SIST-TS CEN/TS 12007-6:2021

SLOVENSKI STANDARD
SIST-TS CEN/TS 12007-6:2021
01-maj-2021
Infrastruktura za plin - Cevovodni sistemi za najvišji delovni tlak do vključno 16
bar - 6. del: Posebne funkcionalne zahteve za neplastificirani (nemehčani)
poliamid (PA-U)
Gas infrastructure - Pipelines for maximum operating pressure up to and including 16 bar
- Part 6: Specific functional recommendations for unplasticized polyamide (PA-U)
Gasinfrastruktur - Rohrleitungen mit einem maximal zulässigen Betriebsdruck bis
einschließlich 16 bar - Teil 6: Spezifische funktionale Anforderungen für
weichmacherfreies Polyamid
Infrastructures gazières - Canalisations pour pression maximale de service inférieure ou
égale à 16 bar - Partie 6 : Recommandations fonctionnelles spécifiques pour le
polyamide non plastifié (PA-U)
Ta slovenski standard je istoveten z: CEN/TS 12007-6:2021
ICS:
83.140.40 Gumene cevi Hoses
91.140.40 Sistemi za oskrbo s plinom Gas supply systems
SIST-TS CEN/TS 12007-6:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS CEN/TS 12007-6:2021

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SIST-TS CEN/TS 12007-6:2021


CEN/TS 12007-6
TECHNICAL SPECIFICATION

SPÉCIFICATION TECHNIQUE

March 2021
TECHNISCHE SPEZIFIKATION
ICS 23.040.20
English Version

Gas infrastructure - Pipelines for maximum operating
pressure up to and including 16 bar - Part 6: Specific
functional recommendations for unplasticized polyamide
(PA-U)
Infrastructures gazières - Canalisations pour pression Gasinfrastruktur - Rohrleitungen mit einem maximal
maximale de service inférieure ou égale à 16 bar - zulässigen Betriebsdruck bis einschließlich 16 bar -
Partie 6 : Recommandations fonctionnelles spécifiques Teil 6: Spezifische funktionale Anforderungen für
pour le polyamide non plastifié (PA-U) weichmacherfreies Polyamid
This Technical Specification (CEN/TS) was approved by CEN on 25 January 2021 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to
submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS
available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in
parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 12007-6:2021 E
worldwide for CEN national Members.

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Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 5
4 Symbols and abbreviations . 6
5 Design . 7
5.1 General . 7
5.2 Materials and components . 7
5.3 Maximum operating pressure . 7
5.3.1 General . 7
5.3.2 Verification of the overall service (design) coefficient . 7
5.3.3 Verification of the RCP criterion . 7
5.4 Assembly techniques . 9
5.5 Material properties for flow stopping by squeeze-off . 9
6 Construction . 9
6.1 Storage, handling and transportation . 9
6.2 Jointing . 10
6.2.1 General . 10
6.2.2 Fusion jointing . 10
6.2.3 Mechanical joints. 11
6.3 Laying . 11
6.4 Connection to existing systems . 13
6.4.1 Static electricity . 13
6.4.2 Squeeze-off . 13
7 Quality control . 13
7.1 Inspection prior to installation . 13
7.2 Inspection during laying . 13
7.2.1 Laying . 13
7.2.2 Joint integrity . 13
8 Pressure testing . 14
9 Influence of media on PA-U . 14
Annex A (informative) Storage, handling and transportation . 15
Annex B (informative) Fusion joint integrity . 19
Bibliography . 26

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European foreword
This document (CEN/TS 12007-6:2021) has been prepared by Technical Committee CEN/TC 234 “Gas
infrastructure”, the secretariat of which is held by DIN.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
The basis if this document has been provided by an Ad Hoc group of interested parties consisting
variously of pipe manufacturers, material suppliers and gas network engineers. The aim is to support
the introduction of Polyamide pipe, PA-U, into Europe for use in natural gas pipe networks operating at
working pressures up to and including 16 bar. The Secretariat of the Ad Hoc group was held by NEN.
This document is part of the following series of standards, of which the parts 1 to 4 and this document
are in the responsibility of CEN/TC 234 Working Group 2, Secretariat held by BSI and of which part 5 is
in the responsibility of CEN/TC 234 Working Group 10, Secretariat held by NSAI:
— Part 1: General functional requirements
— Part 2: Specific functional requirements for polyethylene (MOP up to and including 10 bar)
— Part 3: Specific functional requirements for steel
— Part 4: Specific functional requirements for renovation
This document has been written in the style and form of the above functional EN standards, but at this
time has the status only of a CEN TS. This document will be amended under the authority of CEN/TC
234 as soon as more supporting evidence of the safe use of PA-U becomes available.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
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1 Scope
This document describes the specific functional requirements for polyamide (PA) pipelines in addition
to the general functional requirements of EN 12007-1 for:
a) a maximum operating pressure (MOP) up to and including 16 bar;
b) an operating temperature between −20 °C and +40 °C.
This document covers one type of pipe:
— PA pipes single layer solid wall.
This document specifies common basic principles for gas infrastructure.
NOTE 1 Users of this document are aware that more detailed national standards and/or code of practice can
exist in the CEN member countries.
This document is intended to be applied in association with these national standards and/or codes of
practice setting out the above-mentioned basic principles.
NOTE 2 In the event of conflicts in terms of more restrictive requirements in national legislation/regulation
with the requirements of this document, the national legislation/regulation takes precedence as illustrated in
CEN/TR 13737 (all parts).
CEN/TR 13737 (all parts) give:
— clarification of all legislations/regulations applicable in a member state;
— if appropriate, more restrictive national requirements;
— a national contact point for the latest information.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN ISO 16486-1:2020, Plastics piping systems for the supply of gaseous fuels — Unplasticized polyamide
(PA-U) piping systems with fusion jointing and mechanical jointing — Part 1: General (ISO 16486-1)
EN ISO 16486-2:2020, Plastics piping systems for the supply of gaseous fuels — Unplasticized polyamide
(PA-U) piping systems with fusion jointing and mechanical jointing — Part 2: Pipes (ISO 16486-2)
EN ISO 16486-3, Plastics piping systems for the supply of gaseous fuels — Unplasticized polyamide (PA-U)
piping systems with fusion jointing and mechanical jointing — Part 3: Fittings (ISO 16486-3)
EN ISO 16486-4, Plastics piping systems for the supply of gaseous fuels — Unplasticized polyamide (PA-U)
1
piping systems with fusion jointing and mechanical jointing — Part 4: Valves
EN ISO 16486-5, Plastics piping systems for the supply of gaseous fuels — Unplasticized polyamide (PA-U)
piping systems with fusion jointing and mechanical jointing — Part 5: Fitness for purpose of the system
2
(ISO/DIS 16486-5)

1
Under preparation. Stage at the time of publication: prEN ISO 16486-4.
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EN 12327, Gas infrastructure — Pressure testing, commissioning and decommissioning procedures -
Functional requirements
ISO 12176-1, Plastics pipes and fittings — Equipment for fusion jointing polyethylene systems — Part 1:
3
Butt fusion
ISO 12176-2, Plastics pipes and fittings — Equipment for fusion jointing polyethylene systems — Part 2:
4
Electrofusion
ISO 17885, Plastic piping systems — Mechanical fittings for pressure piping systems — Specifications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
3.1
nominal outside diameter
d
n
specified outside diameter
3.2
nominal wall thickness
e
n
numerical designation of the wall thickness of a component, which is a convenient round number,
approximately equal to the manufacturing dimension in millimetres
3.3
standard dimension ratio
SDR
number approximately equal to the quotient of the nominal outside diameter and the nominal wall
thickness
3.4
maximum operating pressure
MOP
maximum pressure at which a system can be operated continuously under normal operating conditions
Note 1 to entry: Normal operating conditions are: no fault in any device or stream.

2
Under preparation. Stage at the time of publication: prEN ISO 16486-5.
3
This standard is also applicable for PA-U without any changes.
4
This standard is also applicable for PA-U without any changes
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3.5
maximum incidental pressure
MIP
maximum pressure which a system can experience during a short time limited by the safety devices
3.6
butt fusion joint
method of jointing PA-U pipes and fittings where the two pipe ends are heated and brought together to
be fused without the use of a separate fitting or filler material
3.7
electrofusion joint
method of jointing PA-U pipes, using fittings which have an integrated electric heating element
3.8
squeeze-off
act of squeezing a pipe to prevent the flow of gas
3.9
minimum required strength
MRS
value of the lower confidence limit rounded down to the next lower value of the R10 series when the
lower confidence limit is below 10 MPa, or to the next lower value of the R20 series when the lower
confidence limit is 10 MPa or greater
Note 1 to entry: R10 and R20 series are the Renard number series conforming to ISO 3 and ISO 497.
3.10
lower confidence limit
LCL
quantity, expressed in MPa, which can be considered as a material property, representing the 97,5 %
lower confidence limit of the predicted long term hydrostatic strength for water at 20 °C for 50 years
3.11
critical rapid crack propagation pressure
P
RCP
pressure level at which a rapid crack propagation (RCP) can occur in a PA-U pipeline, defined at a
reference temperature
Note 1 to entry: Reference temperature is 0 °C.
4 Symbols and abbreviations
PA-U unplasticized polyamide
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5 Design
5.1 General
The PA-U products are covered by CEN/TC 155, Plastics piping systems and ducting systems. Purchasing
products to CEN standards can be part of a quality programme to ensure the safety and integrity of gas
systems over their design life in service.
The selection of materials, SDR series, dimensions and assembling techniques shall be the responsibility
of the pipeline operator.
5.2 Materials and components
PA-U materials and components used shall comply with EN ISO 16486-1, EN ISO 16486-2,
1 2
EN ISO 16486-3, EN ISO 16486-4 and EN ISO 16486-5 .
Other components not covered by future EN ISO 16486-1, EN ISO 16486-2, EN ISO 16486-3,
1 2
EN ISO 16486-4 and EN ISO 16486-5 shall conform to the relevant European Standards and
International Standards or, in their absence, to national or other established standards and shall be fit
for their purpose.
5.3 Maximum operating pressure
5.3.1 General
The MOP should be selected on the basis of the gas infrastructure operating requirements provided that
the MOP does not exceed 16 bar and the conditions in 5.3.2 and 5.3.3 are satisfied.
5.3.2 Verification of the overall service (design) coefficient
The overall service (design) coefficient C shall be calculated using the formula as given below and in
Figure 1 shall be greater than or equal to 2. This coefficient C takes into consideration service conditions
as well as the properties and components of a pipeline.
20× MRS
C≥
(1)
MOP× SDR−×1 D
( )
F
All pressures measured in bar.
Derating factor (D ) is a coefficient used in the calculation of MOP which takes into account the
F
influence of operating temperature.
NOTE Derating factors are listed in Annex A of ISO 16486-6:2012 will be moved to Annex A of
2
EN ISO 16486-5 during the ongoing revision.
5.3.3 Verification of the RCP criterion
The ratio of critical RCP pressure to MOP shall be greater than or equal to 1,5 (according to
EN ISO 16486-2)
The RCP criterion is the critical pressure, is dependent on pipe size and material, and shall be
determined in accordance with EN ISO 16486-2.
The critical RCP pressure is based on a temperature of 0 °C.

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Where pipe temperature decreases below 0 °C the P /MOP ratio should be recalculated in
RCP
2
accordance with EN ISO 16486-5 using a value of RCP pressure determined from the minimum
expected operating temperature of the pipe. The value of MOP should be reduced so as to maintain the
P /MOP ratio at a value greater than or equal to 1,5. See Figure 1.
RCP

Key
P pressure levels
P critical rapid crack propagation pressure
RCP
STP maximum strength test pressure
max
STP minimum strength test pressure
min
MIP maximum incidental pressure
MOP maximum operating pressure
Figure 1 — Pressure conditions in a PA-U-system
System design:
20× MRS
MOP≤

C× SDR−×1 D
( )
F
P
RCP
MOP≤
(2)
1,5
Pressure testing:
20MRS
1,5× MOP≤ STP≤ (3)
SDR− 1
MIP< STP≤ 09, P
(4)
RCP
2
NOTE For RCP conditions see EN ISO 16486-2 and EN ISO 16486-5 .
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5.4 Assembly techniques
Jointing procedures can vary depending upon the PA-U material and sizes used.
The acceptable jointing methods that shall be used are:
— fusion joints; or
— mechanical joints.
Joints made between new and existing PA-U gas pipework shall be compatible with the materials being
joined.
Components made from PA-U 11 shall be heat fusion jointed only to components made from PA-U 11.
Components made from PA-U 12 shall be heat fusion jointed only to components made from PA-U 12.
Components made from PA-U are not fusion compatible with components made from other polymers.
2
NOTE Test methods for assuring fusibility are given in EN ISO 16486-3 and EN ISO 16486-5 .
The fusion jointing techniques for the construction of PA-U pipelines shall be butt fusion and
electrofusion.
Written jointing procedures, authorized by the pipeline operator, shall be available prior to the
construction of a pipeline.
5.5 Material properties for flow stopping by squeeze-off
When squeeze-off techniques are considered, the suitability of pipe for squeeze-off shall be established
in accordance with EN ISO 16486-2:2020, Annex A, as the described methodology is applicable for PA-
U.
NOTE In publication [8] the squeeze-off behaviour of PA-U 12 pipes is shown.
6 Construction
6.1 Storage, handling and transportation
Care shall be taken during the transport, handling and storage of pipes, fittings and other components
to ensure at all stages that their specified properties and conditions, which can be affected by
environmental factors, are preserved and that physical damage and distortions are avoided.
Pipes and fittings shall be inspected and those pipes with surface defects deeper than 10 % of the
nominal wall thickness shall not be used. For pipe areas which are foreseen for jointing the surface shall
be free of damages which would potentially effect the life time of the system.
PA-U pipes and fittings stored outside are subjected to UV degradation when exposed to direct daylight.
2
PA-U materials are stabilized to give protection for a UV radiation level of 3,5 GJ/m . National bodies
should give recommendations for allowed storage times in their countries. The average radiation level
for one year in European countries are given in Figure 2.
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Figure 2 — Isobaric curves of global radiation in gigajoules per square metre per year in Europe
Pipes shall not be used where it is considered that they have exceeded the maximum UV exposure limit,
unless they have been tested to demonstrate acceptable performance in accordance with existing
standards.
Further guidance on storage, handling and transportation of PA-U pipes and fittings is given in Annex A.
6.2 Jointing
6.2.1 General
Proven competence in PE jointing methods in accordance with national or local standards is the
minimum requirement in combination with a PA specific instruction, considering also the higher safety
demands of high pressure gas piping systems.
NOTE The inclusion of PA-U is also foreseen in EN 13067:2020.
Jointing procedures shall be carefully followed to obtain good quality joints. Cleanliness and the
absence of stress are essential for reliable joints.
6.2.2 Fusion jointing
Fusion equipment shall conform to ISO 12176-1 for butt fusion. Procedures on butt fusion jointing are
given in ISO 21307, the fusion jointing parameters for PA-U can be taken from ISO 16486 series.
NOTE 1 For dual low pressure fusion jointing procedure no parameters have been verified.
Fusion equipment shall conform to ISO 12176-2 for electrofusion. Refer to the manufacturer’s
instructions for electrofusion jointing.
NOTE 2 ISO 12176-1 and ISO 12176-2. These standards are applicable to PA-U as well. The same machines can
be used with different settings.
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Consideration shall be given to the use of shielding, end caps or longer heating times when jointing in
adverse weather conditions.
NOTE 3 Harsh environmental conditions (like strong wind, cold temperatures, rain, extreme humidity, high
dust loads, etc.) or contamination can reduce the quality of the PA fusion joint, when not protected.
Pipes and/or fittings with fusion ends of different SDR values shall not be jointed by butt fusion.
The following are minimum requirements for the assembly of fusion joints:
— cleaning of the pipe and/or fitting ends and the surface of the heated tools;
— protection against dust and other contaminating influences;
— clamping of the pipe and/or fitting ends;
— verification of the alignment and the gap between fitting and/or pipe ends;
— use of re-rounding clamps where pipe ovality exists;
— preparation of the fusion surfaces;
— marking for depth of penetration into the electrofusion sockets;
— maintenance and correct functioning of the fusion equipment and check of its compatibility with
the required parameters;
— taking into account the fusion parameters as written in the jointing procedure.
6.2.3 Mechanical joints
6.2.3.1 General
All mechanical fittings including transition fittings shall comply with the ISO 16486 series and
ISO 17885.
All mechanical joints shall be assembled in accordance with the manufacturer’s instructions and the
metallic parts of fittings shall be corrosion resistant or protected against corrosion.
Satisfactory mechanical jointing procedures based upon recognized standards, manufacturers'
instructions and the experience of the pipeline operator shall be utilized.
6.2.3.2 Flanged joints
Flanged joints shall be made using the appropriate jointing material.
6.2.3.3 Threaded joints
PA-U pipes shall not be threaded.
6.3 Laying
Care shall be taken to prevent damage to the pipes and fittings during the whole process of laying.
Changes of direction of a PA-U pipeline during construction shall be achieved by means of preformed
bends or elbow fittings or by the natural flexibility of the PA-U pipe within limits. Natural flexing may be
used for bend radii greater than or equal to 25 × d mm, and for smaller radii dependent upon the SDR
n
and material properties based on operational experience and good engineering practice.
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For pipes made of any thermoplastic materials for the minimum bending radii also ambient
temperature influences have to be considered.
Machine bending of pipes or bending following the application of heat shall not be used.
PA-U pipes, fittings and valves installed above ground shall be protected against mechanical
interference and UV degradation.
When using carrier pipes the gas pipe should be adequately supported. To prevent damage, contact
with sharp edges should be avoided.
When tightening or untightening a mechanical joint movement, shall not be transmitted to the pipe.
EXAMPLE Torsion.
Consideration shall be given during the laying process to the potential effects on the pipe of relative
movements of the ground or adjacent constructions or from temperature variations.
Where the PA-U pipe is laid by drag, care shall be taken that the drag force is not greater than the values
(in newtons) given by the formula:
2
σ×Π × d
e
F=
(5)
SF× SDR
σ
yield
σ=
(6)
1,25
where
F is the maximum drag force, in newtons;
σ is the limiting stress in the PA-U in MPA;
σ is the tensile stress at yield in MPA;
yield
d is the outside nominal diameter of the pipe;
n
SF is the safety factor;
SDR is the standard dimension ratio;
d is the external diameter of the pipe, in millimetres.
e
Pipes shall not be overstressed by tensile forces during laying: The limiting stress shall be 1,25 times
lower than the yield stress for the relevant temperature, as provided by the resin producer.
A safety factor between 2 and 3 is recommended, depending on site and installation conditions.
Other values of limiting stress σ and safety factor SF may be used for given grades of PA-U on the
engineer’s responsibility to ensure safety.
Stresses caused by different temperatures between laying and operation shall be considered.
Valves shall be installed so that they do not expose the PA-U pipe to unnecessary stress during opening
and closing cycles.
Material around the pipe shall be compacted so as to avoid excessive pipe ovality and shall be done
layer by layer.
Backfill materials around the pipe shall be selected to prevent damage to the pipe from contact with
sharp edges during and after compaction.
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6.4 Connection to existing systems
6.4.1 Static electricity
Where there can be a release of gas in the working area, static charge accumulation shall be avoided.
EXAMPLE Draping water
...