Pipelines

Working near our Pipelines

Guidance for planning and working near our

pipelines

November 2009

Working Near

Water Corporation Pipelines

Guidance for planning and working near Water Corporation pipelines

November 2009

Working Near Corporation Pipelines

Copyright notice

This work is copyright. You may download, display, print and reproduce this material in

unaltered form only (retaining this notice) for your personal, non-commercial use or use

within your organisation. Apart from any use as permitted under the Copyright Act 1968, all

other rights are reserved. Request for further authorisation should be directed to the

address below.

Enquiries

Enquiries with respect to the content of this guideline are to be directed to:

Manager Maintenance Management

Tactical Asset Management

Planning and Capability Group

Water Corporation

PO Box 100

Leederville

WA 6092

Phone 9420 2420

Enquiries with respect to application of these guidelines to particular work are to be directed

in the first instance to 131375.

This document is subject to change without notice. The latest version can be downloaded

from the Water Corporation website.

Date Revisions Approval

Nov 2009 First issue S. Wisdom

Working Near Water Corporation Pipelines

Contents

1 General information 1

1.1 Introduction 1

1.2 Who does this guideline apply to? 1

1.3 Legislative requirements 2

1.4 Working on Water Corporation sites 3

1.5 Duty of care 3

2 About water pipelines 3

3 Site safety 7

3.1 Responsibility for site safety 7

3.2 Hazards associated with working near water infrastructure 7

3.3 Health risks from contact with wastewater 7

4 Planning considerations 9

4.1 General responsibilities for parties working near Water Corporation pipelines

9

4.2 Plan the work early 9

4.3 Do a damage risk assessment 10

4.4 About Water Corporation plans 11

4.5 Documentation to be kept on site 12

4.6 Locating assets on site 12

4.7 Guidance for planners and project managers 13

4.8 Guidance for site supervisors, excavators, site workers, machine operators

14

4.9 Guidance for services locators 15

5 Notification of planned work 17

5.1 When must the Water Corporation be notified? 18

5.2 How to notify the Water Corporation 18

5.3 Damage risk assessment 19

6 Technical considerations for works near pipelines 20

6.1 Access 20

6.2 Alignments 20

6.3 Asset Protection Officers 21

6.4 Blasting 21

6.5 Buildings, obstructions, or storage of materials over a main 21

6.6 Cathodic protection / electrical mitigation systems 22


6.7 Chemical discharges and spillages 22

6.8 Clearances to adjacent assets 22

6.9 Clearances to overhead structures 23

6.10 Damage to pipelines 24

6.11 Depth of cover 24

6.12 Emergency works 25

6.13 Excavations 25

6.14 Excavations - trenchless 25

6.15 Exposing pipelines 27

6.16 Mains on private property 29

6.17 Manholes / access chambers 29

6.18 Marker tape and tracer wires 30

6.19 Monitoring site works 31

6.20 Pipeline fittings and structures 31

6.21 Potholing 33

6.22 Power installations - poles 34

6.23 Power installations – directional drilling 35

6.24 Soil anchors 35

6.25 Trees and vegetation 36

6.26 Vehicles, access roads and tracks 36

6.27 Vibratory compaction 37

6.28 Warning markers and signs 38

7 Definitions 39

Appendix 1 – Applicable legislation 40

Appendix 2 – Useful pipeline protection planning checklist 49

Appendix 3 – References 51


1 General information

1.1 Introduction

This document is a guide for anyone planning and conducting works near Water

Corporation water, sewerage and drainage pipelines. The aim of this document is to

assist with the planning and conduct of site works so they do not interfere with water

infrastructure or the delivery of services, now and into the future.

Damage or other interference to water infrastructure can have significant impacts on

individuals, businesses and the community.

This guideline will enable planners, constructors, supervisors, excavators, etc. to better plan

their works and ensure that appropriate measures are taken throughout their project to

protect pipelines.

Parties working on site are responsible for the equipment and methods used in their work.

In providing this guideline, the Water Corporation is not specifying particular systems of

work or equipment to be used. It is instead identifying the various aspects of your work

which may have a undesirable impact on buried pipelines and providing guidance to you on

how to avoid these impacts.

It is the responsibility of the party conducting the work to determine how to best conduct

the work in consideration of this guidance information and applicable legal and regulatory

requirements.

This guideline describes important considerations during planning and site works. In some

circumstances Water Corporation requirements may differ from those specified in this

document depending on risks or other reasons.

This guideline relates only to work near Water Corporation buried pipelines. Owners of other

buried assets will have their own requirements which should be determined well prior to

commencing site work. Before commencing site work contact Dial Before You Dig on 1100

or at www.1100.com.au to request plans from the various asset owners.

Finally, in addition to protecting buried pipelines and other utilities services, there is a range

of other aspects which must be considered such as occupational safety and health (OSH)

requirements, local government requirements, environmental requirements, etc.

1.2 Who does this guideline apply to?

This guideline applies to anyone planning or conducting ground disturbing works in

the vicinity of Water Corporation pipelines.

http://www.1100.com.au/


What is “ground disturbing” work?

Ground disturbing work is any activity which penetrates or otherwise disturbs the ground. It

includes any activities which cause vibration, shock or application of excessive loads.

Ground disturbing work is often but not necessarily construction-related.

The intended readership for this document is therefore any party responsible for advising

on, planning or conducting construction or utility type works in the vicinity of Water

Corporation pipelines. This may include any of the following types of organisations or roles.

Who MUST KNOW ABOUT buried pipes?

Typical organisations Typical roles

construction companies

engineering consultancies

excavation contractors

farmers

geotechnical surveyors

head contractors

land developers

local government

owners of chemical or fuel

pipelines

rail authorities

road authorities

urban and rural landowners

utility service providers

architects

consulting engineer

designers

developers

planners

plumbers

project managers

site excavator

site supervisors

surveyors

utilities locators

1.3 Legislative requirements

The primary legislation applicable to this document are the various Western Australian

water and OSH acts. These are listed in the appendix.

Typical ground disturbing activities

boring

roadworks

siting and construction of access

roads

siting of laydown areas and

material stockpiles

digging open excavations

ground compaction

installation of soil anchors

pile driving

placement of temporary

structures

soil sampling

blasting

trenching

vertical or horizontal drilling


1.4 Working on Water Corporation sites

While this document is directed at works outside of Water Corporation sites, it is also

generally applicable to work conducted on such sites, but does not address all requirements.

Work on Water Corporation sites must be conducted in accordance with applicable Water

Corporation policies and procedures including any site-specific procedures. These

requirements will be communicated by the respective plant manager or person in charge of

the site as appropriate.

1.5 Duty of care

People working near water infrastructure have a duty of care to ensure that infrastructure in

the area is not damaged, or interfered with, and their work does not present a hazard to

workers or the public. This duty of care is exercised through careful planning of the works

and compliance with various requirements and conditions.

While the Water Corporation will provide plans, information and assistance where

appropriate, the responsibility for ensuring the work does not interfere with water

infrastructure and is conducted in a safe manner, remains with the party conducting the

work. Any damage caused, including potentially any consequential damages, is the

responsibility of the party who caused the damage.

People working near Water Corporation pipelines must positively verify the location of all

pipelines likely to be affected by their works. “Positively verify” means to pothole by hand,

or by other soft dig method, and prove the pipeline location visually.

2 About water pipelines

The Water Corporation operates $11 billion of water, sewerage and drainage infrastructure

throughout Western Australia - most of which is buried pipelines.

With increasing population densities and more and more facilities being installed

underground, there is increasing competition for space, and therefore there are increasing

risks that ground disturbing works may interfere with buried infrastructure.

Pipelines are designed to last 70 years or more. It is essential therefore that they are

protected from activities which could interfere with them and shorten their operating life.

One of the ways of ensuring that pipelines reach their design life is by reducing the chance

of interference by other works.

High pressures and flow rates

Many pipelines operate at very high pressures and carry significant volumes of water. Some

pipes are flowing continuously, others are intermittent in their operation. Wastewater


pumping stations and pressure mains carry raw untreated sewerage at high pressures and

flow rates. The unexpected sudden release of large volumes of water or wastewater from

these pipelines could be dangerous to persons working in the vicinity, and could result in

significant damage to nearby property and result in prosecution under various legislation.

Locations

While many pipelines are located in road verges and roadways, others can be found in

private property and in public open space. Often there is little or no indication at the surface

of the existence of any pipelines.

At any given location multiple pipelines may be found. These could have different functions,

criticalities, sizes, depths, alignments, and be constructed from different materials.

Therefore when planning site works it is essential to be certain of everything underground

that may be affected by the works. Locating one pipeline does not necessarily mean the rest

of the area is all clear. Some areas are particularly dense with buried pipes. See the

example below from the Perth metropolitan area.

Fig 2.1 – Part of a Water Corporation plan for a typical location in the Perth metropolitan area

showing multiple sewer and water pipes.


Pipe materials

Pipelines are constructed from different materials for different circumstances. Common

materials used today are steel, concrete, and PVC, however there are many other materials

in use. Some materials are more robust than others. Materials such as asbestos cement

(AC), cast iron (CI) and vitreous clay (VC) are relatively brittle materials and can be more

easily damaged than say steel. While newer pipelines are constructed of more robust

materials, there is a considerable quantity of older and less robust pipelines still in

existence.

Detection of buried pipes

Metallic and reinforced concrete pipelines which contain steel, may be detected by electronic

detection equipment, however non-metallic pipelines cannot be detected by this method.

This means that reliance on electronic detection equipment as the only means of identifying

location cannot be guaranteed. Pipe material may also change over a distance, sometimes

changing from metallic to non-metallic material and back again.

Pipe construction

Pipelines full of water are heavy structures. They are subject to strong forces so must be

well supported by soil and support structures especially at bends. Careless removal of soil

from pipelines and around foundations may cause differential movement resulting in

damage or failure.

Many pipelines have protective coatings on the inner and outer pipe surfaces to prevent

corrosion. These coatings only work if they remain undamaged.

Pipelines also have fittings and structures associated with them which also must be

protected. Some of these fittings and structures are:

anchor and thrust blocks

cathodic protection and other electrical protection systems

flow measuring equipment

manholes

sampling points

tanks

valves and valve pits

connection points

Consequences of pipe failure

A burst water or sewer main could have the following consequences:


Consequences of damaging a pipeline

injury or death

major transport disruption

local flooding

damage to other infrastructure

(e.g. utilities or civil structures

)

property damage

environmental damage

project delays

damaged reputation

repair costs

charges for lost water

damages claims

prosecution

higher insurance premiums

disruption of service

community inconvenience

Fig 2.2 - Flooding and disruption of the Kwinana Freeway resulting from a

damaged water pipeline.


3 Site safety

3.1 Responsibility for site safety

Parties working on site must have appropriate and effective methods in place to identify and

address hazards associated with working near water infrastructure. Parties need to take all

practicable steps to ensure that their work does not harm any other person, including site

workers, visitors to the workplace or the public.

3.2 Hazards associated with working near water infrastructure

While water infrastructure may appear to be less hazardous when compared with electricity

or gas services, hazards still exist and must not be underestimated.

Potential hazards are:

large forces associated with the release of water under high pressure

drowning or traffic hazards associated with the release of large volumes of water

biohazards associated with contact with wastewater (also see Section 3.3 - Health

Risks)

exposure to asbestos - asbestos cement pipe and some pipe wrapping

exposure to toxic gases in the wastewater system

exposure to hazardous waste discharged into the wastewater system

ignition of combustible gases in the wastewater system

electric shock arising from electrical infrastructure in the vicinity of a pipeline,

electrical faults or lightning

secondary hazards arising from damage or disruption to other structures or services

due to damaged water pipelines

fall hazards associated with accessing manholes or high structures

Unauthorised access to Water Corporation sites and assets, including opening of manholes

and access pits is hazardous and is prohibited.

3.3 Health risks from contact with wastewater

Contact with wastewater can be hazardous. Pathogens such as polio and hepatitis A viruses

may be present in the water. Other viruses and bacteria which may be present can cause

gastroenteritis and other infections.

Infection may occur through:

contact with open wounds and lacerations

contact by splashing onto mucous membranes such as eyes, nose and mouth


hand-to-mouth contact if thorough hand washing is not performed prior to eating,

drinking or smoking

poor hygiene practices such as taking contaminated clothing and footwear home

from the workplace

In the event of contact with wastewater the following actions should be taken:

cease work immediately

remove contaminated clothing

shower or wash down with plenty of water

use eye wash if eyes are contaminated

if wastewater is ingested, seek doctor’s advice immediately

if symptoms of nausea, vomiting, diarrhoea or fever develop seek a doctor’s advice

immediately


4 Planning considerations

4.1 General responsibilities for parties working near Water Corporation

pipelines

Parties working near Water Corporation assets must do the following:

positively identify all buried pipelines and associated equipment likely to be impacted

by the works

prevent damage or other interference to pipelines during the works or arising from

the works

notify the Water Corporation where required and comply with all conditions (see

Section 5 – Notification of Planned Work)

ensure all works are conducted in a safe manner and work methods adequately

address the hazards associated with the water pipelines

report any damage or faults to the Water Corporation on 13 13 75 (24 hours).

4.2 Plan the work early

Proper planning of works will minimise the risk of interference to buried pipes and avoid

costly project delays.

Dial Before You Dig

The first step is to request Water Corporation plans

from Dial Before You Dig (DBYD). Dial Before You Dig

is a free “one-call” referral service. This service

enables people planning work to easily request plans

from multiple asset owners who have assets in the

work area.

Water Corporation plans can be provided within 2 days by e-mail or fax. (Longer if surface

post is used.)

Plan requests can be made on-line at www.1100.com.au or by calling 1100.

These plans are the starting point. They enable planners, site supervisors, etc. to assess

what is in the ground and determine what steps, if any, need to be taken. Additional actions

may be required before any ground disturbing works can commence. It is not always

reasonable to expect to receive plans one day and start work the next. Sufficient time must

be allowed to plan and prepare for the protection of services. The appropriate actions will

depend on the types of pipelines in the work area and the intended work.

http://www.1100.com.au/


What to consider

The need to protect pipelines may impact the project in many ways. Here are the main

considerations:

choice of work methods – such as whether to use open trench or trenchless,

potholing, use of an excavation spotter

choice of construction equipment - such as excavation or compaction equipment

protection requirements – such as shoring, barricades, signs or marking out

site layout – such as access for heavy vehicles, spoil dumps, laydown areas and

temporary site structures

need for a specialist facilities locator – especially near major assets and congested

areas

sub-contractors and labour requirements

site supervision requirements

communications requirements - such as team briefings, issuing instructions and

warnings

need for consultation with the Water Corporation

need for independent engineering consultation

finding alternative locations or alignments where there are conflicts with buried

pipelines

These considerations will not all be relevant for every project. However ignoring them runs

the risk of causing expensive damage and project delays.

4.3 Do a damage risk assessment

A damage risk assessment should be conducted to assess the potential for interference to

any pipelines and other buried facilities.

General questions for a damage risk assessment

Will the site work … ? yes no not

sure

cause direct contact in any way with a pipeline (including any

relatively minor contact with the protective coating)

involve digging adjacent to or otherwise disturbing pipeline

foundations, bedding or other support

cause subsidence of a pipeline, supporting material or

structures

cause high loads to be applied directly to a pipeline or the soil

above it

result in high impacts, shock or vibration near or directly to a

pipeline

limit access to a pipeline or other assets for future works or


maintenance

cause electrical currents to be directly applied to or induced in

a pipeline

interfere with cathodic protection - either through direct

damage or affecting voltage potentials

Some work-related activities may impact pipelines even though the main construction

activities are not located near any pipelines. Factors such as location of site access tracks,

movement of heavy loads, location of laydown / storage areas, installation of soil anchors,

piledriving and blasting can damage pipes.

You may be required to notify us of your planned work so we can consider the risks. See

Section 5 - Notification of planned work

The technical or physical aspects which you must consider in the damage risk assessment

are described in Section 6.

4.4 About Water Corporation plans

What the Water Corporation will provide

The Water Corporation, via the Dial before You Dig service, will provide water, sewer and

drainage plans in a PDF format or by fax. PDF plans can be viewed on screen and printed at

the required size. When printing plans it is essential that they are printed sufficiently large

to show all details.

Additional plan information if required can be obtained from Water Corporation

Reprographics at John Tonkin Water Centre, Leederville, WA on 9420 2605. Charges

apply.

What the plans show

Water Corporation plans show the nominal or approximate horizontal location of most

buried water, sewerage and drainage facilities. Pipe depths are not shown. See indicative

depths of cover in Section 6.11.

Individual services to properties are not usually shown however their existence should be

assumed. Some properties such as hospitals may have more than one sewer or water

service to the property.

Only Water Corporation owned drains are shown on drainage plans. Other drains may

belong to local government or Main Roads WA. Information about these drains must be

requested from these agencies.


Private water or sewer mains also may not be shown.

Plans only provide an indication

The Water Corporation has taken due care in the preparation of plans but cannot guarantee

the accuracy of facility, cadastral, or other information provided. It is the responsibility of

the people conducting works to ensure pipelines will not be affected by their works.

Plans should never be relied on as the sole means of locating assets. Plans only provide an

indication of the existence of buried assets. For various reasons asset details or actual

location may differ from information shown on plans.

Errors in plans

If any errors or inaccuracies are found in plans please advise Spatial Information

Management Group on 9420 2068.

4.5 Documentation to be kept on site

Plans, DBYD information, work clearances and any other related information must be kept

on site at all times. This information must also be made available to alternative work crews

or new workers coming on site who need to know about buried pipes.

Regulation 3.21 of the Occupational Safety and Health Regulations (1996) requires that “an

accurate diagrammatic representation of the service that might be affected” is available on

site before the work commences where there is any risk that the work may interfere with

services.

4.6 Locating assets on site

All pipelines in the path of or adjacent to excavations must be positively identified. This

means they must be visibly confirmed by careful potholing prior to work.

Regulation 3.21 of the Occupational Safety and Health Regulations (1996) requires the

location of services to be established before work commences where there is any risk that

the excavation work may interfere with these services.

Buried pipelines can be located by various means. The starting point is to get Water

Corporation plans (and the plans from other asset owners) from DBYD. The plans will


provide an indication of water, sewerage or drainage assets in the vicinity of the planned

works.

Surface indicators

Visual indicators at the site may point to the existence of underground facilities. Typical

surface indicators are:

buildings

cathodic protection test points

electrical cabinets

inspection covers

manhole covers

pits

signs, markers, tags

valve covers

water sampling points

See some examples in Section 6.20.

Services for locating buried utilities

Independent locating services can be engaged to conduct site surveys and locate buried

pipelines. These services have various methods and tools for locating assets, such as

electronic detection and vacuum excavation equipment. Different contractors offer different

levels of service so contractors should be chosen carefully.

Location services are listed in the Yellow Pages® under “Underground Service Locaters”.

Assistance with asset location

The Water Corporation can assist with locating assets on site. Charges apply for this service.

Typically 5 days notice would be required to enable a site visit to be scheduled.

Contact 13 13 75.

4.7 Guidance for planners and project managers

This is a general guide if you work in the role of planner or project manager. Titles and roles

will vary among organisations. The points below should be adapted for your individual

circumstances.

1. Do not assume that asset protection should be solely the site contractor’s

responsibility. Some aspects are best addressed by the planner or project manager

during early project or job planning.

2. Consider the content of this guideline. Consider how it applies to your project and

how the various issues should be addressed.


3. Be aware of the potential risks associated with working around water pipelines and

plan accordingly. (See Section 3)

4. Plan the site work early – there may be some aspects which if not addressed early

may delay your project. Similarly, allow sufficient time in the project for site

workers, excavators etc. to adequately locate and protect assets if this is their

responsibility.

5. Consider conducting a site utilities survey using a specialist locator as part of early

project planning.

6. In some circumstances the Water Corporation should be notified of the planned work

so that damage risks can be assessed. (See Section 5)

7. Ensure that the site team, contractors, etc. are aware of pipeline damage prevention

requirements. Reinforce this by various means such as by providing clear

documentation, instructions, briefings, meetings, etc.

8. Ensure that all relevant documentation is passed on to the site team, and any

subsequent teams, and is retained on site.

9. Consult with the Water Corporation to clarify any aspects which are unclear.

10. Consider adopting checklists or other mechanisms as standard practice to assist with

planning or site work. (See example in Appendix.)

4.8 Guidance for site supervisors, excavators, site workers, machine

operators

This section is general guide if you work in the role of site supervisor or otherwise work on

site. This includes site supervisors, work teams and sub-contractors. Titles and roles will

vary among organisations. The points below should be adapted for your individual

circumstances.

For the purpose of this section it is assumed that site work is conducted on behalf of a

“client” who provides instructions via a planner or project manager, or someone in a similar

role, to the site-based team or supervisor.

1. Review and understand all information provided by the client, planners or project

managers as applicable. Consider whether sufficient attention has been brought to

pipeline location and protection. Do not assume that this has been adequately done

unless this is clearly evident from the work documentation provided.

2. If plans have not been obtained from Dial Before You Dig, it is essential that they be

obtained before any site work commences. It is also a legal requirement under OSH

legislation to have utilities plans available.

3. Be aware of the potential risks associated with working around water infrastructure

and ensure appropriate arrangements are in place. See Section 3.

4. Refer to this document for other considerations during the work.

5. Access to Water Corporation manholes is hazardous and is prohibited.

6. In some circumstances the Water Corporation must be notified of the planned work

so that damage risks can be assessed. See Section 5.

7. Ensure site staff are aware of pipeline locations, and the arrangements and work

methods to be used to ensure protection. This particularly applies to machine

operators.


8. Pipelines in the vicinity of the work must be positively located by potholing before

any mechanised equipment is used.

9. Where there is more than one team or a changeover in staff, ensure an appropriate

handover of information is provided to the next team so they are aware of the

pipelines and how to work around them.

10. Ensure all relevant documentation is retained on site.

11. Advise the Water Corporation of any errors in plans on 9420 2068.

4.9 Guidance for services locators

This section is general guide if you are a services locator. The general expectation of clients

is that buried services will be located thoroughly, and will be clearly marked and recorded to

enable the works to be conducted efficiently. The relevance of all of the following to a

particular job however will depend on the level of service agreed between the locator and

the customer. The points below should be adapted for your individual circumstances.

1. Be aware of the potential risks associated with working around water, wastewater

and drainage infrastructure and ensure appropriate arrangements are in place. See

Section 3.

2. Access to Water Corporation manholes is hazardous and is prohibited.

3. Obtain Water Corporation and other asset owners’ plans from Dial Before You Dig

before starting work.

4. In some circumstances the Water Corporation must be notified of the planned work

so that damage risks can be assessed. See Section 5.

5. Some pipe materials are non-metallic and materials may change multiple times over

a given distance.

6. Ensure that major fittings and other equipment associated with pipelines are also

clearly identified on plans and documentation. These fittings may project outwards

from a pipe or be found at different depths than the pipeline itself. Cathodic

protection equipment and cables may extend some considerable distance from the

pipeline they are protecting.

7. Ensure that facility markings:

8. are clear and enable the client to clearly distinguish between different buried

pipelines (and other facilities)

9. are suitably durable for the site conditions, the nature and duration of the customer’s

project

10. are adequately spaced so as to show accurate location especially where there are

changes in direction, curves, or where there are multiple facilities in the area

11. For large pipelines the width of the pipeline should be indicated as well as the centre-

line.

12. Ensure that written records:

13. clearly and accurately reflect the site markings

14. highlight any areas considered of greater risk such as congested areas, critical assets

or areas of uncertainty.

15. Conduct an appropriate handover to the client. This may involve provision of

documentation, one-on-one meetings and/or a site walk-through as appropriate.


16. Remind clients that they must observe appropriate practices during the works to

protect pipelines as described in this guideline.

17. Advise the Water Corporation of any errors found in plans on 9420 2068.


5 Notification of planned work

If you intend to excavate or do other ground disturbing work near Water Corporation

pipelines listed below it is strongly recommended that you notify the Water Corporation.

Contact 13 13 75 at least 5 working days prior to the work commencing to discuss your

plans with a technical advisor. The technical advisor may require a damage risk assessment.

This will usually be conducted in a face-to-face meeting at one of our offices depending on

the work location. In straight forward cases the assessment may be conducted over the

phone. This risk assessment will enable you to be better prepared to undertake the work

without causing damage. Works conducted completely outside of the zones indicated in the

Table 1 do not require a Water Corporation risk assessment.

Table 1 – When notification is required

Asset in the planned work area Size Contact Water Corporation if ground

disturbing work involves ...

Water main – all materials 300 mm

dia or

greater

working within 3 m of the pipe

centreline, or

crossing under or over a pipe

Water main - RC or AC All sizes working within 2 m of the pipe

centreline, or


Sewerage pressure main All sizes working within 3 m of the pipe

centreline, or


Drainage pressure main All sizes working within 3 m of the pipe

centreline, or


Any pressure pipes All sizes working near key infrastructure such

as railways, freeways, bridges or

similar

Extra caution required – be aware

that damaged pressure pipes can

undermine foundations and damage

key infrastructure.

Gravity sewers, junctions and

risers

All sizes For underground power installation:

crossing within 1 m of a pipe wall, or

excavating parallel within 0.5 m of a

pipe wall

Drainage pipe All sizes For underground power installation:

crossing within 1 m of a pipe wall, or

excavating parallel within 0.5 m of a

pipe wall

All above Very heavy vehicle crossings other than on

established (i.e. permanent) roadways.


Pipeline types, sizes and materials are indicated on Water Corporation plans. Many large

pipes are also labelled such as “Serpentine T.M.” (trunk main) or “Armagh St Sewer P.M.”

(pressure main).

Ground disturbing work - includes open trench or trenchless excavations, any ground

penetration deeper than

500 mm, and the use of vehicular compaction equipment (i.e. not hand operated

equipment).

Crossing - includes installation / construction by open trench or trenchless methods, and

installation of soil anchors.

RC- reinforced concrete

AC Asbestos cement

In most instances work conducted outside of these zones will have no impact on buried

pipelines. However some activities conducted outside of these zones may still cause

damage. Examples of these are the installation of earth anchors and piledriving.

In all situations you must still assess the risk of interference or damage associated with

your work. See also Sections 4 and 6.

If you have any doubts about the potential for your work to interfere with pipelines contact

the Water Corporation on 13 13 75.

Proceeding with the work

The Water Corporation will be satisfied for the work to proceed if:

a. the work will not interfere with pipelines and associated equipment

b. the work will not disrupt delivery of services

c. the work will not conflict with Water Corporation work

d. the party is aware of damage risks and work requirements

e. the party is aware of the potential risks associated with working near water

infrastructure

The Water Corporation may specify conditions to apply to the job. These conditions may

differ from requirements described in this document.

5.1 When must the Water Corporation be notified?

The Water Corporation should be notified between 5 and 15 working days before any

ground disturbing work is planned to commence in the circumstances listed in Table 1.

5.2 How to notify the Water Corporation

Contact 13 13 75 to arrange a damage risk assessment. The operator will direct you to the

appropriate operational area depending on the location of the planned work.


Relevant Water Corporation sewer, water or drainage plans must be obtained from DBYD

before discussing the work with the Water Corporation technical advisor.

The technical advisor will discuss the work with you usually by appointment at one of our

offices:

Canning Vale 273 Bannister Road, Canning Vale 6155

Balcatta 240 Balcatta Road, Balcatta 6021

Leederville 629 Newcastle Street, Leederville 6007

5.3 Damage risk assessment

A technical advisor will discuss the work plans with you to understand the nature of the

work and to identify any potential risks to Water Corporation pipelines. The advisor will

communicate to you any requirements or recommendations for avoiding damage or

interference.

The person attending the meeting must be the person with direct responsibility for site

works such as the site supervisor or digging contractor, not an office-based planner or

project manager.

Costs

The damage risk assessment is free. Charges will apply if any site works or other site

attendance is required by the Water Corporation.

Information required

The following information will be required for the risk assessment meeting:

relevant Water Corporation plans showing water, sewerage or other assets in the area

obtained via Dial Before You Dig (mandatory)

your site plans showing the intended work, excavations, planned routes, etc

drilling plan / method statement if directional drilling is planned

information on major activities to be conducted such as drilling or compaction (See the

technical areas in Section 6.)


6 Technical considerations for works near pipelines

This section provides information about the various physical or technical considerations

during work planning. It is presented in alphabetical order for easy reference.

6.1 Access

The Water Corporation requires access to pipelines at all times, including sewerage pressure

mains and pumping stations. Obstacles which prevent or limit access can significantly delay

a response in the event of an emergency.

Requirements

a. Heavy vehicles, construction materials and similar heavy materials, such as materials

in lay-down areas, must not be stored over pressure mains or block access to

pumping stations.

b. Storage of other lighter items is permitted if the materials can be readily relocated in

the event of an emergency.

6.2 Alignments

A pipeline alignment or route is usually expressed as a distance from a property or road

boundary.

The Water Corporation operates water, sewerage and drainage pipelines. Major pipelines

are usually installed in road reserves and public open space but may also be found in

private property.

Where possible pipelines and other facilities in road reserves follow standard alignments as

stated in the Utility Providers Code of Practice (available from Main Roads WA). However

there are often deviations from these standard alignments.

In pipe reserves and easements there are no fixed alignments.

Requirements

a. Where possible comply with the standard alignments and clearances for installation

of new facilities. If compliance is not possible contact the Water Corporation to

discuss alternative arrangements.

b. Verify the actual alignment of existing pipelines in the vicinity of the planned works

before commencing work.


6.3 Asset Protection Officers

Field-based Asset Protection Officers regularly patrol pipeline routes and monitor works near

key Water Corporation pipelines. They can provide general advice and assistance but cannot

provide detailed technical advice or asset locations.

6.4 Blasting

Blasting can directly or indirectly affect pipelines. The indirect impacts include settlement of

the surrounding soil which places loads on a pipe wall. The direct impact on the pipe is by

vibration from the blast. If the blast generates sufficient energy at the pipeline it can cause

cracking or spalling of the cement mortar lining of steel pipes, or cracking of vitreous clay or

asbestos cement pipes.

In general, it is the lower frequency vibration caused by blasting that is likely to damage

pipes.

A small explosive charge in an excavation adjacent to an existing pipe may not cause any

damage as the vibration will typically be of a high frequency and low energy. However a

large production blast at say a distance of 100 m could cause damage.

The potential for damage from blasting is dependent on:

pipe type and age

pipe installation details (type of backfill or above ground installation, etc)

soil type and condition

proximity of the blast

type of explosive used

maximum instantaneous charge fired during the blast

Requirements

a. The blast plan must include an engineering assessment of the impact of the blast on

nearby water infrastructure and include appropriate mitigating actions in the blast

design.

b. Blast vibration monitoring may be required.

6.5 Buildings, obstructions, or storage of materials over a main

Placement of structures, equipment (such as cranes) and storage of items over mains can:

cause excessive loads to be applied resulting in damage or a burst

prevent or delay access for maintenance, repairs or emergencies.


Requirements

Storage of materials, placement of equipment, and building of any structure must be no

closer than the distances in the table below unless the items can be readily re-located and

do not cause an excessive load.

Diameter of Water

Corporation pipeline

Minimum distance from

pipe centreline

Less than 300mm 3 m

300 mm or greater 5 m

See also Section 6.26.

6.6 Cathodic protection / electrical mitigation systems

Cathodic protection systems reduce pipeline corrosion on metallic pipes by the application of

an electrical current. Damage to cathodic protection systems, while having no obvious

immediate effect, may cause accelerated deterioration and early failure of a pipeline.

Cathodic protection and electrical mitigation systems have buried components

interconnected by electric cables. These may be located some distance from the pipeline

being protected.

Requirements

a. Identify and positively locate any buried cathodic protection components likely to be

affected by the work as part of the site survey.

6.7 Chemical discharges and spillages

Discharged chemicals including acids and hydrocarbons can damage a main or can

contaminate water supplies by being absorbed through some pipe wall materials.

Requirements

a. Spillage of chemicals on or near water Corporation assets must be avoided.

b. Spillages into main drains must be reported immediately to 13 13 75.

6.8 Clearances to adjacent assets

Maintaining adequate clearances (separation) distances to other services is essential:

to ensure adequate access for future maintenance, repairs or replacement

to reduce the risk of pipelines being impacted by other assets or works located

nearby


to reduce the risk of impacts on other parties’ infrastructure by Water Corporation

pipelines or associated works, for example, where a burst pipe may damage adjacent

bridge foundations or a communications cable.

Minimum clearances

Minimum clearances for crossings are given below or are as otherwise specified by the

Water Corporation.

Diameter of Water

Corporation pipeline

Minimum vertical

clearance for service

crossings

Less than 300mm At least 150 mm

300 mm or greater At least 300 mm

Greater clearances are required where services run parallel to Water Corporation mains.

Greater clearances may also be required in some situations to ensure greater protection or

to ensure adequate future access to the main.

6.9 Clearances to overhead structures

Overhead clearance (headroom) of at least 15 m from ground level over pipelines is

required to enable access for lifting equipment.

ground level

clearance service

service

clearanc

e

clearance

service

s pipe

ground level

insufficient

clearances

pipe

service

s

service

service

Fig 6.8 - Ensure sufficient clearances from water, sewerage and drainage

pipes


6.10 Damage to pipelines

Even minor damage to pipelines may have significant long term consequences.

Requirements

a. Any damage to Water Corporation pipelines or other facilities is to be immediately

reported to 13 13 75 (all hours).

b. Do not a repair or cover up the damage as the damage will require specialist repair.

6.11 Depth of cover

The soil cover over pipelines provides support and protects them from excessive loads and

damage. The actual depth of cover may vary over time if the ground levels change. The

following is a guide to expected depths of cover but actual depths may differ from these

values.

Type of pipeline Location Minimum

cover

Maximum

cover

Trunk, water distribution or drainage

pressure mains (i.e. 300 mm

diameter or greater)

In verge 750 mm 2 m

Under road 900 mm 2 m

Water reticulation mains (i.e. < 300

mm diameter)

In verge 600 mm 900 mm

Under road 600 mm 750 mm

Sewer pressure mains (any size) In verge 900 mm 2 m

Under road 1000 mm 2 m

Requirements

The depth of cover as found on site must not to be altered either by removal or placement

of material unless as agreed with the Water Corporation. Water Corporation may have

additional requirements depending on circumstances.

insufficient

cover

excessive

cover

Fig 6.11 - Soil cover over pipelines must not be altered.

pipe pipe

natural ground

level


6.12 Emergency works

Where emergency work is required to be carried out in close proximity to major Water

Corporation assets and pipelines, the Operations Centre is to be contacted on 13 13 75 (24

hours). Close liaison with Water Corporation operational staff must be maintained for the

duration of the work.

The Water Corporation requires unimpeded access to all water, sewer and drainage

pressure mains and main sewers in the event of having to undertake emergency work.

6.13 Excavations

An excavation is any operation in which earth, rock or other material in the ground is

moved, removed or otherwise displaced by means or use of any tools, equipment or

explosives and includes grading, trenching, digging, ditching, drilling, boring, augering,

tunnelling, scraping, cable or pipe ploughing and driving.

Excavations of all types can impact on pipelines. Machinery can:

crack or burst a pipe

damage a pipe’s protective coating

impose excessive loads

cause interior damage

cause subsidence

damage associated structures, equipment or fittings

damage electrical protection equipment.

The risk to pipelines increases with more extensive excavations and larger machinery.

Excavations which are long, deep, run parallel to a pipeline and / or have multiple crossings

will increase the risk of damage.

Requirements

Work planning, including excavation planning, must consider all the issues in this guideline.

6.14 Excavations - trenchless

Trenchless excavations cause minimal disturbance to soil and surface infrastructure such as

to road surfaces and pavements compared to open excavations. The use of trenchless

excavation methods has many advantages over more traditional excavations, however care

needs to be applied during planning.

Trenchless techniques often damage protective pipeline coatings and can result in major

damage. This damage, which may initially go undetected, may lead to subsequent service


disruption. It can also present significant hazards through the concurrent interference with

electrical or gas services.

When planning trenchless excavations the following should be considered:

the quantities, size and material of any nearby pipes

bore diameter

ground conditions

the accuracy and reliability of the technique or equipment being used

whether the excavation is parallel to or crossing any pipelines.

Also see Section 6.22 Soil anchors.

Requirements

a. Obtain plans from DBYD for the drill site.

b. Inspect the proposed drill site and establish the proposed drill path.

c. Check that locating equipment is operational over the proposed drill path and is not

affected by electrical interference or metal structures. If locating equipment is not

functional over the whole drill path an alternative means of verification will be

required such as potholing.

d. Potholing must be used to locate existing pipelines to ensure adequate clearances

are maintained and to locate other asset crossings. Expose all buried pipes that are

perpendicular or parallel within 1 meter of the drill path. Refer to Section 6.21 -

Potholing.

e. Where a pipeline crossing is required, the launch pit rather than the receive pit,

should be located nearest to the most significant pipeline if possible. See Figure 6.1

below.

f. The depth must be proven at pipeline crossing points.

g. Keep potholes open to monitor progress of the drill head near pipes and other

infrastructure and to ensure clearance distances are maintained.

h. Continuously monitor the path and depth of the drill head, including during

backreaming where the path of the drill head may deviate from the original path.

i. For works near important pipelines or for pipeline crossings the Water Corporation

must be notified. Refer to Section 5 above.

j. If the required clearances (separation distance) cannot be achieved the Water

Corporation must be consulted.


6.15 Exposing pipelines

Pipelines are installed in compacted bedding, selected fill and support material. This is part

of the pipeline design. The removal of soil adjacent to a pipeline may cause pipeline failure

by undermining this support. Even a small movement may have a significant impact.

Fig 6.15 – Excavating too close to a pipeline can undermine ground

support leading to failure

ground level

pipe movement due to

loss of soil support

excavation too close

to pipe

Fig 6.14 – Avoid damaging services when directional drilling

pothole launch pit receive pit

drill path

Locate the launch pit nearer to

pipelines than the receive pit to

reduce the risk of damage.

Establish pits which avoid

buried services and enables

drilling away from pipes, not

towards pipes.

drill

direction

Confirm the location and depth of

services by potholing.

Keep potholes open while drilling

(and backreaming) to visually

confirm clearances and prevent

damage.


Uncovering a main

In general pipelines must not be exposed. At least 500 mm cover must be maintained at all

times including during road box-out, unless approved otherwise.

Minimal exposure is acceptable such as for service crossings and if only the top of the

pipeline is exposed.

The Water Corporation must be contacted where:

a. a sewer pressure main is required to be exposed other than at a customer service

crossing

b. greater than 1 pipe length needs to be exposed (could be 2.4 m to 12 m depending

on the pipe type)

c. exposure is required for more than a couple of days

d. exposure is required to below the spring line height (i.e. mid height) of the pipeline

e. digging or tunnelling is required underneath a pipeline

f. digging or tunnelling is required parallel to a pipeline

Asbestos cement and vitreous clay pipes

Asbestos cement (AC) pipes are brittle and can be easily damaged if they are exposed or

the supporting soil is disturbed. AC pipes can also be damaged by compaction equipment.

Asbestos cement and vitreous clay (VC) pipes are assembled from short pipe lengths. Any

differential soil movement can damage these joints causing a leak or burst.

Water Corporation plans indicate pipeline material type.

Asbestos-wrapped pipe

Some pipelines have a protective wrap which contains asbestos. This asbestos does not

pose a health risk if this protective cover is not damaged or disturbed.

Protection of an exposed pipeline

If is necessary to expose a pipeline the following considerations must be observed:

a. excavators and other equipment working nearby are not to travel across or strike the

exposed main

b. loads are not to be placed on the pipeline including side loads from adjacent work

c. the pipeline bedding or side support is not to be excavated

d. the pipeline must not be exposed to chemicals or excessive heat

e. the pipeline is not to be left exposed any longer than necessary

f. the use of barricades, pipe support or ground support may be required.

Backfilling and reinstatement


Unsaturated soil

If the soil is not saturated the existing soil, free of any road base, rocks greater than 50 mm

or other foreign matter can be returned to the excavation to 200 mm cover above the pipe.

This shall be compacted by tamping to ensure no voids exist around the pipe. The

remaining volume shall be filled in 300 mm lifts with 4 to 6 passes with a small plate

compactor (e.g. 300 mm plate compactor) on each lift.

Saturated soil

It is preferred that the excavation is dewatered so that backfilling and compaction can be

done using unsaturated soil. Cement stabilisation will only be permitted when there is no

alternative.

If the soil surrounding the pipe is saturated, cement stabilised sand (sand:cement ratio no

stronger than 20:1 by volume) must be used to 200 mm above the pipe. This is to be

compacted by tamping to ensure there are no voids around the pipe. The remaining volume

is to be filled in 300 mm lifts with 4 to 6 passes with a small plate compactor on each lift.

Re-instate the surface as required by the local authority. Refer to Restoration and

Reinstatement Specification for Local Governments.

Water Corporation may require an inspection before back filling takes place and may require

compaction test results.

6.16 Mains on private property

Although main pipelines are usually located in road reserves and other crown land they also

may cross private property such is in rural or industrial areas. These are usually protected

by easements which have constraints on building activities.

Requirements

Landowners and those planning works on private land must be aware of any mains crossing

the land and must consider how their land use and other activities may impact pipelines.

Typical examples of activities which may impact pipelines are:

a. constructing a bore

b. building a structure such as a building, dam or water tank

c. removal of large trees

d. earthworks

e. installation of ground anchors

6.17 Manholes / access chambers

Access chambers (manholes) are located on some pipelines to enable access to a pipeline,

valve or associated equipment. They may assist your locations by indicating the location of

buried pipelines and other equipment. See also Section 6.19.


Warning: Accessing manholes is hazardous and is prohibited.

Fig 6.17 - Examples of access chambers

Requirements

a. Unauthorised access to manholes / access chambers is prohibited and is extremely

dangerous.

b. Where access is essential such as to confirm asset locations the Water Corporation

must be contacted.

c. Access chambers (and other assets) are not to be covered over or have materials

stored over them.

6.18 Marker tape and tracer wires

Buried marker tape, slabs or other similar warning indicators are not currently used by the

Water Corporation. Similarly, tracer wires are not used.

Many pipelines are wholly non-metallic or have non-metallic sections. These cannot be

detected by some electronic locating equipment and must be located by potholing.


6.19 Monitoring site works

The Water Corporation reserves the right to assign an officer to monitor site works which

may affect pipelines.

6.20 Pipeline fittings and structures

There are many different types fittings and structures associated with pipelines. These must

be protected from damage. These fittings and structures are essential for pipeline operation

and delivery of water services to the community. Common fittings and structures are:

anchor blocks

cathodic protection test points

electrical mitigation equipment

fire hydrants

flushing points

injection points

manholes

pits

sampling points

thrust blocks

valves

Some of these fittings will be identifiable by surface indicators and may be a useful aid

during planning as indicators of the location of pipelines – other fittings will be below ground

and will not be visible.

Buried fittings may be located at a different depths than the pipeline itself or can be offset

from the centre of the pipe. For example, some valves extend from the top of a pipe (e.g.

air valves) while others extend from the bottom (e.g. scour valves). Similarly manholes may

be offset from the centreline of the pipe.

The decision to relocate or modify a fitting due to works is at the discretion of the Water

Corporation. The developer or contractor will be liable for any costs incurred.

Examples of some of the fittings and surface indicators which may be found on site are

shown below.


Fig 6.20a - Cathodic

protection test point

Fig 6.20b – Fire service

standpipe

Fig 6.20c - Fire hydrant

cover

Fig 6.20d – Valve cover

(Metropolitan Water

Authority)


Fig 6.20e – Valve cover

(Metropolitan Water,

Sewerage, and Drainage)

Fig 6.20f – Trafficable

sewer cover

Fig 6.20g - Surface structures which indicate buried pipelines are in

the area

Requirements

a. Locate all pipelines and associated fittings.

b. Fittings and other equipment on a pipeline must be maintained in the condition in

which they are found and protected from damage during works.

c. Any damage must be reported to the Water Corporation on 13 13 75.

d. Normally exposed fittings shall not be covered over (including valve covers and

manholes)

e. Access to fittings and appurtenances is to be maintained 24/7 and not affected by

any other equipment or structure.

6.21 Potholing

Potholing is the technique of locating buried pipes by careful hand digging trial holes or by

the use of other “soft dig” techniques such as vacuum excavation.


Pipelines are not always at the locations depicted on plans. It is essential to pothole to

establish pipe location and depth. Potholing must be used before any machine excavation

commences.

Potholing is the only means of determining pipeline location with certainty and is used in

addition to, not instead of, electronic or other locating methods.

Potholing should be undertaken along the route of the proposed excavation to identify the

path of nearby pipelines (and other utilities) and their depth. The amount of potholing

required will depend on the risks, the excavation route and the density of assets in the area.

Pot-holing must be undertaken with reference to plans and other information provided by

the Water Corporation.

Requirements

a. The location of any pipelines and associated fittings in the vicinity of the planned

works must be verified by potholing.

b. In some locations the Water Corporation must be notified for a risk assessment

before potholing commences. See Section 5.

c. Where the installation of a service, whether by open excavation or trenchless

methods, crosses a pipeline each crossing point must be potholed.

d. For trenchless excavations the pothole must extend sufficiently deep to visually see

the boring tool just prior to it going over or underneath the pipeline. Minimum

clearances must be observed. Refer to Section 6.7.

e. For excavations parallel to a pipeline, pothole at 5 m intervals to verify location as

alignments can vary.

6.22 Power installations - poles

Power poles are large, have deep foundations and are under high loading from the power

lines.

Requirements

a. Power poles shall not be placed over Water Corporation pipelines.

b. Location of HV poles and towers require approval from the Water Corporation prior to

installation.

c. HV power transmission lines parallel to metallic pipelines must be checked against

AS/NZS4853:2000 Electrical Hazards on Metallic Pipelines, for risk assessment and

mitigation requirements.

d. Concrete blocks and stay wires are to be a minimum of 2 m away from any surface

of the pipe. Concrete blocks must have a surface area of no less than 1m2 facing the

main to disperse loads and stresses.


6.23 Power installations – directional drilling

Requirements

a. Directional drilling to install underground power which runs parallel to crosses any

gravity fed sewer or drainage pipes must maintain the following clearances:

parallel: 0.5 m

crossings: 1.0 m

b. If these clearances cannot be achieved the water Corporation must be contacted.

Refer to Section 5.

c. A CCTV inspection must be undertaken following this work.

6.24 Soil anchors

Soil anchors support retaining walls and basement sidewalls by using frictional restraint of

the soil in which they are placed. They are placed in soil before backfilling or are drilled,

concreted and then post-stressed. Soil anchors sometimes extend a significant distance

away from the construction area and can interfere with pipelines and other fittings.

Requirements

Soil anchors are not to be installed over Water Corporation services or rely on any soil in

the clearance zone around mains. Works planning must consider the full reach / extent of

the soil anchors and ensure that any pipelines in the vicinity are not affected.

ground

level

clearance

zone

soil

anchors

retaining wall

ground level

Fig 6.24 – Soil anchors must not extend into the pipeline clearance zone

pipe


6.25 Trees and vegetation

Care must be exercised in the selection and placement of trees, and the removal of trees

near major pipelines.

Some species have large and expansive root systems. Tree roots encroaching on a main

may exert damaging forces, may damage the protective coating or may constrain future

access to the pipeline for essential works. Smaller mains can burst as a result of tree growth

or movement such as during a storm. The risks depend on the type and size of tree and the

pipeline affected. Some pipelines are more susceptible to damage by trees than others.

Requirements

a. Plants that grow taller than 5 m are not to be planted within 6 m of a pipeline or in a

pipeline easement. Easements are usually identified on plans.

b. Planting or removal of trees or stump grinding in the vicinity of large mains requires

assessment by the Water Corporation.

c. Refer to Water Corporation brochure: Select the Right Tree. (While this document

refers to gravity sewer pipes it is also generally applicable to considering trees near

other water, sewerage or drainage pipes.)

6.26 Vehicles, access roads and tracks

Heavy vehicles crossing buried pipelines can cause damage due to heavy loads and

vibration. While the principal construction activities may be located at a safe distance from a

pipeline and have no direct impact, the route for heavy vehicles needs to be considered as

the movement of these vehicles across a main can cause damage. Site access roads must

also be considered in project planning.

Note: Even relatively light loads can crack pipes if the pipe is brittle with shallow cover.

Asbestos cement (AC) and cast iron (CI) pipes are particularly susceptible to damage from

loads.

Single or infrequent crossings may be acceptable but heavy loads will require an

engineering assessment.

Requirements

Heavy vehicles such as construction equipment or other heavy transport are not permitted

over pipelines without protective measures approved by Water Corporation.

Planning considerations:

a. Identify the buried pipelines within the site and near access ways to or from the site.

b. Assess the heavy vehicle access both entering or exiting a site and within a site

relative to buried pipelines.

http://www.watercorporation.com.au/_files/PublicationsRegister/11/Select_the_Right_Tree.pdf


c. Establish a clear signposted route into the site, and within the site, which does not

pass over buried pipelines.

d. Communicate the correct route to relevant parties such as by signposting or other

communications.

e. Use designated roads where possible.

f. If necessary construct a suitable access track (See table below.)

g. The access track must be maintained to avoid excessive vibration (e.g. potholes

repaired).

Pipeline diameter Access track requirements

Less than 300 mm 500 mm of limestone sub-base material to be laid above the

existing ground level.

300 mm or greater 1 m limestone minimum 4.5 m metre wide.

6.27 Vibratory compaction

The use of heavy vibratory compaction machinery in the vicinity of mains can cause damage

through:

damaging pipe joints

causing soil subsidence

cracking / disbonding of the internal cement lining of steel and ductile iron pipes

(which may cause corrosion and failure)

causing collapse of a main sewer

cracking brittle pipes such as concrete pipe

Requirements

a. The use of heavy vibratory rollers is not permitted within 5 m of the centre line of a

main unless otherwise approved.

b. Use of a light roller or 300 mm plate compacter working in layers of 300 mm is

permitted unless otherwise advised.

mortar lining in good

condition

damaged lining leading

to corrosion

Fig 6.27 – Vibrating rollers can crack the internal mortar lining due to excessive vibration


6.28 Warning markers and signs

In some locations, the Water Corporation has installed various signs or markers to indicate

the location of buried assets. These markers indicate approximate location only. Several

pipes may be indicated by only a single marker.

Fig 6.28 - Examples of signs and markers in use in some locations.


Requirements

a. Observe any markers, signs or tags in the area.

b. Markers are not to be removed unless necessary for the works. On completion of the

work Any markers removed must be replaced in their original location and

orientation.

c. Markers are to be protected from damage during works.

d. The Water Corporation may choose to install temporary warning markers during a

construction project. These markers are to remain in place until removed by the

Water Corporation.

7 Definitions

anchor block Large concrete block which anchors a pipeline to prevent

movement. See also thrust block.

cathodic

protection

Cathodic protection is means of controlling the corrosion of

metal surface by using the surface as the cathode of an

electrochemical cell. Cathodic protection systems are one

means of protecting pipelines from corrosion.

DBYD The Dial Before You Dig one call service.

interference Any activity or result of an activity which affects the integrity

of a Water Corporation asset or the ability of the Corporation

to operate or maintain the asset. Interference is usually, but

not necessarily some form of asset damage or disturbance.

infrastructure Refers primarily to buried pipelines and associated equipment,

such as valves and cathodic protection systems.

MWSS&D Act Metropolitan Water Supply, Sewerage and Drainage Act

OSH Occupational Safety and Health

pothole The activity of carefully digging exploratory holes by hand or

by using soft dig technology (vacuum extraction) to positively

verify the location of a buried asset without interfering with the

asset.

thrust block

A concrete block located at a bend, tee or end of a pipe which

resists the forces due to pressure and flow of water. The block

is cast against undisturbed soil. The soil adjacent to the thrust

block must not be disturbed as it is essential for resisting the

applied forces.

water

infrastructure

General term covering water, sewerage and drainage

infrastructure. (Also see infrastructure)


Appendix 1 – Applicable legislation

This section contains the relevant excerpts from various legislation which relate to

protection of assets.

1. Metropolitan Water Supply Sewerage and Drainage (MWSSD) Act 1909

2. Metropolitan Water Supply Sewerage and Drainage (MWSSD) By-laws 1981

3. Country Areas Water (CAWS) Supply Act 1947

4. Country Areas Water Supply (CAWS) By-laws 1957

5. Country Towns Sewerage (CTS) Act 1948

6. Country Towns Sewerage (CAWS) By-laws 1952

7. Metropolitan Water Authority Act 1982

8. Water Agencies (Powers) Act 1984

9. Occupational Safety and Health Regulations 1996

Note: Water legislation is currently undergoing a major review. New legislation is expected

in the next few years.

The information is provided in good faith for ease of reference. No warranty is given as to

the accuracy or completeness of this information. The Water Corporation disclaims liability,

whether in negligence or otherwise, for any loss or damage resulting from reliance on the

accuracy or completeness of this information. Reference should be made to source

documents available from the State Law Publisher as the definitive source.

METROPOLITAN WATER SUPPLY SEWERAGE AND DRAINAGE (MWSS&D) ACT 1909

50. Protection of fittings

(1) No person shall remove, alter, repair, renew, or uncover any pipe or other fitting which

is the property of the Corporation until the prescribed notice has been given to the

Corporation, and the consent of the Corporation in writing obtained.

50A. Construction over water mains prohibited without consent of Corporation

(1) A person shall not, without the prior consent of the Corporation, erect, construct or

place any building, wall, fence or obstruction in, upon, under or within the prescribed

proximity to a main or reticulation pipe of the Corporation used for the purposes of water

supply and then only upon and subject to such terms and conditions as the Corporation

thinks fit to impose for the protection of the pipe from interference or damage.

Penalty: $2000 and in the case of a continuing offence, a further penalty not exceeding

$200 for each day the offence continues after the Corporation serves notice of the offence

on the offender.

(2) The Corporation may demolish and remove any building, wall, fence or obstruction

which is erected, constructed or placed in contravention of subsection (1) and which

interferes with or injuriously affects a pipe in the supply of water, and perform any works

necessary for restoring or reinstating the pipe.


(3) In addition to any penalty that may be imposed on an offender under subsection (1) the

offender shall also pay to the Corporation the expense incurred by it in removing any

building, wall, fence or obstruction or in re-opening, restoring, repairing or reinstating a

pipe pursuant to subsection (2).

54. Penalty for destroying valves, etc.

If any person, not being authorised by the Corporation:

(a) wilfully or carelessly breaks, injures, opens or shuts, or wilfully permits to be broken,

injured, opened or shut, any lock, sluice, cock, valve, pipe, or other authorised fitting, or

any work belonging to the Corporation; or

(b) flushes or draws off the water from any waterworks of the Corporation; or

(c) does any other wilful act, or wilfully permits to be done any Act whereby such water is

wasted,

the person commits an offence.

Penalty: For an individual: $10 000. For a body corporate: $20 000.


66. Construction over sewers prohibited without prior consent of Corporation

(1) A person shall not, without the prior consent in writing of the Corporation —

(a) erect, construct or place any building, wall, fence or obstruction in, upon, over, under or

within the prescribed proximity to a sewer and then only upon and subject to such terms

and conditions as the Corporation thinks fit to impose for the protection of the sewer from

interference or damage; or

(b) obstruct, fill in, close up or divert a sewer.

Penalty: $2 000, and in the case of a continuing offence, a further penalty not exceeding


on the offender.



interferes with or injuriously affects a sewer in the carrying away of sewage, and perform

any works necessary for restoring or reinstating the sewer.

(3) In addition to any penalty that may be imposed on an offender under subsection (1),

the offender shall also pay to the Corporation the expense incurred by it in removing any


sewer pursuant to subsection (2).

69. Penalty for destroying sewers and fittings

Every person, who, not being authorised by the Corporation, wilfully or carelessly breaks,

injures, or opens, or permits to be broken, injured, or opened any sewer, property sewer, or

fitting, or any other work, shall for every such offence be liable to a penalty not exceeding:

(a) for an individual: $10 000; or

(b) for a body corporate: $20 000,

besides the amount of the expense to which the Corporation may be put in respect thereof

in repairing such sewer, property sewer, fitting, or work, and the amount of such expense

shall be recoverable as a debt in a court of competent jurisdiction.

158. Offenders may be arrested

Any officer of the Commission or the Corporation may, without warrant, arrest any person

found committing an offence against the Metropolitan Water Authority Act 1982 or this Act

or the by-laws if the offender refuses to give his name and address.

METROPOLITAN WATER SUPPLY SEWERAGE AND DRAINAGE BY-LAWS (MWSS&D)

1981

2.2 Protection of works

(2.2.2) No person shall wilfully or carelessly damage or cause damage to waterworks and

fittings which are the property of the Corporation.


(2.2.3) No person shall carry on, or cause to be carried on, any mining or quarrying

operation, or make any excavation of any sort, or cause any explosion or other action in the

vicinity of the Corporation's or the Commission's works which may cause damage or future

damage by subsidence of the ground, without the written permission of the Corporation or

the Commission as the case requires and under such conditions as the Corporation or the

Commission as the case requires may deem necessary.

(2.2.5) No person shall drive, take, ride or permit any vehicle, conveyance or animal to

cross any exposed pipe, valve, fitting or apparatus except at crossing points approved by

the Corporation or the Commission and indicated by sign-boards.

(2.2.6) No person shall drive, take or ride any vehicle, conveyance or animal across

underground pipelines or works, where warning signs have been erected by the Corporation

or the Commission except at crossing points approved by the Corporation or the

Commission and indicated by sign-boards.

2.3 Protection of grounds

(2.3.1) No person shall wilfully or carelessly injure, damage, disfigure, displace, or remove

any fence, stake, post, pillar, pipe, survey mark, peg, tablet or notice board belonging to, or

installed by the Corporation or the Commission.

(2.3.2) No person shall wilfully or carelessly injure, deface or disfigure any notice or copy of

a by-law, rule or regulation displayed upon any tablet or notice board erected by the

Corporation or the Commission.

(2.3.3) No unauthorised person shall open any gate, slip rail, manhole, door, or other

entrance into, or trespass upon any enclosure of the Corporation’s or the Commission’s

property without the written permission of the Corporation or the Commission as the case

requires.

(2.3.4) No unauthorised person shall stand, park or leave unattended any vehicle, trailer or

item of mobile equipment on property, (including depots) or reserves vested in the

Corporation or the Commission except in a place set aside and designated as a Visitors Car

Park.


COUNTRY AREAS WATER SUPPLY (CAWS) ACT 1947

43. Protection of fittings

(1) No person shall remove, alter, repair, renew or uncover any pipe or other fitting which is

the property of the Corporation until the prescribed notice has been given to the

Corporation and the consent of the Corporation in writing has been obtained.

43B. Construction over water mains prohibited without consent of Corporation

(1) A person shall not, without the prior consent of the Corporation, erect, construct or

place any building, wall, fence or obstruction in, upon, under or within the prescribed

proximity to a main or reticulation pipe of the Corporation used for the purposes of water

supply and then only upon and subject to such terms and conditions as the Corporation

thinks fit to impose for the protection of the pipe from interference or damage.

Penalty: $2 000 and in the case of a continuing offence, a further penalty not exceeding


on the offender.



interferes with or injuriously affects a pipe in the supply of water and perform any works

necessary for restoring or reinstating the pipe.

(3) In addition to any penalty that may be imposed on an offender under subsection (1) the

offender shall also pay to the Corporation the expense incurred by it in removing any


pipe pursuant to subsection (2).

45. Penalty for using unauthorised, and failing to repair, fittings

(1) Any person who:

(c) not being authorised by the Corporation:

(i) wilfully or carelessly breaks, injures, opens or shuts or wilfully permits or suffers to be

broken, injured, open or shut, any lock, sluice, cock, valve, meter, pipe or other authorised

fitting or any work belonging to the Corporation; or

(ii) flushes or draws off water from any water works of the Corporation; or

(iii) does any other wilful act, or permits or suffers to be done any act whereby the water is

wasted;

Penalty: For an individual: $10 000.

For a body corporate: $20 000.

112. Obstructing Minister or the Corporation or officers in performance of duty

Every person who obstructs the Minister or the Corporation, any officer of the Department

or the Corporation or any person authorised by the Minister or the Corporation in the

performance of any act or thing which the Minister or the Corporation, that officer or that

person is authorised or required to do in the execution of this Act or any regulation or

by-law made for the purposes of this Act shall be guilty of an offence. Penalty: $5 000.


114. Offender may be arrested

Any officer of the Department authorised by the Minister for the purposes of this section

may without warrant apprehend any person found committing an offence against this Act or

any regulation or by-law made for the purposes of this Act if the offender refuses to give his

name and address.

COUNTRY AREAS WATER SUPPLY (CAWS) BY-LAWS 1957

45. Pipelines, protection of

Vehicles, conveyances, or animals shall not be driven, taken, or ridden in such a manner as

to endanger the main conduit or any branch thereof, or be permitted to cross the same

except where crossing places have been provided as indicated by signboards.

46. Works etc., protection of

No person shall in the vicinity of any works carry on or cause to be carried on any mining or

quarrying operation, or make any excavation of any sort, or cause any explosion so as to

injure any waterworks, sewerage works, sewers, drains, pipes or fittings whatsoever.

67. Obstruction of pipes, sewers, drains or fittings

(1) Any person who without the written consent of the Corporation places or keeps any

material or thing or causes any material or thing to be placed or kept over any pipe, sewer,

drain or fitting which is the property of the Corporation, and thereby —

(a) trespasses on or causes injuries to such pipe, sewer, drain or fitting; or

(b) prevents or in any way impedes or obstructs the inspection, maintenance cleansing,

repair, management or use of such pipe, sewer, drain or fitting, shall be guilty of an offence

against these by-laws and be punishable on summary conviction by a penalty not exceeding

$40, and in the case of a continuing breach of this by-law the offender shall be liable to a

further penalty not exceeding $10 for each day the offence continues after notice thereof

has been given by or on behalf of the Corporation to the offender.

(2) The Corporation may cause any material or thing placed or kept over any pipe, sewer,

drain or fitting contrary to sub-bylaw (1) to be removed or otherwise dealt with as it thinks

fit.

COUNTRY TOWNS SEWERAGE (CTS) ACT 1948

34. Penalty for destroying valves, etc.

If any person, not being authorised by the Corporation:

(a) wilfully or carelessly breaks, injures or opens, or wilfully permits to be broken, injured or

opened any sewer, property sewer, fixture or fittings, or any other work; or

(b) diverts or draws off the sewage from any works of the Corporation,

he shall be liable to a penalty not exceeding:

(c) for an individual: $10 000; or

(d) for a body corporate: $20 000,


and shall, in addition, be liable to pay to the Corporation any damage sustained in respect

thereof in repairing the sewer, property sewer, fixtures, fittings or other parts of the works;

and the amount of such damage shall be recoverable as a debt in a court of competent

jurisdiction.

42. No construction over sewers except by consent

(1) No person shall erect, construct or place any building, wall, fence or obstruction in,

upon, over, under or within the prescribed proximity to any sewer without the previous

consent in writing of the Corporation, and then only upon and subject to such terms and

conditions as the Corporation may think fit to impose for the protection of the sewer from

interference or damage.

(2) Subject to subsection (1), every person who shall erect, construct, or place any building,

wall, fence, or obstruction in, upon, over, under or within the prescribed proximity to any

sewer, so as to interfere with or injuriously affect such sewer in the carrying away of

sewerage, and every person who shall obstruct, fill in, close up, or divert any sewer without

the previous consent, in writing, of the Corporation, shall, in addition to any other penalty

to which he may be liable, be liable to a penalty not exceeding $2 000 for every such

offence, and in case of a continuing offence, a further penalty not exceeding $200 for each

day after notice shall have been given by the Corporation to such person.

(3) Subject to subsection (1), the Corporation may demolish and remove any such building,

wall, fence, or obstruction, and perform any works necessary for restoring or reinstating

such sewers; and the person erecting such building, wall, fence, or causing such

obstruction, or obstructing, filling in, closing up, or diverting such sewer, as the case may

be, shall also pay the expense of removing such building, wall, fence, or obstruction, or of

re-opening, restoring, repairing, or reinstating such sewer.

COUNTRY TOWNS SEWERAGE (CTS) BY-LAWS 1952

8. Protection of works from injury

No person shall in the vicinity of any works carry on or cause to be carried on any mining or

quarrying operation, or make any excavation of any sort, or cause any explosion so as to

injure any waterworks, sewerage works, sewers, drains, pipes, or fittings whatsoever.

231. Obstruction of pipes, sewers, drains, or fittings

(1) Any person who, without the written consent of the Corporation places or keeps any

material or thing or causes any material or thing to be placed or kept over any pipe, sewer,

drain or fitting whether the property of the Corporation or otherwise and thereby —

(a) trespasses on or causes injuries to such pipe, sewer, drain or fitting; or

(b) prevents or in any way impedes or obstructs the inspection, maintenance, cleansing,

repair, management or use, of such pipe, sewer, drain or fitting, shall be guilty of an

offence and be punishable on summary conviction by a penalty not exceeding $40, and in

the case of a continuing breach of this by-law the offender shall be liable to a further

penalty not exceeding $10 for each day the offence continues after notice thereof has been

given by or on behalf of the Corporation to the offender.


(2) The Corporation may cause any material or thing placed or kept over any pipe, sewer,

drain or fitting contrary to sub-bylaw (1) to be removed or otherwise dealt with as it thinks

fit.

(4) This by-law applies irrespective of whether the material or thing concerned was placed

over a pipe, sewer, drain, or fitting before or after this by-law came into force.

232. Penalties

(1) Any person committing a breach of any of the provisions of these by-laws, to which no

specific penalty is attached, shall be liable on summary conviction to a penalty not

exceeding $200.

(2) In the case of a continuing breach the offender shall be liable in addition to the fine and

payment of expenses to a daily penalty not exceeding $50 for each day the breach

continues after notice thereof has been given by or on behalf of the Corporation to the

offender.

(3) In addition to any penalty provided by these by-laws, any expense, loss or damage

incurred by the Corporation or the Commission in consequence of the breach of any by-law

shall be payable by the person committing the breach and may be recovered as a debt due

in a court of competent jurisdiction.

METROPOLITAN WATER AUTHORITY ACT 1982

101. Offences

(1) A person shall not, without the prior consent in writing of the Corporation —

(a) erect, construct or place any building, wall, fence, structure or obstruction upon, over,

under or within the prescribed proximity to, a main drain otherwise than in accordance with

such terms and conditions as the Corporation may have imposed for the protection of the

main drain from interference or damage; (b) stop, obstruct, alter, damage, or interfere

with, a main drain; (c) cause or permit any sediment, noisome thing or pollutant to enter a

main drain; or

(d) cause or permit water to be taken from a main drain. Penalty: $1 000 and if the offence

is a continuing one a further $100 for each day or part of a day during which the offence

has continued.

(2) The Corporation may demolish and remove any building, wall, fence, structure or

obstruction which is erected, constructed or placed in contravention of subsection (1) and

which interferes

with or injuriously affects a main drain and perform any works necessary for restoring or

reinstating the main drain.

(3) In addition to any penalty that may be imposed on an offender under subsection (1),

the offender shall also pay to the Corporation any expense incurred by or on behalf of the


Corporation in removing any building, wall, fence, structure or obstruction or in reopening,

restoring, repairing or reinstating a main drain pursuant to subsection (2).

WATER AGENCIES (POWERS) ACT 1984

99. Street levels and widths

(2) A local government or department having the control and management of any street

shall give the Corporation at least 10 clear days notice in writing of its intention to change

the level, width or surfacing of any street in which any works of the Corporation have been

placed.

OCCUPATIONAL SAFETY AND HEALTH REGULATIONS 1996

3.1. Identification of hazards, and assessing and addressing risks, at workplaces

A person who, at a workplace, is an employer, the main contractor, a self-employed person,

a person having control of the workplace or a person having control of access to the

workplace must, as far as practicable —

(a) identify each hazard to which a person at the workplace is likely to be exposed

(b) assess the risk of injury or harm to a person resulting from each hazard, if any,

identified under paragraph (a); and

(c) consider the means by which the risk may be reduced.

3.21. Drawings showing location of certain services

(1) If there is a risk that work to be conducted at a workplace might interfere with any gas,

water, sewerage or electrical service then a person who, at the workplace, is an employer,

the main contractor, a self-employed person or a person having control of the workplace

must ensure that —

(a) the location of the service that might be affected is established; and

(b) an accurate diagrammatic representation of the service that might be affected is

available at the workplace before the work commences.


Appendix 2 – Useful pipeline protection planning checklist

This generic planning checklist is provided to help with project or job planning. This

checklist indicates the typical issues which should be considered during any project. It

relates to planning for Water Corporation asset protection only. There are many other items

which could be included. This list may be useful as is, but it is recommended that it be

adapted as required to suit the needs of individual organisations and circumstances.

Define the work area / boundary

Request plans from DBYD (This will identify Water Corporation and other DBYD

members’ plans but not necessarily all buried infrastructure owners.)

Request plans from other asset owners if applicable (i.e. Non-DBYD members)

Receive all asset owners’ plans

Review and understand all plans

Determine relevance of plans to the planned work

Seek additional information or clarification from Water Corporation if necessary

Conduct a damage risk assessment (Refer to these guidelines)

Create (or modify) work plans based on the damage risk assessment

Determine the need to engage a services locater to conduct a detailed utilities

survey

Determine the need to contact the Water Corporation for a damage risk

assessment

If so, schedule a damage risk assessment meeting. (This must be attended by

the person with direct site control.)

Plan / select appropriate excavation methods, work methods, controls and other

activities (including potholing)

Establish arrangements for site marking and protection of assets (e.g. signs,

bunting barricades)

Ensure site-related information and plans are current (especially if there is a

delay between planning and construction)

Ensure site-related information and plans are available for site crews

Select appropriate excavation or construction equipment

Plan a briefing for site crews addressing the following typical items:

pipeline locations

damage risks and mitigation actions

work methods to be used / modified (e.g. compaction methods, potholing)

compliance, control requirements (e.g. excavation spotter)

site information pack (DBYD, utilities plans, permits, etc.)

arrangements for handover to alternative crews


other

Conduct the briefing

Review any asset protection issues which appear during the project for

improvements to project procedures


Appendix 3 – References

1. Code of Practice Excavation, WA Government, 2005

2. Occupational Safety and Health Regulations (1996)

3. Restoration and Reinstatement Specification for Local Governments, Institute of

Public Works Engineering (IPWEA)

4. Utility Providers Code of Practice, Main Roads Western Australia

5. AS/NZS4853:2000 Electrical Hazards on Metallic Pipelines

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