EN 13480-6:2024

SLOVENSKI STANDARD
01-december-2024
Nadomešča:
SIST EN 13480-6:2018
SIST EN 13480-6:2018/A1:2019
Kovinski industrijski cevovodi - 6. del: Dodatne zahteve za vkopane cevovode
Metallic industrial piping - Part 6: Additional requirements for buried piping
Metallische industrielle Rohrleitungen - Teil 6: Zusätzliche Anforderungen an
erdgedeckte Rohrleitungen
Tuyauteries industrielles métalliques - Partie 6: Exigences complémentaires pour les
tuyauteries enterrées
Ta slovenski standard je istoveten z: EN 13480-6:2024
ICS:
23.040.10 Železne in jeklene cevi Iron and steel pipes
77.140.75 Jeklene cevi in cevni profili Steel pipes and tubes for
za posebne namene specific use
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 13480-6
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2024
EUROPÄISCHE NORM
ICS 23.040.01 Supersedes EN 13480-6:2017
English Version
Metallic industrial piping - Part 6: Additional requirements
for buried piping
Tuyauteries industrielles métalliques - Partie 6: Metallische industrielle Rohrleitungen - Teil 6:
Exigences complémentaires pour les tuyauteries Zusätzliche Anforderungen an erdgedeckte
enterrées Rohrleitungen
This European Standard was approved by CEN on 9 July 2024.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

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, Türkiye 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
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13480-6:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 General . 5
4.1 Safety . 5
4.2 Routes . 6
4.3 Depth of installation. 6
4.4 Pipes marking and recording . 6
4.5 Internal inspection provisions . 6
4.6 Contents removal . 6
4.7 Trench drainage . 6
5 Materials . 7
6 Design and calculation . 7
6.1 Minimum wall thickness for buried piping . 7
6.2 Design . 7
7 Installation . 8
7.1 Trenches . 8
7.2 Pipe laying . 9
7.3 Back filling . 9
8 Sleeves or casings . 9
9 Corrosion protection. 9
9.1 General . 9
9.2 Coatings . 10
9.3 Cathodic protection . 10
10 Examination and testing . 10
Annex A (normative) Calculations for buried piping . 11
A.1 General . 11
A.2 Materials . 11
A.3 Design and calculation . 11
A.3.1 Calculation procedure . 11
A.3.2 Determination of the loads due to backfill . 11
A.3.3 Determination of the loads due to live loads . 23
A.3.4 Determination of the moments acting upon the piping . 27
A.3.5 Global stability of a buried piping system . 29
Annex Y (informative) History of EN 13480-6 . 34
Y.1 Differences between EN 13480-6:2017 and EN 13480-6:2024 . 34
Annex ZA (informative)  Relationship between this European Standard and the Essential
Requirements of EU Directive 2014/68/EU aimed to be covered. 35
Bibliography . 36

European foreword
This document (EN 13480-6:2024) has been prepared by Technical Committee CEN/TC 267 “Industrial piping
and pipelines”, the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by December 2024, and conflicting national standards shall be withdrawn
at the latest by December 2024.
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.
This document supersedes EN 13480-6:2017.
This new edition incorporates the Amendments which have been approved previously by CEN members, and
the corrected pages up to Issue 2 without any further technical change. Annex Y provides details of significant
technical changes between this European Standard and the previous edition.
This document has been prepared under a standardization request addressed to CEN by the European
Commission. The Standing Committee of the EFTA States subsequently approves these requests for its
Member States.
For the relationship with EU Legislation, see informative Annex ZA, which is an integral part of this document.
This European Standard EN 13480 for metallic industrial piping consists of eight interdependent and not
dissociable Parts which are:
 Part 1: General;
 Part 2: Materials;
 Part 3: Design and calculation;
 Part 4: Fabrication and installation;
 Part 5: Inspection and testing;
 Part 6: Additional requirements for buried piping;
 CEN/TR 13480-7, Guidance on the use of conformity assessment procedures;
 Part 8: Additional requirements for aluminium and aluminium alloy piping.
Although these Parts may be obtained separately, it should be recognized that the Parts are inter-dependant.
As such the manufacture of metallic industrial piping requires the application of all the relevant Parts in order
for the requirements of the Standard to be satisfactorily fulfilled.
This European Standard will be maintained by a Maintenance MHD working group whose scope of working is
limited to corrections and interpretations related to EN 13480. The contact to submit queries can be found at
https://unm.fr/en/maintenance-agencies/maintenance-agency-en-13480/.
A form for submitting questions can be downloaded from the link to the MHD website. After subject experts
have agreed an answer, the answer will be communicated to the questioner. Interpretation sheets will be
posted on the website of the MHD.
Amendments to this new edition may be issued from time to time and then used immediately as alternatives
to rules contained herein. These amendments will be consolidated within EN 13480:2024 in accordance with
the maintenance system of EN 13480 series approved by CEN/BT Decision C172/2021.
Any feedback and questions on this document should be directed to the users’ national standards body. A
complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: 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, Türkiye and the United Kingdom.

1 Scope
This document specifies requirements for industrial piping either totally buried or partly buried and partly
run in sleeves or similar protection. It is used in conjunction with the other six parts of
EN 13480:2024 series.
Where buried piping subject to this standard connects to piping installed under other jurisdiction such as
pipelines, the transition can be made at a closing element e.g. an isolating or regulating valve separating the
two sections. This can be close to the boundary of the industrial site, but can be inside or outside the boundary.
Operating temperature up to 75 °C.
NOTE For higher temperatures reference can be made to EN 13941-1:2019+A1:2021 and
EN 13941-1:2019+A1:2021, but it is kept in mind, that CEN/TC 107 only deals with pre-insulated piping with
temperatures up to 140 °C and diameters up to 800 mm, which is state of the art for these products.
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 13480-1:2024, Metallic industrial piping — Part 1: General
EN 13480-2:2024, Metallic industrial piping — Part 2: Materials
EN 13480-3:2024, Metallic industrial piping — Part 3: Design and calculation
EN 13480-5:2024, Metallic industrial piping — Part 5: Inspection and testing
3 Terms and definitions
No terms and definitions are listed in this document.
4 General
4.1 Safety
a) Buried piping within an industrial site presents a potential hazard to site personal, equipment and
environment. The sections set out in this document provide guidance as to how the hazard presented by
the piping can be assessed, and the integrity of the piping system maintained.
NOTE 1 Attention is drawn to appropriate National or Local regulations.
b) The main factors to be considered are:
 Design including Routing, Layout, Interaction with connecting systems;
 Materials and Construction Specification and Quality Control;
 Operating Procedures and Control;
 Corrosion protection;
 External Impact Protection and Mitigation.
All of these factors interact.
NOTE 2 It is recommended that all buried piping be subjected to a formal hazard analysis procedure.
NOTE 3 Attention is drawn to appropriate National or Local regulations.
c) Additional safety requirements can be specified for group 1 fluids according to EN 13480-1:2024,
including automated means of isolating buried sections of piping.
4.2 Routes
All routes for buried piping shall be agreed with the owner and operator of the site. The site owner shall be
required to furnish details of all other actual or planned buried services (including cables) and all roadways
or other surface loads within the construction working width or zone of the proposed pipe.
Piping in category III according to EN 13480-1:2024 shall be separated from any other pipe or service by a
minimum distance of 0,25 m unless it can be demonstrated that a smaller distance is acceptable.
4.3 Depth of installation
In the absence of special protection (e.g. concrete slabs) buried piping shall be provided with a minimum cover
of 0,8 m.
The designer shall consider increasing the extent of cover above the minimum where penetrating cold or frost
heave of the ground is likely, or where damage from excavation activities is a possibility.
4.4 Pipes marking and recording
Buried pipes shall be marked by a continuous tape or other agreed means placed directly above the pipe and
no closer than 0,3 m.
All buried pipes shall be identified on as-installed drawings which accurately locate the route relative to
structures or other permanent features. The site owner can require the route to be physically marked by the
use of identification posts or cover slabs at appropriate intervals.
4.5 Internal inspection provisions
Where periodic internal inspection of buried piping is anticipated, and the specification identifies the method
proposed, the designer shall incorporate appropriate means of introducing and removing the inspection
devices. Such closures, and openings for inspection shall be designed in accordance with
EN 13480-3:2024.
4.6 Contents removal
The design of the piping system shall make allowance for the safe filling and removal of the contents. This shall
include vent and drain points or falls as required, and the selection of appropriate bends and fittings.
4.7 Trench drainage
The designer shall recognize that pipe trenches for buried piping can act as channels for ground water.
Appropriate means shall be employed to ensure that the bottom of the trench has sufficient slope to soak-
aways or sumps to prevent accumulation of water around the piping. Where such measures are not possible,
the designer shall include the possibility of flotation in the design calculations.
In addition, the drainage arrangements shall dispose of the hydrostatic test water. Care shall be exercised
during this operation to ensure that washout of bedding material does not occur.
5 Materials
Materials shall conform to the requirements of EN 13480-2:2024 except that the value for the specified
minimum elongation after fracture for the longitudinal direction (see EN 13480-2:2024, 4.1.4.) shall be 20 %.
Materials with elongation values less than 20 % shall be avoided, and shall only be used subject to agreement
between the purchaser and the designer.
6 Design and calculation
6.1 Minimum wall thickness for buried piping
Unless the pressure design calculations lead to a greater thickness, the wall thickness of the pipe shall not be
lower than the value given in Table 1.
Table 1 — Minimum wall thickness for buried piping
Nominal size (DN) Minimum thickness
mm
3,2
DN ≤ 80
4,7
80 < DN ≤ 150
6,35
150 < DN ≤ 450
7,9
450 < DN ≤ 600
9,5
600 < DN ≤ 950
950 < DN 1 % DN
6.2 Design
6.2.1 A simple single dimensional model linking buried pipes and the surrounding ground can be sufficient
for piping designed in accordance with EN 13480-3:2024. More complex analysis of pipe to soil interaction
can be used where sufficient accurate geo-mechanical data is available, or where the conditions of this annex
cannot be met.
NOTE It is assumed that the loads imposed by the piping on the soil do not exceed its load bearing capacity.
6.2.2 The designer shall include in the calculations the weight of soil or backfill above the pipe and the
maximum predicted value of traffic or other static and dynamic loads imposed on the ground above the pipe.
With a minimum immediate (first) cover to the pipe of 150 mm of sand, or similar free-flowing material, the
forces can be considered as acting over the entire 180° of the upper pipe surface.
6.2.3 In addition to calculations at the design pressure, the loadings on the unpressurized system shall be
calculated.
6.2.4 Pipe movement will be significantly restrained by the frictional force at the interface with the
surrounding soil, and can be effectively prevented at buried bends and large branches. Unless specific
measures are incorporated to permit relative movement, buried pipes shall be considered as fully restrained
axially for calculation purposes.
The axial stress due to combined pressure and temperature change effects shall be calculated as follows:
S ν SE− α∆()T (1)
Lp
where
S is the axial stress ≤ 0,90 × yield strength at design temperature;
L
S is the circumferential stress due to pressure alone;
p
ΔT is the maximum temperature range;
ν
is Poisson’s ratio;
α is the thermal expansion factor;
E is the Young modulus.
6.2.5 Where no detailed analysis is undertaken, the maximum temperature range (including the installation
temperature) shall not exceed 35 °C, and restraining features such as buried bends and tees shall have a
separation of not less than 5 DN. Where detailed analysis is undertaken, it shall be in accordance with
EN 13480-3:2024 supplemented by Annex A (normative).
6.2.6 Where seismic events are to be considered, the pipe shall be treated as if rigidly connected to the
ground and following the imposed displacements. Dynamic amplification can be ignored.
NOTE The surrounding soil can be considered to effectively dampen all harmonic excitations of the pipe.
6.2.7 The designer shall consider the interface between buried and above ground sections of the piping for
all design conditions.
For the static analysis, the buried part shall be considered as clamped for thermal expansion, and it shall be
ensured that the flexibility of the above ground part is sufficient in order to limit the loads at the connection
of the two parts to acceptable values.
The designer shall analyse the effects of any anticipated settlement of the buried piping relative to the
connected piping overground or in ducts, and shall ensure compliance with the requirements of this
document.
NOTE When gaseous fluids are carried by the piping, the designer can note the likely rise in temperature in the
discharge lines of a compressor and corresponding reduction at the outflow from pressure reducing equipment.
Where such in-line items are close to a buried section, the designer shall consider the effects of the
temperature change.
7 Installation
7.1 Trenches
7.1.1 The normal method of installation shall be by the excavation of trenches. Alternatively, sections of
underground pipe installed by thrust boring or similar trenchless methods shall be set in casings.
7.1.2 The bottom of the trench shall be consolidated and free from sharp objects, rocks or stones. The trench
shall be made with sufficient slope to provide drainage for the pipe to minimise flotation and corrosion. Where
necessary, soak-aways or sumps shall be provided.
The piping shall be laid on an even bed of sand or similar material and consequently the longitudinal bending
stress due to weight can be discounted.
=
7.1.3 A bedding base of free-flowing material such as rounded sand or fine gravel shall be provided with
sufficient depth to support the pipe and assist drainage.
7.2 Pipe laying
7.2.1 The trench shall be substantially free of water before the pipe is placed in position.
7.2.2 Provision shall be made for sufficient access to joints to permit proper examination during hydrostatic
or other testing operations, and to wrap or otherwise protect pipe joints in the trench. Adequate means shall
be provided for removing the hydrostatic test water from the pipe and trench.
7.2.3 The bore of the piping shall be clean to the required standard before laying in the trench.
7.2.4 All practical means shall be taken to prevent damage to the pipe and its coatings in storage and during
pipe laying. Wire ropes and chains shall not be used for lifting. Protective pipe coatings shall be visual
examined or high voltage tested after the pipe is laid and prior to back filling the excavation.
7.3 Back filling
7.3.1 All tie and examination operations shall be completed before backfilling.
7.3.2 The first cover of the piping shall be made using free-flowing materials to a minimum depth of 150 mm,
ensuring that the whole circumference of the pipe is in contact with the filling.
7.3.3 The remaining backfilling shall be the same material that was excavated to form the trench or of similar
characteristics. No vegetable or waste matter shall be incorporated. Compacting shall not commence before a
cover of 0,3 m has been achieved.
8 Sleeves or casings
Where buried piping is subjected to frequent overhead traffic or occasional heavy loads, consideration shall
be given to providing the pipe with an external protective sleeve or casing. These shall also be employed for
sections installed by thrust boring or similar means.
Casings shall be of steel, concrete or plastic composition with a diameter providing a minimum of
100 mm clearance from the carrier pipe.
They shall be constructed to carry all likely external loads, without consideration of the carrier pipe and any
internal supports. The thicknesses of steel tubing shall not be less than the values required by
EN 13480-3:2024 according to the loads applied (with a minimum of 9,5 mm).
Not less than 3 supporting centralising spacers shall be installed around the pipe at intervals not exceeding
the span requirements with a maximum of 4 m.
Casings shall be sealed at their ends to prevent the ingress of water or other foreign matter. If the annulus
between carrier and sleeve pipes is to be filled with a fluid, the seal need only be sufficient to withstand the
pressure of the filler unless, otherwise specified by the purchaser.
9 Corrosion protection
9.1 General
Buried piping shall be protected from external corrosion which can arise from water and ground
contaminants, and the effects of stray earth electrical currents. Protection shall be provided by a combination
of coating the pi
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