Technical Rule – Code of Practice
DVGW G 466-1 (A)  November 2012
Steel gas pipelines with an operating pressure greater
than 5 bar – Maintenance
Warning
This English-language version is an informal translation from the German original. However, only the
original German-language version has been exclusively authorised by the DVGW and its Technical Bo dies. The DVGW reserves the right to revise this version at any time due to possible translation errors.
Anybody is free to use the DVGW system of rules. Users are responsible for the proper use of the
DVGW system of rules in each individual case.
The DVGW Deutscher Verein des Gas- und Wasserfaches e.V. – Technisch-wissenschaftlicher Verein –
(German Technical and Scientific Association for Gas and Water, a registered association – TechnicalScientific Association) – has been supporting the gas and water industries since 1859 with a focus on
safety, hygiene and the protection of the environment.
Setting the technical rules, the DVGW encourages ongoing progress in the industry. The DVGW and its
approximately 12,000 members elaborate the overall recognised technical rules applicable to gas and
water engineering; they audit and certify products, persons and companies, initiate and support research
projects and offer training courses covering the entire range of relevant gas and water topics.
The DVGW Technical Rules constitute the basis of the technical self-management and self-responsibility
of the German gas and water industry and guarantee the safe and secure supply of gas and water at the
highest international level.
The DVGW is an independent non-profit organisation free from economic lobbyism and political influence.
ISSN 0176-3490
Pricegroup: 6
 DVGW, Bonn, November 2012
DVGW German Technical and Scientific Association for Gas and Water e. V.;
Technical-Scientific Association
Josef-Wirmer-Straße 1–3
D-53123 Bonn/Germany
Phone: +49 228 9188-5
Fax: +49 228 9188-990
E-Mail: [email protected]
Internet: www.dvgw.de
Reprint and photomechanical reproduction, also of excerpts, is only permi tted with the approval of the DVGW e.V.,
Bonn.
Distibution:
Wirtschafts- und Verlagsgesellschaft Gas und Wasser mbH, Josef-Wirmer-Str. 3, D-53123 Bonn
Phone: +49 228 9191-40 ∙ Telefax: +49 228 9191-499
E-mail: [email protected] ∙ Website: www.wvgw.de
Item No.:
Steel gas pipelines with an operating pressure greater than 5 bar –
Maintenance
Content
Foreword ............................................................................................................................................ 5
1
Scope ..................................................................................................................................... 7
2
Normative references ............................................................................................................ 7
2.1
DVGW Technical Rules ........................................................................................................... 7
2.2
National standards................................................................................................................... 8
2.3
Legislation, directives and ordinances ...................................................................................... 9
2.4
Rules and provisions of the Institution for Statutory Accident Insurance and Preventio n ............ 9
2.5
AfK recommendations.............................................................................................................. 9
2.6
AD (pressure vessel committee) instruction bulletins ................................................................ 9
3
Definitions and terms ............................................................................................................ 9
3.1
Maintenance............................................................................................................................ 9
3.2
Inspection ............................................................................................................................... 9
3.3
Service .................................................................................................................................... 9
3.4
Corrective maintenance ........................................................................................................... 9
3.5
Condition analysis ................................................................................................................... 9
4
Maintenance......................................................................................................................... 10
4.1
General ................................................................................................................................. 10
4.2
Technical expert .................................................................................................................... 10
4.3
Competent personnel ............................................................................................................ 10
4.4
Specialists ............................................................................................................................. 11
5
Inspection and service ........................................................................................................ 11
5.1
General ................................................................................................................................. 11
5.2
Pipeline route surveillance and inspection and tightness control ............................................. 11
5.2.1
Pipeline route surveillance and inspection .............................................................................. 11
5.2.1.1 Surveillance on foot and/or mobile survey .............................................................................. 12
5.2.1.2 Surveillance by air ................................................................................................................. 12
5.2.2
Tightness and condition test intervals ..................................................................................... 12
5.2.2.1 Within built-up areas .............................................................................................................. 12
5.2.2.2 Outside built-up areas............................................................................................................ 13
5.2.2.3 Mining subsidence areas ....................................................................................................... 13
5.2.2.4 Pipelines above ground ......................................................................................................... 13
DVGW G 466-1 Arbeitsblatt
03
5.3
Inspection pigging .................................................................................................................. 13
5.4
Cathodic protection ................................................................................................................ 14
5.5
Construction work near gas pipelines ...................................................................................... 14
5.6
Changed operating conditions................................................................................................. 14
5.7
Changed building situation ...................................................................................................... 14
5.8
Gas pipelines in mining subsidence areas ............................................................................... 15
5.9
Pipeline components .............................................................................................................. 15
5.10
Condition analysis .................................................................................................................. 15
5.11
Documentation of monitoring results ....................................................................................... 15
6
Corrective maintenance ....................................................................................................... 15
6.1
General .................................................................................................................................. 15
6.2
Requirements on pipelines and pipeline components............................................................... 16
6.2.1
Pipelines and pipeline components ......................................................................................... 16
6.2.2
Coatings ................................................................................................................................ 16
6.3
Work on purged gas pipelines ................................................................................................. 16
6.3.1
Preparation of work ................................................................................................................ 16
6.3.2
Gas pipeline isolation ............................................................................................................. 17
6.3.2.1 Pipeline isolation under gas-free or under inert gas conditions ................................................. 17
6.3.2.2 Pipeline isolation under live gas conditions ............................................................................. 17
6.3.3
Installation work ..................................................................................................................... 17
6.3.4
Welding preparation ............................................................................................................... 18
6.3.4.1 Welding operations under live gas conditions .......................................................................... 18
6.3.4.2 Welding operations under gas-free or under inert gas conditions ............................................. 19
6.4
Welding under operating pressure on gas pipelines ................................................................. 19
6.5
Hot tapping of gas pipelines .................................................................................................... 19
6.6
Testing ................................................................................................................................... 19
6.7
Documentation of monitoring results ....................................................................................... 20
7
Gas pipeline commissioning ................................................................................................ 20
8
Gas pipeline decommissioning and abandoning ................................................................. 20
8.1
Gas pipeline decommissioning ................................................................................................ 20
8.2
Gas pipeline abandoning ........................................................................................................ 21
Annex A – Typical form for monitoring and corrective maintenance documentation ..................... 23
Annex B – Typical incident report form for immediate recovery...................................................... 24
Annex C – Typical expert's certificate documenting the effectiveness of cathodic protection
as per clause 5.4 ............................................................................................................................... 25
Bibliography ...................................................................................................................................... 26
04 DVGW G 466-1 Code of Practice
Foreword
This DVGW Code of Practice shall be applied in conjunction with the following DIN standards:

DIN EN 1594 “Gas infrastructure - Pipelines for maximum operating pressure over 16 bar - Functional
requirements”,

DIN EN 12007-1 “Gas infrastructure – Pipelines for maximum operating pressure up to and including
16 bar – Part 1: General functional requirements”,

DIN EN 12007-3 “Gas infrastructure – Pipelines for maximum operating pressure up to and including
16 bar – Part 3: Specific functional recommendations for steel”,

DIN EN 12327 “Gas infrastructure – Pressure testing, commissioning and decommissioning procedures – Functional requirements”, and

DIN EN 12732 “Gas infrastructure – Welding steel pipework – Functional requirements”.
These standards describe the general principles relating to the operation and maintenance of gas pip elines. These general principles constitute the minimum requirements agreed on by European experts
involved in the standardisation process; they shall be complemented by more detailed technical rules
and/or national standards and implemented afterwards, as done by this DVGW Code of Practice
G 466-1, “Steel gas pipelines for operating pressures greater than 5 bar – Maintenance”, which is based
on the German gas industry’s safety philosophy that has proven its worth over long years of experience .
The requirements contained in this DVGW Code of Practice shall be understood as binding requirements
that complement the above-mentioned standards.
This Code of Practice supersedes DVGW Code of Practice G 466-1:2002-04.
Amendments
The following amendments have been made compared to DVGW Code of Practice G 466-1:2002-04:
a)
The content of this DVGW Code of Practice has been adapted to reflect the current maintenance
practice for steel gas pipelines with a maximum operating pressure greater than 5 bar and therefore
describes the state of the art.
b)
Inspection pigging and condition analysis have been explicitly included in this DVGW Code of Practice as new measures designed to safeguard gas pipeline integrity.
DVGW G 466-1 Code of Practice
05
c)
The normative references have been updated.
d)
The definition of “condition analysis” has been updated.
e)
The definition of the term “Technical expert” has been adapted to comply with the latest statutory
provisions.
f)
Sections 5.2 and 5.3 have been editorially revised.
Earlier editions
DVGW G 466/I:1969-12
DVGW G 466/I:1976-09
DVGW G 466/I:1984-05
DVGW G 466/I:1989-07
DVGW G 466-1:2002-04
06 DVGW G 466-1 Code of Practice