. For example, the report titled "Plastics Pipes—How Long Can They Last", by Prof. Lars-Eric Janson of VBB Sweco Consulting Group reaffirmed a 1987 report concluding that the answer to the above question was "at least 100 years". The latest report, produced in 1996, states that "...it has been clearly found that nothing has emerged, which contradicts the statement made in 1987." It also states that the report refers mainly to buried gravity sewer pipes, but the conclusions can in most cases be applied for pressure applications. The aim of the work was to verify the claim of "at least 100 years". The summary states that "…one can thus conclude that everything is pointing to at least 100 years practical service life for today's buried sewer pipes made of high quality virgin PVC-U and PE resins, on condition that the pipes are used in accordance with the prevalent national standard installation instructions." Provided that PE pipeline system components are appraised and supplied to nominated industry standards under third-party product certification systems, and provided pipelines are designed and constructed correctly, then the likelihood of failure is minimised. For correctly manufactured and installed systems, the actual life can not be predicted, but can logically be expected to be well in excess of 100 years before major rehabilitation is required. COPYRIGHT
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If a system life is to be assigned beyond 100 years, it shall be based on the likelihood of failure arising from the above factors. 3.9.2 Structural Pipeline structural design shall comply with AS/NZS 2566.1. 3.9.3 Hydraulic Pipeline hydraulic design shall comply with WSA 02 or as nominated by the Water Agency. 3.9.4 Environment Where the pipeline is to be installed in suspected contaminated ground, specific soil sampling shall be undertaken to identify reagents in the ground and surrounding groundwaters. Contaminated soils deemed to be damaging to PE (Refer to Clause 2.10.5) shall be removed from site. Where leaching of contaminants into the pipe alignment may re-occur the PE pipe shall be contained in an impervious sealed conduit. The properties of PE make such pipelines particularly suitable for areas subject to ground movement due to expansive clays, seismic forces, mining subsidence or compaction of filled sites. In addition fusion jointed PE pipelines provide a high degree of confidence in pipeline integrity and therefore suitability for installation in areas of environmental sensitivity where exfiltration cannot be tolerated. The information in AS 2033 Appendix A relates to constant exposure to the chemicals concerned. Ground contaminants are often only present in small quantities or concentrations. In these circumstances, the advice of the manufacturer should be sought. 3.10 INSTALLATION 3.10.1 Trenching and embedment Trenching and embedment shall be in accordance with: (a)
firstly the Design Drawings;
(b)
secondly WSA 02 and the Standard Drawings included therein; and
(c)
thirdly AS/NZS 2566.2.
For additional information refer to the Standard Drawings in Appendix C and WSA 02. 3.10.2 Pipelaying Pipelaying shall be in accordance with WSA 02 and the following requirements: (a)
PE pipes shall be installed to allow for the difference in ambient temperature and the in-ground temperature.
(b)
PE pipes shall be laid in the trench to line and level with full embedment and partial trench backfill without restricting the ends until the pipe has had time to stabilise to ground temperature.
(c)
Installations using directional drilling or similar processes should be considered on their merits with respect to grade, alignment, ground conditions, obstructions and environmental considerations.
3.10.3 Property connection sewers and maintenance shafts PE property connection sewers (also known as property branches or sidelines) shall be constructed in accordance WSA 02 and the Water Agency’s requirements. Property connection sewers constructed from PVC shall have a junction fitting included in the reticulation sewer and the conversion from PE to PVC shall be adjacent to this junction. Conversion from PE to PVC shall be by means of metal-banded flexible coupling with shear band. COPYRIGHT
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PE maintenance shafts (MS) shall be fusion jointed to the sewer. 3.10.4 Jointing Butt welding or electrofusion jointing shall be used. Only trained and certified welders shall perform weld jointing of pipelines. (refer to Section 5). Removal of the internal weld bead in butt welded gravity sewers is not considered necessary from hydraulic considerations, except in gravity sewers graded 1 in 40 or flatter or where dry weather velocities do not exceed 0.3 m/s. Connections to PVC/ABS/DI/steel pipelines shall be made using PE flange adaptors to AS 4087 Figure B2 requirements using stainless steel backing plates and fasteners. Connections to VC/GRP/RC pipelines shall be made using a spigot end adaptor welded to the PE pipe spigot, and utilising the socket and sealing ring of the VC/GRP/RC pipe. 3.10.5 Maintenance holes and maintenance shafts For connection of PE pipe to concrete MHs, use a one size larger diameter PVC (AS/NZS 1260) sanded elastomeric seal joint coupling cast into the MH wall. A fabricated thick wall section PE spigot fitting with outside diameter to match the coupling ID, butt welded to the PE sewer pipe shall be inserted into the PVC socket accordingly. A puddle flange and concrete anchor shall be used either side of the MH to maintain the pipe location in the PVC socket. Typical construction details for MH connections are shown in Standard Drawing SEW– 1317. For PE MHs and MSs, butt welding or electrofusion jointing shall be used to seal the entry/exit of PE sewers to the MH or MS. For drop assemblies contained within the MH, the pipe and fittings shall be SDR 33 or thicker. For guidance on restraining MH drop assemblies refer to Standard Drawing SEW– 1306. 3.11 WELD PRE-QUALIFICATION 3.11.1 Butt fusion Refer to Clause 2.12.1. 3.11.2 Electrofusion Refer to Clause 2.12.2. 3.12 TESTING Non-pressure PE pipelines shall be tested for leakage using low pressure air testing or hydrostatic testing in accordance with the procedures outlined in AS/NZS 2566.2. All acceptance testing shall be performed after backfilling. Where specified, non-pressure PE pipelines shall be deflection tested in accordance with AS/NZS 2566.2. To allow for stabilization of the pipe soil system, deflection testing shall be conducted at a specified period after installation nominated by the Water Agency. To ensure accurate measurements the pipeline shall be cleaned before deflection testing. The testing will detect damaged piping or improper jointing, but cannot be used as a quantitative measure of leakage under service conditions for infiltration or exfiltration. A standard test method for installation acceptance of plastic gravity sewer lines using low pressure air is also published by ASTM, viz F1417. The time between the completion of the backfill operation and testing may be specified by the Water Agency. The test may also be
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used as a preliminary test that enables the installer to show the condition of a buried line prior to the final backfill, paving and other construction activities. The vertical deflection of the installed pipeline should be determined either by direct measurement, or indirect measurement using devices such as electronic deflectometers and calibrated television or video cameras. Pipelines jointed by butt welding may require the internal weld beads removed, depending on the deflection testing method used. Passing an internal proving plug through the pipeline is not recommended. ASTM D2321 Standard Practice for Underground Installation of Thermoplastic Pipe for Sewers and Other Gravity Flow Applications recommends that deflection tests should be performed at least 30 days after installation, but advises, as a quality control measure, that periodic checks of deflection be made during installation. ASTM F894 Standards Specification for Polyethylene (PE) Large Diameter Profile Wall Sewer and Drain Pipe recommends a maximum acceptance deflection of 7.5% at 30 days minimum. 3.13 MAINTENANCE 3.13.1 Post installation connections Connections shall be made using either: (a)
slip type electrofusion couplings; or
(b)
fabricated stainless steel spigot slope junctions complying with the performance requirements of AS 4181; or
(c)
electrofusion saddles.
3.13.2 Repairs Repairs shall be undertaken using electrofusion slip couplings or stainless clamps complying with AS 4181.
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4 RELINING APPLICATIONS 4.1 GENERAL A common relining technique for the rehabilitation of both pressure and a non-pressure pipeline, which utilises the material characteristics of PE, is sliplining. This technique consists of inserting a pre-welded length of PE pipe into the host pipe that requires rehabilitation. The normal process uses pipe of full specification that can be regarded as an independent pipe. This leaves an annular space between the new pipe and the old that should be grouted. New variants include 'Rolldown', 'Swagelining', 'Fold and form', 'U-liner' and 'Cold die drawn lining'. These methods eliminate the annulus, together with the need for grouting, the new pipe having an interference fit with the old. Pipe cracking or pipe bursting is an alternative to sliplining where size for size or larger sizing is required. This involves breaking the existing pipeline, pushing the fragments into the surrounding embedment, pulling through a new PE pipe. Pipes as large as or larger than the original pipe can be used. Dependent upon the criticality of the pipeline requiring rehabilitation, some pipe cracking or pipe bursting installations may require the use of a sleeve pipe that is sliplined using a new PE pipe. Many of these techniques are specialised and registered or even patented systems, which are beyond the scope of this Code. 4.2 MATERIALS The requirements listed in Sections 2 and 3 of this Code shall apply for pressure and nonpressure relining systems, respectively. 4.3 PIPE Relining pipes shall comply with EN 13566-1, prEN 13566-2, EN 13566-3 and EN 13566-4 as appropriate to the relining technique being used and those listed below. 4.3.1 Nominal diameters Pipe diameters shall be selected from the sizes listed in AS/NZS 4130 to provide the closest fit inside the pipe or bore provided. 4.3.2 Length For relining applications of pipe diameters up to DN 125, pipe coils shall be used. For pipe diameters larger than DN 125, the pipe shall be in longest manageable straight lengths. 4.3.3 Colour Colour requirements for pressure (Clause 2.6) and non-pressure pipe (Clause 3.5) shall be used for relining applications, where the host pipe does not remain intact eg, pipe cracking. Gravity sewer relining applications shall be black with a co-extruded internal white or natural liner. 4.4 FITTINGS Fittings for relining applications shall follow those adopted for pressure and non-pressure pipe systems in Sections 2 and 3 respectively.
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4.5 PIPELINE DESIGN Pipeline design for relining applications shall follow the principles adopted for pressure and non-pressure pipe systems in Clauses 2.10 and 3.9 respectively. 4.6 INSTALLATION 4.6.1 General Unless specified below the installation requirements specified in Clauses 2.11 and 3.10 shall apply. For non-pressure applications, grouting shall be applied between the liner and existing pipe where a gap exists. Grout shall be applied around all branch junctions for non-pressure applications. During installation of the PE pipe from the surface into the host pipe at the bottom of the trench, suitable mechanical handling precautions shall be adopted to ensure that the relining pipe is not damaged. 4.6.2 Jointing For safety reasons all main pipe fusion processes shall take place above ground except in circumstances where the contractor can demonstrate that it is not technically practicable. For pipe up to DN 90, either compression fittings or electrofusion jointing shall be used where space and installation conditions dictate. For PE pipe above DN 90, butt weld jointing shall be used. Elastomeric seal joints may be installed for non pressure PE sewers within contained spaces where grouting is applied in the annulus between the pipe and the bore hole where the rubber seal ring joint long term performance for contact pressure and width meets the requirements of AS/NZS 1260. 4.6.3 Connections Electrofusion couplings, electrofusion saddles or wrap around couplings shall be used (refer to Clauses 2.11.5 and 3.10.3), except that for pressure mains up to and including DN 63 bolt on bands with lip type seals may also be used. Post installation connections shall have the joints made by digging down to the connection point to install the connector. For connection to an MH or MS refer to Clause 3.10.5 of this Code. 4.7 RELINING TYPES 4.7.1 Sliplining For free inserted pipe, the insert pipe diameter may be up to 99% of the internal diameter of the existing pipe. As wall thicknesses of the host pipe are site specific, the external loads shall be evaluated in accordance with AS/NZS 2566.1, and maximum deflection be limited to 7.5% for long term and 4% for short term of the pipe outside diameter. Where specified, non-pressure pipelines shall be grouted and the grout pressures limited by external pressure capacity of pipe. A factor of safety of 2.0 against buckling shall be adopted. The bending radius of an inserted pipe shall be greater than 25 times the outside diameter of the pipe.
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For liner pipe pulled into existing cavities, the maximum end load shall be limited to that causing a maximum allowable strain for the pipe material. Liner pipe shall be allowed to relax after insertion for a period equal to the time of insertion loading. Reference may be made to the POLIplex Polyethylene Pipe Design Text Book (published by Iplex Pipelines Australia) in Section Seven (Table 7.6.5 on page 7-74) which sets out safe axial tensile loads in PE pipes. Where short length pipe sections are jacked into the existing line, the maximum jacking loads shall be limited to the load capacity of the specific joint type. Unless otherwise specified, a factor of safety of 2.0 shall be adopted. The controlling design feature for jacking sections, is the compressive bearing capacity of the joint section. Any particular joint design shall have load data prepared to establish jacking load capacity without compression collapse. 4.7.2 Pipe cracking and moling Where pipe cracking or moling is applied the PE pipe used shall be selected for normal pressure or external load considerations. 4.7.3 Swagelining Where swage, draw down or diameter reduction is used, the pipe shall be PE 80B or PE 100 material. The actual liner pipe diameters shall be established on a project by project basis as they are site specific. 4.8 TESTING The methods of testing specified for open trench installations shall be maintained for PE relining both in pressure and non-pressure pipelines.
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5 PERSONNEL QUALIFICATIONS 5.1 GENERAL The handling, laying, jointing, trench filling and testing of all water mains, construction and testing of associated structures and installation of appurtenances shall be carried out, and supervised by, acceptably qualified and/or accredited personnel. Personnel shall hold minimum qualifications or specialist accreditation appropriate for the work undertaken. Minimum qualifications shall mean Statements of Attainment for all those Units of Competence, nominated by the Water Agency, from the Water Industry National Training Package NWP2000 or Local Government Training Package LGA00 or the Civil Construction Training Package BCC98 or other relevant Training or a combination of one or more of the aforementioned. Specialist accreditation shall mean a qualification achieved through specialised training and assessment for a specific product and/or situation that is not covered by relevant Training Packages. Qualifications from Training Packages shall be awarded by a registered training organisation. Training and assessment for specialist accreditation shall be provided by registered training organisations or recognised organisations with appropriately qualified and experienced trainers and assessors. Registered training organisations shall be those listed by the National Training Information Service for the provision of training or assessment services as required. Training packages, together with relevant short training courses and training/assessment service providers are provided by the National Training Information Service at www.ntis.gov.au/. 5.2 WELDING The welding of components shall be carried out, and supervised by acceptable qualified and/or accredited personnel, who have successfully undertaken the following Units of Competence of the Plastics, Rubber and/or Cablemaking Training Package PMB01 appropriate to the welding processes used: (a)
PMBWELD301A—Butt weld polyethylene plastic pipelines
(b)
PMBWELD302A—Electrofusion weld polyethylene pipelines
“Successfully undertaken” shall mean “Statement of Attainment” for all those appropriate Units of Competence. Only personnel who have successfully completed the above training programs shall be permitted to work on PE systems. Certification shall be valid for 2 years and be limited to the actual materials, sizes, and equipment covered in the specific training program. At the end of this period, renewal of the certification shall be required. Certified welders shall demonstrate continuous welding activity and any break of more than six months shall require renewal of certification. Certification details shall be carried by field personnel on-site, and be made available as required.
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The training organisation shall maintain a database of course participants and their certification status for access by contract principals as required for specific installation projects. 5.3 TRENCHLESS TECHNOLOGY The use of trenchless technology including relining applications outlined in Section 4 shall be carried out, and supervised by acceptable qualified and/or accredited personnel, who have successfully undertaken the following Units of Competence of the Civil Construction Training Package BCC30903. “Successfully undertaken” shall mean “Statement of Attainment” for all those appropriate Units of Competence. Only personnel who have successfully completed the above training programs shall be permitted to work on PE systems. Certification details shall be carried by field personnel on-site, and be made available as required.
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APPENDIX A EQUIVALENT PIPE DIAMETERS The following tables of equivalent pipe diameters have been produced to show the actual mean internal diameters of the CICL and AC water mains, laid extensively in the post World War II period to the mid 1970’s, compared to PE. Tables of equivalent pipe diameters with CICL and AC pressure pipes have been prepared from the pipe dimensions contained in Australian Standard Specification for Centrifugally Cast Iron Pressure Pipes for Water, Gas and Sewage (AS A145—1965) and Australian Standard Specification for Asbestos Cement Pressure Pipes and Joints (AS A41—1959). For CICL calculations, nominal values have been used, while for AC calculations, the internal diameters specified in the Standard were based upon minimum wall thicknesses. Class C CICL was most commonly used by Water Boards at that time, while for AC pipe individual Water Agency records should be consulted. For pipe materials used since the late 1970’s consult current Australian Standards.
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TABLE A1 TABLE OF EQUIVALENT PE PIPE DIAMETERS CICL PRESSURE PIPE AS A145—1965 CICL
PE
Size in/DN
Class
Mean ID* in/mm
DN
PN
Compound
Mean ID mm
4/100
C
3.68/93
110
12.5
PE 80B
89
D
3.60/91
PE 100
93
PE 80B
84
PE 100
89
PE 80B
101
PE 100
106
PE 80B
96
PE 100
101
PE 80B
130
PE 100
136
PE 80B
123
PE 100
130
PE 80B
146
PE 100
153
PE 80B
138
PE 100
146
PE 80B
203
PE 100
212
PE 80B
192
PE 100
203
PE 80B
228
PE 100
238
PE 80B
215
PE 100
228
PE 80B
256
PE 100
268
PE 80B
242
PE 100
256
16
125
12.5
16
6/150
C
5.74/146
D
5.62/143
160
12.5
16
180
12.5
16
8/200
C
7.63/194
D
7.51/191
250
12.5
16
9/225
C
8.55/217
D
8.41/214
280
12.5
16
10/250
C
9.57/243
D
9.41/239
315
12.5
16
(continued)
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CICL
PE
Size in/DN
Class
Mean ID* in/mm
DN
PN
Compound
Mean ID mm
12/300
C
11.35/288
355
12.5
PE 80B
289
D
11.19/284
PE 100
302
PE 80B
273
PE 100
289
PE 80B
366
PE 100
382
PE 80B
346
PE 100
366
16
15/375
C
14.62/371
D
14.44/367
450
* Heavy lining thickness values applied. NOTE: Closest equivalent PE pipe size and compound combinations to match the CICL mean internal diameters can be determined by comparing mean internal diameters.
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TABLE A2 TABLE OF EQUIVALENT PE PIPE DIAMETERS AC PRESSURE PIPE AS A41—1959 AC
PE
DN
Class*
Mean ID mm
DN
100
B
101
125
C
97
PN 12.5
16
150
B
155
C
146
180
12.5
16
200
B
203
C
196
250
12.5
16
225
B
229
C
219
280
12.5
16
250
B
253
C
243
315
12.5
16
300
B
299
C
295
355
355
375
B
370
C
363
450
12.5
16
12.5
16
Compound
Mean ID mm
PE 80B
101
PE 100
106
PE 80B
96
PE 100
101
PE 80B
146
PE 100
153
PE 80B
138
PE100
146
PE 80B
203
PE 100
212
PE 80B
192
PE 100
203
PE 80B
228
PE 100
238
PE 80B
215
PE 100
228
PE 80B
256
PE 100
268
PE 80B
242
PE 100
256
PE 80B
289
PE 100
302
PE 80B
273
PE 100
289
PE 80B
366
PE 100
382
PE 80B
346
PE 100
366
* Class B = 122 m head Class C = 183 m head NOTE: Closest equivalent PE pipe size and compound combinations to match the AC mean internal diameters can be determined by comparing mean internal diameters.
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APPENDIX B REFERENCES FOR USE BY DESIGNERS WHEN MANAGING THE RISK OF INSTALLATION, OPERATION AND MAINTENANCE OF PE PIPELINE SYSTEMS IN CONTAMINATED LAND Laying Potable Water Pipelines in Contaminated Ground—Guidance Notes Report FR 0448 Nov 1994 Foundation for Water Research. BSI (1988) Draft for Development Code of Practice for the Identification of Potentially Contaminated Land and its Investigation, DD 175:1988. Construction Industry Research and Information Association, (1993) Guide to Safe Working Practices for contaminated Sites, CIRIA, London. Protection of Workers and the General Public during Development of Contaminated Land (1991) Health and Safety Executive, HMSO, London. Arnaout S and Peck R R (1988) Pipe Line Installation in Contaminated Land WRc Report ER 319E. Wilson I and Norris M (1992) Effects of Organic Chemicals in Contaminated Land on Buried Services, WRc report for the Department of the Environment DoE 2982-(P). Contaminated sites: legal and financial responsibility, and planning solutions/report prepared by national Capital Planning Authority for Better Cities Program AGPS 1993.
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APPENDIX C STANDARD DRAWINGS C1 GENERAL Standard Drawings that support Polyethylene Pipeline Code are included to assist understanding of the principles and methodology involved in construction of PE pipeline systems and to enhance the design and construction requirements of this Code and should be read in conjunction with them. The Standard Drawings provide a “Deemed to Comply” solution for the installation of particular elements of a water supply or sewerage system that are specific to PE. Standard Drawings of other WSAA Codes should also be referenced as appropriate. However, the Drawings will not suit all circumstances or overcome all problems. To meet special needs, Designers and Constructors are encouraged to identify improved construction methods and other variations from the requirements set out in the drawings. Approval from local Water Agencies will be necessary before any major departures from the principles outlined in the drawings are implemented. Successful initiatives will be considered by WSAA for inclusion in future editions of this Code. All Design Drawings should include the name of the Water Agency and have a signature block to allow confirmation that each drawing complies with Water Agency requirements. The symbols and markings used on these Drawings are typical only and do not apply to any particular Water Agency (Refer to the individual Water Agency for their legend, symbol and layout requirements). Individual Water Agencies may have specific information and presentation requirements, which should be determined before commencing any project. Any additional information, layout or format requirements specified by the Water Agency take precedence over these Drawings. All special requirements including, but not limited to geotechnical requirements, embedment and compaction details, should be shown in the Design Drawings and/or the Specification.
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C2 LISTING OF STANDARD DRAWINGS DRAWING NUMBER
ACTIVITY
TITLE
Equivalent 1999 DRAWING NUMBER
PIPELINE LAYOUT WAT–1102
Typical Mains Construction
Reticulation Main Arrangements
WAT–200 WAT–201
WAT–1104
Typical Mains Construction
DN 63 PE Cul-de-Sac Arrangement
WAT–1105
Typical Mains Construction
Connection to Existing Mains
WAT–202
EMBEDMENT / TRENCHFILL AND RESTRAINTS WAT–1201
Embedment & Trenchfill
Typical Arrangement
WAT–100
WAT–1211
Buried Crossings
Under Obstructions
WAT–105
INSTALLATION PRACTICES/ STRUCTURES WAT–1313
Flanged Joints
Bolting Details
FABRICATION DETAILS WAT–1409
Hydrant Installation Fittings
PE Assemblies
PE–14
ACCESS STRUCTURES
SEW–1306
Maintenance Holes
Alternative Drop Connections
SEW–206
SEW–1317
Maintenance Holes
Typical MS Cover Arrangements
SEW–212
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