Guidelines for the completion of pipeline works authorisations (PWA's)


Section 1 Need for guidelines

Section 2 Definitions

Section 3 Action required by companies Section 4 Summary of DTI process

Appendix A Application Checklist

Appendix B Consent to deposit materials on the seabed (Depcon)

Appendix C Consent for the discharge of the contents of a pipeline into the sea

Appendix D Useful addresses

1. Need for guidelines

Since the Guidance Notes for Petroleum and Submarine Pipelines were published in 1992 there have been some legislative changes. The Pipeline Safety Regulations 1996 were introduced by the Health and Safety Executive; as part of a consolidation exercise, the Petroleum Act 1998 repealed and replaced the Petroleum and Submarine Pipelines Act 1975 and the Offshore Petroleum Production and Pipelines (Assessment of Environmental Effects) Regulations came into effect in 1999. All have had an impact in the process of making an application for an offshore Pipeline Works Authorisation (PWA).

Please note that a Pipeline Works Authorisation should have been issued before construction of a pipeline or pipeline system begins. It is recommended that, before submitting an application, the prospective owner should informally consult both Pipelines Administration in DTI and the Health and Safety Executive at the earliest possible opportunity, to discuss the proposed scheme and the regulatory requirements involved. (For addresses and telephone numbers please see Appendix D).

Where there are no objections it takes approximately four months from receipt of the application to issuing the authorisation. In the case of pipelines in respect of which an environmental statement is required under the Offshore Petroleum Production and Pipelines (Assessment of Environmental Effects) Regulations 1999, the procedure may take longer in order for all the environmental issues to be properly considered. Further guidance on the effect of the 1999 Regulations can be found in the Environment section of this web site. Operators are therefore urged to submit their applications in good time to meet their deadlines.

2. Definitions

Offshore Pipeline

Under the Petroleum Act 1998 an authorisation is required for the construction and/or use of a "pipeline" in controlled waters.

A pipeline is defined as a pipe or system of pipes "for the conveyance of any thing, together with any apparatus and works associated with such a pipe or system". This includes pipelines used for the conveyance of hydrocarbons, water and chemicals. However, although other consents may be required for their construction/use, electric cables, drains and sewers are not pipelines under the 1998 Act, nor are hydraulic control lines or umbilicals of hydraulic controls.

Controlled waters means the UK territorial sea and any part of the sea on the UK continental shelf.

Holder of the PWA

The holder is the person to whom the authorisation is issued. An authorisation may not be issued to a person other than a body corporate.

The Users of a Pipeline

The users are the persons authorised by the PWA to use the pipeline for the purpose of conveying any fluid so authorised.

The Operator of a Pipeline

The operator is the person designated by the holder to be responsible for organising or supervising the construction or operation of the authorised pipeline in a manner which complies with the authorisation and, inter alia, with any relevant legislation existing at the material time. The works authorisation may name the operator as the holder.

Owner of the Pipeline

DTI requests details of the owner(s) in the application and in future these will be listed in the PWA. The Petroleum Act 1998 allows the Secretary of State to make an order, designating a person as the "owner" of a pipeline, after giving the person concerned an opportunity of being heard on the subject.

Pipeline Works Authorisation (PWA)

Under the Petroleum Act 1998 a "works authorisation" means an authorisation:

a. for the works for the construction of a pipeline;

b. for such works and for the use of the pipeline.

Deposit of Materials on the Seabed Consent (DEPCON)

Required before any materials e.g. rocks/ mattresses are placed on the seabed during construction of a pipeline or in order to maintain such a pipeline. (Full details Appendix B.)

Consent for Discharge of the contents of a Pipeline into the Sea (DISCON)

Required before a line is filled with chemicals or before any discharge (other than untreated seawater or sweet water) takes place. (Full details in Appendix C.)

3. Action required by companies

4. Summary of DTI process

Appendix A

Application Checklist


Administrative Detail



Technical Details


18 copies of the above are required (19 if the project is within Territorial Waters). Three copies of the Navigational Charts must be in colour.

Appendix B

Consent to deposit materials on the seabed (Depcon)

The permanent placing or deposition of materials such as gravel, rock, mattresses or protective pipeline covers on the seabed during the construction of a pipeline is governed by the Pipeline Works Authorisation. Schedule 2 of the authorisation prohibits any further deposition except with the prior written consent of the Secretary of State.

For pipelines which do not have a PWA, for example, pipelines constructed prior to the coming into force of the Petroleum and Submarine Pipelines Act 1975, any deposition would require a licence under the Food and Environmental Protection Act 1985 (FEPA). (Part II of FEPA only exempts from its provisions anything done "for the purpose of constructing or maintaining a pipeline as respects any part of which an authorisation is in force".)

FEPA is administered by the Ministry of Agriculture, Fisheries and Food (MAFF) as regards England and Wales, by the Scottish Executive Marine Laboratory on behalf of the DTI as regards Scotland and by the Department of Agriculture for Northern Ireland (DANI) as regards Northern Ireland. Applications for licences under FEPA should be made direct to the relevant Department.

Applications for consent to deposit materials under a PWA should be made to Offshore Pipelines

Administration at the DTI and copied to Health and Safety Executive on Form Depcon1. Where appropriate (simple) drawings showing where, for example, mattresses are to be placed, should accompany the form.

The information required by the form includes -

i. a description of the material to be deposited
ii. the quantity to be deposited
iii. in the case of rocks, the maximum size to be deposited
iv. the location of the proposed site.

In addition, the following further details are required -

When a consent for a deposition of materials is given, it usually contains terms reserving to the Secretary of State the right to require removal of any materials deposited should they become a potential or actual hazard or obstruction to other seabed users. Removal may also be required at the end of the useful life of the pipeline.

The pipeline owner should consult relevant fishing organisations and other seabed users before any operation to deposit materials is begun and keep appropriate Government Departments advised of agreements reached. (This is usually covered in discussion with the fishermen about the pipeline project as a whole).

Please note that if any preparatory work, for example pipeline crossings, are to be put in place prior to the construction of the pipeline, the PWA should be requested early enough to undertake this work, otherwise a FEPA licence may be required. As stated above, it is only activities "for the purpose of constructing or maintaining a pipeline as respects any part of which an authorisation is in force" which are exempt from the provisions of FEPA.

Sample Depcon 1


Details for Deposit Consent: Form DepCon 1

Col 1 Col 2 Col 3 Col 4 Col 5 Col 6 Col 7
Pipeline Number Proposed Date
(month and year)
Type & Size of Materials Quantity Location of Deposit Drawing Number
(if applicable)
        From: To:  

Appendix C

Consent for the discharge of the contents of a pipeline into the sea.

The discharge from a pipeline of substances, excluding untreated sea water or sweet water (but including untreated sea water or sweet water which may contain unquantified amounts of mill -scale or rust), into any waters in or around the United Kingdom is prohibited without an appropriate consent or licence.

The specific consent requirements in respect of discharges from a pipeline into the sea depend upon whether the pipeline in question is the subject of a Pipeline Works Authorisation. The position is as follows:

a. for pipelines built prior to the coming into force of the Petroleum and Submarine Pipelines Act 1975
(i.e. where no authorisation exists) discharges are subject to the Food and Environment Protection Act 1985 (FEPA) and would require a licence under that Act. (FEPA is administered by MAFF for discharges in English and Welsh waters, by SERAD - Marine Laboratory on behalf of the DTI in Scottish waters and by DANI for discharges in Northern Ireland waters)

b. pipelines which have a Pipeline Works Authorisation are exempt from the requirements of FEPA.

However, under the terms of the works authorisation, the prior written consent of the Secretary of State is necessary before a discharge can take place and an application for that consent should be made on Form DisCon1 to Pipelines Administration at the DTI.

In both cases, in determining whether to allow the operational discharge of pipeline substances into controlled waters regard would be given to the need:

i. to protect the marine environment, the living resources which it supports and human health;
and ii. to prevent interference with other legitimate users of the sea.

Notification of line fill and discharge

To hasten the process of issuing a discharge consent, prior notification of intended line fill should be given in all cases to Environmental Section at the DTI and the Health and Safety Executive, also to MAFF, SERAD, Marine Laboratory or DANI as appropriate.

[A minimum of three weeks notice should be given. It is advisable that notification takes place as early as possible, as recommendations may include advice on the use of alternative, less toxic, chemicals. An additional time allowance should be made for the processing of discharge consents for discharges near median lines and at borderlines between MAFF/SERAD and DANI.]

Particular attention is drawn to the prior notification which should be given in all cases of line fill involving radioactive substances, as subsequent discharges may also be subject to the Radioactive Substances Act 1993.

The procedure for obtaining a discharge consent under a PWA is set out below.

Details required:

i. the nature and chemical composition of the substance, including the trade name of the product and the name of the company distributing the product,

ii. the date on which it is proposed to discharge the substance

iii. the quantity, in cubic metres, of the substance it is proposed to discharge,

iv. the maximum rate, in cubic metres per hour, at which it is proposed to discharge the substance

v. the geographic co-ordinates, and height or depth in metres from the lowest astronomical tide (LAT), or the place at which it is proposed to discharge the substance,

vi. the total depth of water, in metres from LAT, at the point of discharge and particulars of the point and manner of discharge,

vii. the respective concentration of each of the chemicals, in parts per million, contained in the substance which it is proposed to discharge,

viii. the toxicity of each such chemical to marine organisms, or the toxicity of the total content of the substance or both,

ix. safety procedures for handling and storage, including line fill and discharge,

x. particulars of any means of dispersal,

xi. and such other information as may be requested.

Proposed concentrations and total diluted quantities in particular should be notified, as they affect the acceptability of the line fill proposals and, in turn, the operational discharge.

Method of discharge

In considering a schedule for discharges, the following points should be noted:

a. near-surface discharges from unmodified outlets at platforms should normally be by cascade over the platform structure to the sea surface;

b. mid -water discharges from platforms are preferable and should normally be made by means of at least two horizontally directed sub-sea nozzles;

c. horizontal discharges from submarine pipelines on the seabed should normally be avoided; pipe ends should be directed upward and have at least two nozzles;

d. if the proposed discharge lies in an environmentally sensitive area, for example, in a fish breeding or nursery area, it may be necessary for MAFF, SERAD or DANI to stipulate either no discharge within certain times of the year, or especially stringent conditions to ensure maximum and effective dilution.

Standard restrictions

The following considerations should be taken into account at all times:

a. Toxicity measurement
When the toxicity is likely to be high or the concentrations of discharged substances above normal, there may be a requirement for samples to be taken and analysed to demonstrate the speed and efficiency of dispersal.

b. Fluorescent indicators
Fluorescent indicators should not generally be used in concentrations greater than 15 ppm, or as approved by MAFF, DTI and DANI in specific areas.
Consents for discharges containing fluorescent indicators would normally require that the local MAFF/ SERAD - Marine Laboratory/ or DANI District Inspector be notified immediately before the discharge.

c. Manufacture of domestic water from seawater
It is strongly recommended that the operators of all equipment for the manufacture of domestic water from seawater within 1 kilometre of the point of discharge are advised to shut down during a pipeline discharge and for a suitable period thereafter which should not be less than twenty- four hours.


In certain cases, a condition of the consent to discharge may be that samples of seawater are taken at specific locations near the point of discharge. In these cases, operators would be instructed to employ an independent body approved by MAFF/SERAD Marine Laboratory or DANI as appropriate for collection and analysis of the samples and to submit the results to them.

Sample form DisCon 1


Details for Discharge Consent: Form DisCon 1

Col 1 Col 2 Col 3 Col 4 Col 5 Col 6 Col 7 Col 8 Col 9 Col 10
Pipeline Number Length (m) Event Anticipated Date of Discharge Discharge Location
(with Geographic
Discharge Depth (m) Volume of Discharge
(m3 / hr)
Discharge Rate
(m3 / hr)
Chemicals to be Discharged Concentration of Chemicals (ppm)

Appendix D

Useful addresses

Applications to:

Department of Trade and Industry
The Secretary of State
Department of Trade and Industry
Oil & Gas Office
4th Floor, Atholl House
86-88 Guild Street
AB11 6AR

Marked for the attention of your nominated contact.

Telephone: 01224 254055
Facsimile: 01224 254019
Tel Enquiries
Pipeline Policy - Louise Novell
Tel: 01224 254052
Fax: 01224 254089
Pipeline General Enquiries - Jacqui Adshead
Tel: 01224 254057
Fax: 01224 254089
Pipeline Discharge Consents - Julie Duguid
Tel: 01224 254045
Fax: 01224 254019
Food Environment Protection Act (FEPA):
General Enquiries - Elaine McLaughlin
Tel: 01224 254012
Fax: 01224 254019
Pipeline Decommissioning - Ian Furneaux
Tel: 01224 254021
Fax: 01224 254018
Enquiries regarding PON XV's to - Elaine McLaughlin
Tel: 01224 254012
Fax: 01224 254019
Other government departments:
Health and Safety Executive
Chemical & Hazardous Installations Division
(Scottish Waters)
Lord Cullen House
Fraser Place
Aberdeen AB23 3UB

Contact: Tim Ingram
Tel: 01224 252623
Fax: 01224 252555

Health and Safety Executive
Chemical & Hazardous Installations Division
(English Waters)
122A Thorpe Road
Norfolk NR1 1RN

Contact: Peter Runagall
Tel: 01603 828000
Fax: 01603 828050

Department of Environment, Food and Rural Affairs Environmental Protection Division
Marine Resources & Licensing Branch
Nobel House
17 Smith Square
London SW1P 3JR

Contact: John Harte
Tel: 020 7238 5330
Fax: 020 7238 5724

Department of Environment, Food and Rural Affairs Centre for Environment, Fisheries and Aquaculture Science
Fisheries Laboratory
Remembrance Avenue
Burnham on Crouch
Essex CM0 8HA

Contact: Richard Rycroft
Tel: 01621 787200
Fax: 01621 784989

Department of Transport, Local Government and the Regions Ports Division
Room 1/27
Great Minster House
76 Marsham Street
London SW1P 4DR

Contact: Damion Bagalue
Tel: 020 7890 5098
Fax: 020 7676 2188

Scottish Executive Environment and Rural Affairs Dept. Marine Environment Branch
Pentland House
47 Robb's Loan
Edinburgh EH14 1TY

Contact: Lynn Taylor
Tel: 0131 244 6234
Fax: 0131 244 6313

Scottish Executive Environment and Rural Affairs Dept. Marine Laboratory
PO Box 101
Victoria Road
Aberdeen AB9 8DB

Contact: Derek Saward
Tel: 01224 876544
Fax: 01224 295524

Department of Agriculture and Rural Development for Northern Ireland Fisheries Division
Annexe 5
Castle Grounds
Stormont Belfast

Contact: Damien Skillen
Tel: 02890 522365
Fax: 02890 522394

Department of the Environment for Northern Ireland Environment and Heritage Service, Quality Water Unit
Calvert House
23 Castle Place
Belfast BT1 1FY

Tel: 01232 540540

The Welsh Office New Crown Building
Cathay Park
Cardiff CF10 3NQ

Tel: 029 2082 5111

Ministry of Defence Mapping and Charting Officer
Office of the Flag Officer Submarines
Eastbury Park
Middlesex HA6 3HP

Contact: Colin Bullimore
Tel: 01923 838224

Fax: 01923 846392
Ministry of Defence (Navy) Hydrographic Office
Nautical Chart Branch 1(c)
 Somerset TA1 2DM

Contact: Helen Goodey
Tel: 01823 337900
Fax: 01823 284077

The Crown Estate
(English Waters)
16 Carlton House Terrace
London SW1Y 5AH

Contact: Dr T Murray
Tel: 020 72104377

The Crown Estate
(Scottish Waters)
10 Charlotte Street
Edinburgh EH2 4DR

Contact: Ian Leaver
Tel: 0131 226 7241
Fax: 0131 220 1366

Maritime and Coastguard Agency Sunley House
90 High Holborn
London WC1V 6LP
Maritime and Coastguard Agency MRCC Aberdeen
Search and Rescue Region Aberdeen
Blaikies Quay
Aberdeen AB1 2PB
Maritime and Coastguard Agency MRCC Yarmouth
4th Floor
Havenbridge House
Great Yarmouth
Norfolk NR30 1HZ
Maritime and Coastguard Agency

(Northern Ireland)

Marine Office
The Design Centre
39 Corporation Street
Belfast BT1 3BA
Non -government organisations  
British Telecom BT Worldwide Networks
Global Networks
18-20 Millbrook Road East
Hampshire SO15 1HY

Contact: Stephen Jackman
Tel: 02380 837930

Joint Nature Conservation Committee Dunnet House
7 Thistle Place
Aberdeen AB10 1UZ

Contact: David Simmons
Tel: 01224 655716
Fax: 01224 621488

The Isle of Wight County Council County Hall
Isle of Wight PO30 1UD
Fishing organisations  
National Federation of Fishermen's Organisations Marsden Road
Fish Docks
South Humberside DN31 3SG

Tel: 01472 352141

Scottish Fishermen's Federation 14 Regent Quay
Aberdeen AB11 5AE

Contact: Michael Sutherland
Tel: 01224 582583
Fax: 01224 574958

Fishermen's Association Limited c/o Roddy McColl
11 Burns Road
Aberdeen AB15 4NT

Tel: 01224 313473
Fax: 01224 310385

Northern Ireland Fish Producers' Organisation Limited Coastguard Cottages
The Harbour
Co. Down BT22 1EA
The Anglo-North Irish Fish Producers' Organisation Limited The Harbour
Co Down

Back | Title | Table of Contents
Appendix 1 | Appendix 2 | Appendix 3 | Appendix 4 | Appendix 5 | Appendix 6 | Appendix 7 | Appendix 8 | Appendix 9
Appendix 10 | Appendix 11 | Appendix 12 | Appendix 13 | Appendix 14 | Appendix 15 | Appendix 16 | Appendix 17
Index Map | Plate 1 | Plate 2W | Plate 2E | Plate 3W | Plate 3E | Plate 4W | Plate 4E | Plate 5 | Plate 6
Plate 7 | Plate 8W | Plate 8E | Plate 9W | Plate 9E | Plate 10W | Plate 10E | Plate 11 | Plate 12 | Legend