EN 12493:2020
(Main)LPG equipment and accessories - Welded steel pressure vessels for LPG road tankers - Design and manufacture
LPG equipment and accessories - Welded steel pressure vessels for LPG road tankers - Design and manufacture
This document specifies minimum requirements for materials, design, construction and workmanship procedures, and tests for welded LPG road tanker pressure vessels and their welded attachments manufactured from carbon, carbon/manganese and micro alloy steels.
There is no upper size limit as this is determined by the gross vehicle weight limitation.
This document does not cover pressure vessels for pressure vessel containers.
NOTE 1 In the context of this document, the term "road tanker" is understood to mean "fixed tanks" and "demountable tanks" as defined in ADR.
NOTE 2 The equipment for the pressure vessels and the inspection and testing after assembly is covered by EN 12252 and EN 14334, respectively.
NOTE 3 The design type of the road tanker is subject to approval by the competent authority, as required by ADR.
NOTE 4 This document is intended for LPG only; however, for other liquefied gases see EN 14025.
Flüssiggas-Geräte und Ausrüstungsteile - Geschweißte Druckbehälter aus Stahl für Straßentankwagen für Flüssiggas (LPG) - Auslegung und Herstellung
Dieses Dokument legt Mindestanforderungen an Werkstoffe, Auslegung, Bau und Ausführungsverfahren sowie Prüfungen für geschweißte Druckbehälter für Straßentankwagen für Flüssiggas (LPG, en: liquefied petroleum gas) und deren angeschweißtes Zubehör fest, die aus Kohlenstoffstahl, Kohlenstoff-Manganstahl und mikrolegiertem Stahl hergestellt werden.
Es besteht keine Obergrenze für die Größe, da diese durch die Begrenzung der Bruttomasse des Fahrzeuges festgelegt wird.
Dieses Dokument gilt nicht für Druckbehälter für Tankcontainer.
ANMERKUNG 1 Im Sinne dieses Dokuments ist der Begriff „Straßentankwagen“ entsprechend der Definition im ADR als „fest verbundene Tanks“ und „Aufsetztanks“ zu verstehen.
ANMERKUNG 2 Die Ausrüstung der Druckbehälter sowie die Inspektion und Prüfung nach dem Zusammenbau ist durch EN 12252 bzw. EN 14334 abgedeckt.
ANMERKUNG 3 Das Baumuster des Straßentankwagens unterliegt entsprechend der Anforderung des ADR einer Zulassung durch die zuständige Behörde.
ANMERKUNG 4 Dieses Dokument gilt nur für LPG, andere verflüssigte Gase werden jedoch von EN 14025 abgedeckt.
Équipements pour GPL et leurs accessoires - Réservoirs sous pression en acier soudés des camions-citernes - Conception et construction
Le présent document spécifie les exigences minimales relatives aux matériaux, à la conception, à la construction et à la qualité d’exécution, ainsi que les essais des réservoirs sous pression soudés de camions-citernes utilisés pour le transport du GPL et de leurs accessoires soudés fabriqués en acier au carbone, en acier au carbone/manganèse et en acier micro-allié.
Il ne définit pas de taille limite supérieure pour le réservoir étant donné que celle-ci sera déterminée par la limite du poids total en charge du véhicule.
Le présent document ne couvre pas les réservoirs sous pression destinés à des conteneurs-citernes.
NOTE 1 Dans le cadre du présent document, le terme « camion-citerne » signifie « réservoirs fixes » et « réservoirs démontables » comme définis dans l'ADR.
NOTE 2 L'équipement des camions-citernes et leurs contrôles et essais après construction sont couverts respectivement par les normes EN 12252 et EN 14334.
NOTE 3 Le mode de conception du camion-citerne est sujet à l'approbation de l'autorité compétente comme prévu dans l'ADR.
NOTE 4 Le présent document est uniquement destinée aux GPL ; toutefois, pour d’autres gaz liquéfiés, voir l’EN 14025.
Oprema in pribor za utekočinjeni naftni plin (UNP) - Varjene tlačne posode cestnih cistern iz jekla za UNP - Konstruiranje in izdelava
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-februar-2021
Nadomešča:
SIST EN 12493:2013+A2:2018
Oprema in pribor za utekočinjeni naftni plin (UNP) - Varjene tlačne posode cestnih
cistern iz jekla za UNP - Konstruiranje in proizvodnja
LPG equipment and accessories - Welded steel pressure vessels for LPG road tankers -
Design and manufacture
Flüssiggas-Geräte und Ausrüstungsteile - Geschweißte Druckbehälter aus Stahl für
Straßentankwagen für Flüssiggas (LPG) - Auslegung und Herstellung
Équipements pour GPL et leurs accessoires - Réservoirs sous pression en acier soudés
des camions-citernes pour GPL - Conception et construction
Ta slovenski standard je istoveten z: EN 12493:2020
ICS:
23.020.35 Plinske jeklenke Gas cylinders
43.080.10 Tovornjaki in priklopniki Trucks and trailers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 12493
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2020
EUROPÄISCHE NORM
ICS 23.020.30; 23.020.35 Supersedes EN 12493:2013+A2:2018
English Version
LPG equipment and accessories - Welded steel pressure
vessels for LPG road tankers - Design and manufacture
Équipements pour GPL et leurs accessoires - Flüssiggas-Geräte und Ausrüstungsteile - Geschweißte
Réservoirs sous pression en acier soudés des camions - Druckbehälter aus Stahl für Straßentankwagen für
Conception et construction Flüssiggas (LPG) - Auslegung und Herstellung
This European Standard was approved by CEN on 16 November 2020.
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, 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
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12493:2020 E
worldwide for CEN national Members.
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 8
4 Materials . 9
4.1 Environmental. 9
4.2 Suitability . 9
4.3 Pressure retaining parts . 9
4.4 Non-pressure retaining parts . 9
4.5 Welding consumables . 9
4.6 Non-metallic materials (gaskets) . 10
4.7 Inspection documents for materials . 10
5 Pressure vessel design . 10
5.1 Design conditions . 10
5.2 Minimum thickness . 10
5.3 Surge plates . 11
5.4 Doubler plates . 12
5.5 Stresses due to motion . 12
5.6 Self-supporting pressure vessels. 12
5.7 Vacuum conditions . 12
5.8 Pressure vessel mountings . 12
5.9 Internal pipework . 13
6 Openings . 13
6.1 General . 13
6.2 Reinforcement of openings. 13
6.3 Threaded connections . 13
6.4 Manhole . 13
7 Non-pressure retaining parts . 14
7.1 Attachment welds . 14
7.2 Position of attachment welds . 14
8 Workmanship and construction . 14
8.1 General . 14
8.2 Environment . 14
8.3 Control of materials. 14
8.4 Acceptable weld details . 15
8.5 Heat treatment and forming . 15
8.6 Welding . 17
8.7 Repairs to pressure envelope and direct attachment welds . 19
9 Construction and workmanship of internal pipework . 19
10 Manufacturing tests and examinations . 19
10.1 General . 19
10.2 Mechanical testing . 20
10.3 Non-destructive testing . 21
10.4 Non-destructive testing for welds . 21
10.5 Qualification of non-destructive testing personnel . 22
10.6 Visual examination of welds . 22
10.7 Acceptance criteria . 23
10.8 Safety precautions at the hydraulic test . 23
11 External corrosion protection and finishing . 23
11.1 External protection . 23
11.2 Finishing operations . 23
12 Marking . 23
13 Records and documentation . 23
13.1 Documentation obtained by the manufacturer . 23
13.2 Records prepared by the manufacturer . 23
13.3 Retention and supply of documents . 24
Annex A (normative) Guidance on selection of materials grades . 25
Annex B (normative) Reference temperatures for design . 26
Annex C (informative) Alternative reference temperatures for design . 27
Annex D (normative) Design . 28
Annex E (informative) Example of joints . 43
Annex F (normative) Allowable tolerances . 47
Annex G (normative) Heat treatment . 52
Annex H (informative) Typical method for measurement of shell peaking . 53
Annex I (informative) Choice of non-destructive test methods for welds . 56
Annex J (normative) Hydraulic pressure test . 57
Bibliography . 58
European foreword
This document (EN 12493:2020) has been prepared by Technical Committee /TC 286 “LPG equipment
and accessories”, the secretariat of which is held by NSAI.
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 June 2021, and conflicting national standards shall be
withdrawn at the latest by June 2021.
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 12493:2013+A2:2018.
The following main changes have been introduced during this revision:
— removal of Annex I, Welding imperfections and test specimens;
— addition of normative reference to EN 12972.
This document has been submitted for reference in:
— the RID and/or;
— the technical annexes of the ADR.
NOTE These regulations take precedence over any clause of this document. It is emphasized that
RID/ADR are being revised regularly at intervals of two years which may lead to temporary non-
compliances with the clauses of this document.
According to the CEN-CENELEC Internal Regulations, the national standards organisations 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, Turkey and the United
Kingdom.
Introduction
This document calls for the use of substances and procedures that could be injurious to health and/or the
environment if adequate precautions are not taken. It refers only to technical suitability: it does not
absolve the user from their legal obligations at any stage.
Protection of the environment is a key political issue in Europe and elsewhere. For CEN/TC 286 this is
covered in CEN/TS 16765 [7] LPG equipment and accessories — Environmental considerations for
CEN/TC 286 standards; which should be read in conjunction with this document. The Technical
Specification provides guidance on the environmental aspects to be considered regarding equipment and
accessories produced for the LPG industry and the following is addressed:
a) design;
b) manufacture;
c) packaging;
d) use and operation;
e) disposal.
It is recommended that manufacturers develop an environmental management policy. For guidance, see
EN ISO 14000 series (see [8], [9] and [10]).
Provisions need to be restricted to a general guidance. Limit values are specified in national laws.
It has been assumed in the drafting of this document that the execution of its provisions is entrusted to
appropriately qualified and experienced people.
All pressures are gauged unless otherwise stated.
NOTE This document requires measurement of material properties, dimensions and pressures. All such
measurements are subject to a degree of uncertainty due to tolerances in measuring equipment, etc. It might be
beneficial to refer to the leaflet “measurement uncertainty leaflet” SP INFO 2000 27 [15].
1 Scope
This document specifies minimum requirements for materials, design, construction and workmanship
procedures, and tests for welded LPG road tanker pressure vessels and their welded attachments
manufactured from carbon, carbon/manganese and micro alloy steels.
There is no upper size limit as this is determined by the gross vehicle weight limitation.
This document does not cover pressure vessels for pressure vessel containers.
NOTE 1 In the context of this document, the term “road tanker” is understood to mean “fixed tanks” and
“demountable tanks” as defined in ADR.
NOTE 2 The equipment for the pressure vessels and the inspection and testing after assembly is covered by
EN 12252 and EN 14334, respectively.
NOTE 3 The design type of the road tanker is subject to approval by the competent authority, as required by
ADR.
NOTE 4 This document is intended for LPG only; however, for other liquefied gases see EN 14025.
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 837-2, Pressure gauges — Part 2: Selection and installation recommendations for pressure gauges
EN 10025-2, Hot rolled products of structural steels — Part 2: Technical delivery conditions for non-alloy
structural steels
EN 10028-2, Flat products made of steels for pressure purposes — Part 2: Non-alloy and alloy steels with
specified elevated temperature properties
EN 10028-3, Flat products made of steels for pressure purposes — Part 3: Weldable fine grain steels,
normalized
EN 10204, Metallic products — Types of inspection documents
EN 12972:2018, Tanks for transport of dangerous goods — Testing, inspection and marking of metallic
tanks
EN 13445-3, Unfired pressure vessels — Part 3: Design
EN 14717, Welding and allied processes — Environmental check list
EN ISO 148-1, Metallic materials — Charpy pendulum impact test — Part 1: Test method (ISO 148-1)
EN ISO 3452-1, Non-destructive testing — Penetrant testing — Part 1: General principles (ISO 3452-1)
EN ISO 3834-2, Quality requirements for fusion welding of metallic materials — Part 2: Comprehensive
quality requirements (ISO 3834-2)
EN ISO 4136, Destructive tests on welds in metallic materials — Transverse tensile test (ISO 4136)
EN ISO 5173, Destructive tests on welds in metallic materials — Bend tests (ISO 5173)
EN ISO 5178, Destructive tests on welds in metallic materials — Longitudinal tensile test on weld metal in
fusion welded joints (ISO 5178)
EN ISO 5579, Non-destructive testing — Radiographic testing of metallic materials using film and X- or
gamma rays — Basic rules (ISO 5579)
EN ISO 5817, Welding — Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding
excluded) — Quality levels for imperfections (ISO 5817)
EN ISO 6520-1, Welding and allied processes — Classification of geometric imperfections in metallic
materials — Part 1: Fusion welding (ISO 6520-1)
EN ISO 6520-2, Welding and allied processes — Classification of geometric imperfections in metallic
materials — Part 2: Welding with pressure (ISO 6520-2)
EN ISO 9016, Destructive tests on welds in metallic materials — Impact tests — Test specimen location,
notch orientation and examination (ISO 9016)
EN ISO 9606-1, Qualification testing of welders — Fusion welding — Part 1: Steels (ISO 9606-1)
EN ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel (ISO 9712)
EN ISO 14732, Welding personnel — Qualification testing of welding operators and weld setters for
mechanized and automatic welding of metallic materials (ISO 14732)
EN ISO 15609-1, Specification and qualification of welding procedures for metallic materials — Welding
procedure specification — Part 1: Arc welding (ISO 15609-1)
EN ISO 15614-1, Specification and qualification of welding procedures for metallic materials — Welding
procedure test — Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys
(ISO 15614-1)
EN ISO 17636-1, Non-destructive testing of welds — Radiographic testing — Part 1: X- and gamma-ray
techniques with film (ISO 17636-1)
EN ISO 17636-2, Non-destructive testing of welds — Radiographic testing — Part 2: X- and gamma-ray
techniques with digital detectors (ISO 17636-2)
EN ISO 17637, Non-destructive testing of welds — Visual testing of fusion-welded joints (ISO 17637)
EN ISO 17638, Non-destructive testing of welds — Magnetic particle testing (ISO 17638)
EN ISO 17639, Destructive tests on welds in metallic materials — Macroscopic and microscopic
examination of welds (ISO 17639)
EN ISO 17640, Non-destructive testing of welds — Ultrasonic testing — Techniques, testing levels, and
assessment (ISO 17640)
EN ISO 19232-1, Non-destructive testing — Image quality of radiographs — Part 1: Determination of the
image quality value using wire-type image quality indicators (ISO 19232-1)
EN ISO 19232-2, Non-destructive testing — Image quality of radiographs — Part 2: Determination of the
image quality value using step/hole-type image quality indicators (ISO 19232-2)
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
liquefied petroleum gas
LPG
low pressure liquefied gas composed of one or more light hydrocarbons which are assigned to UN 1011,
UN 1075, UN 1965, UN 1969 or UN 1978 only and which consists mainly of propane, propene, butane,
butane isomers, butene with traces of other hydrocarbon gases
3.2
yield strength
upper yield strength ReH or, for steels that do not exhibit a definite yield (non-proportional elongation),
the 0,2 % proof strength
3.3
cold forming
forming at temperatures not less than 25 °C below the maximum permissible temperature for stress
relieving, in accordance with the applicable material specifications
3.4
hot forming
forming at temperatures above the temperature for stress relieving as stated in the material
specifications
3.5
sun shield
shield covering not less than the upper third but not more than the upper half of the shell surface,
separated from the shell by an air gap of at least 40 mm
3.6
pressure vessel
assembly of the pressure-retaining envelope (including the openings and their closures) and non-
pressure-retaining parts attached directly to it
Note 1 to entry: Also referred to as “tank” in the ADR.
3.7
competent authority
authority or authorities or any other body or bodies designated as such in each State and in each specific
case in accordance with domestic law
3.8
inspection body
independent inspection and testing body approved by the competent authority
3.9
competent person
person which by combination of appropriate qualification, training, experience, and resources, is able to
make objective judgments on the subject
4 Materials
4.1 Environmental
The manufacturer shall endeavour to acquire materials and components from suppliers who have a
declared environmental policy, see EN ISO 14021, EN ISO 14024 and EN ISO 14025.
4.2 Suitability
4.2.1 Unless otherwise specified by the design documents, the design temperature range shall be
−20 °C to +50 °C.
4.2.2 The materials of construction shall be suitable for operating within the envisaged temperature
range. If the pressure vessel could be subjected to more severe lower ambient or product temperatures,
the design temperature range shall be −40 °C to +50 °C.
4.2.3 Guidance on selection of material grades is given in Annex A.
4.2.4 If additional impact testing is required, it shall be carried out in accordance with EN ISO 148-1 to
achieve the impact values specified in 10.2.5.5.
4.2.5 The materials of the pressure receptacle which are in contact with the contents shall not contain
substances liable to substantially weaken the material. The steel grades specified in EN 10028-2 and
EN 10028-3, listed in Table A.1, are considered compatible with LPG complying with the limitations on
corrosiveness as specified in ISO 9162.
4.3 Pressure retaining parts
Pressure-retaining materials shall be of appropriate steels conforming to EN 10028-2 or EN 10028-3 or
shall conform to specifications agreed with the competent authority. All materials shall conform to 10.2.4
and the ratio of the specified yield strength (R ) to minimum tensile strength (Rm) shall not exceed 0,85
eH
(i.e. R /Rm ≤ 0,85). The percentage elongation at fracture shall be not less than 10 000 divided by the
eH
actual tensile strength in N/mm , and in any case shall be not less than 16 % for fine grained steels and
not less than 20 % for other steels. Where fine grain steels are used, the guaranteed yield strength, R
eH
2 2
shall not exceed 460 N/mm and the upper tensile strength, R , shall not exceed 725 N/mm .
m
4.4 Non-pressure retaining parts
Non-pressure retaining parts that are directly welded to pressure retaining parts shall be of suitable
materials conforming to EN 10025-2 or materials with characteristics approved by a competent
authority. All materials used for non-pressure retaining parts shall be compatible with the material of
pressure retaining parts, and shall conform to the impact requirements of 10.2.5.5, tested in accordance
with the method specified in EN ISO 148-1.
4.5 Welding consumables
Welding consumables shall be able to provide consistent welds with properties at least equal to those
specified for the parent materials in the finished pressure vessel.
4.6 Non-metallic materials (gaskets)
Non-metallic materials (gaskets) shall be compatible with both phases of LPG over the range of pressures
and temperatures for which the road tanker is designed (see 4.2, Annex B and Annex C).
4.7 Inspection documents for materials
Pressure retaining parts and non-pressure retaining parts directly welded to the pressure vessel shall be
provided with the material manufacturers’ certificates conforming to EN 10204 certificate type 3.1. Other
parts shall have certificates conforming to EN 10204 certificate type 2.2.
5 Pressure vessel design
5.1 Design conditions
5.1.1 The reference temperatures shall conform to Annex B. Where it is authorized by a national
competent authority for use within its territory, in accordance with the provision of EU Council Directive
2008/68/EC [13], the reference temperatures designated in Annex C apply.
5.1.2 Design calculations shall be carried out in accordance with Annex D.
5.1.3 Account shall be taken of the fatigue loading on all component parts of the pressure vessel and its
attachments by conducting an assessment or through proven operating experience.
5.1.4 The design of the pressure vessel should take into account the following:
— minimizing the use of materials;
— fittings required for efficient operation of the pressure vessel;
— minimizing the environmental impact of in service maintenance and end of life disposal.
5.2 Minimum thickness
5.2.1 The minimum thickness for pressure vessels not exceeding a diameter of 1,8 m shall be 5 mm of
1)
reference steel or of an equivalent thickness if in a different steel.
5.2.2 For pressure vessels exceeding a diameter of 1,8 m, the minimum thickness shall be 6 mm of
1)
reference steel or of an equivalent thickness if in a different steel.
1)
As defined in ADR.
5.2.3 The equivalent thickness shall be calculated using Formula (1):
464e
e =
RA
( )
m11
(1)
where
A minimum elongation at fracture (%) of steel chosen under tensile stress;
e minimum shell thickness in chosen steel, in mm;
e minimum thickness in reference steel, in mm;
R minimum tensile strength of steel chosen, in N/mm .
m1
5.2.4 The minimum shell thickness shall not be less than the value calculated in accordance with the
1)
following Formula (2) :
P D
T
e= (2)
2σ
where:
e minimum shell thickness
P test pressure in MPa
T
D internal diameter of shell in mm
σ nominal design stress, as calculated in D.1.1
5.3 Surge plates
5.3.1 Where it is intended that pressure vessels will be operated in excess of 20 % full or less than 80 %
full, surge plates shall be fitted. The surge plates shall be designed to permit full internal inspection of the
pressure vessel. The volume between any two plates or a plate and the end of the pressure vessel shall
not exceed 7 500 l.
5.3.2 The distance between surge plates shall not exceed 4 m.
5.3.3 The area of each surge plate shall be at least 70 % of the cross-sectional area of the pressure vessel
in which the plates are fitted.
5.3.4 Surge plates shall be able to withstand the load imposed by a full capacity liquid content of the
section between the plates in either direction.
5.3.5 Surge plates shall be at least 2 mm thick.
5.3.6 Provision shall be made for communication and drainage between sections.
5.4 Doubler plates
To reduce stress concentration on the pressure vessel, load-carrying attachments shall incorporate a
doubler plate between the attachment and the pressure vessel shell.
Non-circular doubler plates shall be designed with as generous as practicable corner radii (minimum
radius 25 mm) to reduce stress concentrations.
Doubler plates shall be provided with vent holes or test sockets which shall be closed after testing.
5.5 Stresses due to motion
Pressure vessels and their permanent attachments shall be able to absorb, under maximum permissible
load, forces exerted by the design pressure, and the following dynamic forces:
— in the direction of travel: twice the total mass;
— at right-angles to the direction of travel: the total mass;
— vertically upwards: the total mass;
— vertically downwards: twice the total mass.
Under the forces defined above, the stresses in the pressure vessel and its fastenings shall not exceed the
following:
a) general membrane stress in the shell, remote from the supports:
— the normal design stress as defined in D.1;
b) stresses local to the supports, determined either by experimental analysis or calculation/special
analysis:
— the limits specified in EN 13445-3.
5.6 Self-supporting pressure vessels
Self-supporting pressure vessels shall be designed to carry bending stresses that would otherwise be
carried by the chassis or frame.
5.7 Vacuum conditions
Pressure vessels shall be designed to withstand vacuum conditions generated by the product during
operation or other operational conditions, but as a minimum, this shall be equivalent to an external
pressure of at least 40 kPa (0,4 bar) gauge pressure.
Suitable design methods may be applied from EN 13445-3.
NOTE Some liquefied petroleum gases have vapour pressures below atmospheric pressure at temperatures
that could occur during normal operations in winter, and this could create partial vacuum conditions within the
carrying pressure vessel.
5.8 Pressure vessel mountings
5.8.1 Mounting structures shall be fabricated in steel and designed to limit movement of the pressure
vessel in relation to the chassis.
5.8.2 Pressure vessel mountings and their method of attachment to the shell shall be of sufficient
strength to support the pressure vessel when full of water.
5.8.3 The design of the pressure vessel mountings shall be coordinated with the design of the vehicle
chassis. The designer shall assess the effect of the pressure vessel and its mountings, including the
additional loadings given in 5.5.
The chassis manufacturer should be notified at the pressure vessel design stage that the pressure vessel,
while on the chassis, could be subjected to a hydraulic test, during which the pressure vessel can contain
twice the normal weight of carrying capacity.
5.8.4 Pressure vessel mountings designed as an integral attachment to the shell shall be fitted with
doubler plates as specified in 5.4. Stitch welding shall not be used.
5.9 Internal pipework
5.9.1 The mechanical strength of internal pipework and supports shall be sufficient to withstand the
service conditions, including dynamic load.
5.9.2 Internal pipework may be attached directly to a pressure vessel boss.
5.9.3 Pipework shall be located so as to avoid inadvertent entry of liquid LPG from the liquid inlet line
into other pipework terminating in the vapour space.
6 Openings
6.1 General
For the equipping of LPG road tankers, see EN 12252.
Valves and other accessories shall be protected against damage by external impact either by their
positioning on the pressure vessel, when mounted on the vehicle, or by specific pressure vessel design.
Provision in pressure vessel design shall be either by mounting and fitting valves and other accessories
in a recess within the contour of the pressure vessel shell or end, or by use of a guard able to withstand a
collision with another vehicle and the forces experienced in a pressure vessel roll-over.
6.2 Reinforcement of openings
Openings shall be reinforced and designed in accordance with D.4.
6.3 Threaded connections
The maximum nominal diameter of threaded connections shall be 80 mm.
6.4 Manhole
6.4.1 Pressure vessels with a volume over 3 000 l shall be fitted with a manhole either:
— at least 500 mm in diameter; or
— at least 420 mm, where reducing the diameter is acceptable to the competent authority.
Pressure vessels with a volume not exceeding 3 000 l may be fitted with inspection openings, instead of
a manhole, with dimensions conforming to EN 286-1.
6.4.2 Manholes shall be of forged construction, machined from plate, or fabricated from pipe and
standard flanges of the appropriate temperature and pressure rating. If plate is used for pad type
manholes, it shall be ultrasonically tested for laminar defects.
6.4.3 The manhole shall be positioned for ease of access.
7 Non-pressure retaining parts
7.1 Attachment welds
Attachment welds shall be continuous.
7.2 Position of attachment welds
Attachments shall be designed not to trap water and to permit inspection of the weld. Wherever possible,
attachment welds shall be clear of vessel welds (longitudinal, circumferential and opening welds), by a
minimum distance of 40 mm. Where this is not possible, attachment welds shall fully cross the main
welds.
8 Workmanship and construction
8.1 General
8.1.1 Road tanker pressure vessels shall be manufactured in accordance with drawings and
specifications approved by a notified/designated inspection body.
8.1.2 The manufacturer shall be responsible for the competence, training and supervision of their staff.
8.1.3 The manufacturer shall ensure, taking into account any instructions from the material supplier
that the materials of the finished pressure vessel conform to this document.
8.1.4 The manufacturer shall have defined procedures for manufacturing operations, including
processes such as forming, welding and heat treatment.
8.2 Environment
8.2.1 The environmental impact of welding and allied processes shall be assessed in accordance with
EN 14717.
8.2.2 The manufacturer should endeavour to minimize wastage of materials by selecting appropriately
sized materials related to the finished parts required for the manufacture. Unavoidable waste/scrap
material should be recycled.
8.2.3 Noise levels from the production process should be evaluated and measures put into place to
minimize the impact upon the external environment.
8.3 Control of materials
8.3.1 The manufacturer of the pressure vessel shall maintain a system of identification for the material
used in the fabrication so that all material for pressure-retaining parts and non-pressure-retaining parts
directly welded to pressure-retaining parts in the completed work can be traced to origin. The system
shall incorporate appropriate procedures for verifying the identity of material received from the supplier.
8.3.2 Verifying procedures shall be based on the material manufacturers’ certificates and/or
acceptance tests. The system shall ensure that before cutting and forming parts of the pressure vessel,
the original identification mark of the material is transferred to any parts of the pressure vessel that could
be without markings after the process. The manufacturer shall ensure that the material conforms to the
design and/or drawings specification.
8.3.3 In laying out and cutting the material:
a) the material identification mark shall be clearly visible when the pressure part is complete; or
b) the manufacturer shall operate a documented system that ensures material traceability for all
materials in the completed pressure vessels.
8.3.4 If the material identification mark is unavoidably cut out during manufacture of a pressure part,
it shall be transferred by the pressure part manufacturer to another part of the component. Transfer of
the mark shall be carried out by a person designated by the manufacturer.
8.3.5 When identification on materials is transferred, the method of marking shall not have any
detrimental effect on the specified material properties.
8.3.6 Details of welding consumables shall be retained.
8.4 Acceptable weld details
8.4.1 The manufacturer, in selecting an appropriate weld detail, shall consider:
— the method of manufacture;
— the service conditions;
— the ability to carry out necessary non-destructive testing.
Recommended weld details are given in EN 1708-1:2010.
The root faces of welding preparations shall be aligned within the tolerances given in the welding
procedure specification.
NOTE Examples of typical welded joints used on the pressure vessel are given in Annex E.
8.4.2 If a pressure vessel is made from more than one shell strake, the longitudinal weld of adjacent
strakes shall be staggered by at least 100 mm between weld edges.
8.4.3 Where the pressure vessel volume is less than 3 000 l and no internal access is provided, joggle
joints are permitted for end to shell joints. Only dished ends shall be joggled.
8.4.4 Joggles shall be sufficiently clear of the knuckle radius to ensure that the edge of the
circumferential weld is at least 12 mm clear of the knuckle.
NOTE A typical joggle joint detail is shown in Figure E.2.
8.5 Heat treatment and forming
8.5.1 Cold forming
8.5.1.1 Heat treatment of cold formed cylindrical shells is not required.
8.5.1.2 Cold formed dished ends shall be heat treated unless the manufacturer can demonstrate that
the properties of the finished products conform to the original design.
8.5.1.3 Cold formed dished ends that have not been heat-treated shall not be welded or heated locally
in the knuckle area to temperatures above 550 °C without subsequent heat treatment.
8.5.2 Hot forming
8.5.2.1 For normalized steels, because of the danger of excessive grain growth, the workpiece
temperature during hot forming shall not exceed 1 050 °C. Before the final stage of hot forming, or if hot
forming is performed only once, the workpiece shall not be heated above 980 °C.
8.5.2.2 The duration of hot forming should be kept to a minimum to avoid grain growth.
8.5.2.3 If no subsequent heat treatment is applied, hot forming shall be completed above 750 °C, or
above 700 °C if the degree of forming in the final stage does not exceed 5 % of the total forming operation.
8.5.2.4 Cooling shall be carried out in still air.
8.5.2.5 If hot forming is carried out in conditions other than those specified in this subclause,
normalizing as specified by the steel manufacturer or supplier shall be carried out after hot forming.
8.5.2.6 A competent person shall specify the heat treatment procedure to ensure that the properties
of the finished product conform to the original design.
8.5.2.7 The hot forming process should be designed to minimize energy consumption and ensure the
environmentally friendly disposal of insulating material and other waste.
8.5.3 Testing of formed parts
8.5.3.1 For cold-formed parts not subject to heat treatment, no mechanical tests are required in
respect of the forming operation.
8.5.3.2 All other formed parts shall have tests carried out after the last forming operation or any heat
treatment to demonstrate conformity to the material specification. Test pieces shall be taken from an
excess length or a redundant piece of the formed part, or from a separate test piece formed to same
procedure. The test pieces shall consist of one tensile and three impact specimens.
8.5.3.3 In the case of formed ends, the test pieces shall be taken from sample ends selected as follows:
— from initial production: one from ten of each family; and
— from production formed ends: one formed part in 1 000 production units, but not less than one per
two years.
8.5.3.4 Ends with the following characteristics are considered to be a family of ends:
— same material specification;
— same forming process;
— same heat treatment;
— geometrical similarity to ± 10 %.
8.5.4 Visual examination and control of dimensions
Bought-in formed parts that require acceptance certificates conforming to EN 10204 shall be submitted
by the pressure vessel manufacturer to visual examination and dimensional check in the delivery
condition, and the results shall be included in the pressure vessel acceptance certificate.
8.5.5 Marking
Formed parts of pressure vessels shall be marked so that the material and the manufacturer of the part
can be identified as specified in 8.3. For batch testing the relationship to the batch shall be evident.
8.6 Welding
8.6.1 General
Welding of the joints of the component parts of a pressure vessel shall conform to EN ISO 3834-2 and
shall only be carried out if all the following apply:
a) a welding procedure specification is compiled by the manufacturer;
b) the welding procedures selected by the manufacturer are qualified for the field of application. If the
design is based on material specifications agreed by an inspection body, the welding procedure shall
be qualified using material with the higher properties;
c) the welders and
...
SLOVENSKI STANDARD
01-februar-2021
Nadomešča:
SIST EN 12493:2013+A2:2018
Oprema in pribor za utekočinjeni naftni plin (UNP) - Varjene tlačne posode cestnih
cistern iz jekla za UNP - Konstruiranje in izdelava
LPG equipment and accessories - Welded steel pressure vessels for LPG road tankers -
Design and manufacture
Flüssiggas-Geräte und Ausrüstungsteile - Geschweißte Druckbehälter aus Stahl für
Straßentankwagen für Flüssiggas (LPG) - Auslegung und Herstellung
Équipements pour GPL et leurs accessoires - Réservoirs sous pression en acier soudés
des camions-citernes pour GPL - Conception et construction
Ta slovenski standard je istoveten z: EN 12493:2020
ICS:
23.020.35 Plinske jeklenke Gas cylinders
43.080.10 Tovornjaki in priklopniki Trucks and trailers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 12493
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2020
EUROPÄISCHE NORM
ICS 23.020.30; 23.020.35 Supersedes EN 12493:2013+A2:2018
English Version
LPG equipment and accessories - Welded steel pressure
vessels for LPG road tankers - Design and manufacture
Équipements pour GPL et leurs accessoires - Flüssiggas-Geräte und Ausrüstungsteile - Geschweißte
Réservoirs sous pression en acier soudés des camions - Druckbehälter aus Stahl für Straßentankwagen für
Conception et construction Flüssiggas (LPG) - Auslegung und Herstellung
This European Standard was approved by CEN on 16 November 2020.
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, 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
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 12493:2020 E
worldwide for CEN national Members.
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 8
4 Materials . 9
4.1 Environmental. 9
4.2 Suitability . 9
4.3 Pressure retaining parts . 9
4.4 Non-pressure retaining parts . 9
4.5 Welding consumables . 9
4.6 Non-metallic materials (gaskets) . 10
4.7 Inspection documents for materials . 10
5 Pressure vessel design . 10
5.1 Design conditions . 10
5.2 Minimum thickness . 10
5.3 Surge plates . 11
5.4 Doubler plates . 12
5.5 Stresses due to motion . 12
5.6 Self-supporting pressure vessels. 12
5.7 Vacuum conditions . 12
5.8 Pressure vessel mountings . 12
5.9 Internal pipework . 13
6 Openings . 13
6.1 General . 13
6.2 Reinforcement of openings. 13
6.3 Threaded connections . 13
6.4 Manhole . 13
7 Non-pressure retaining parts . 14
7.1 Attachment welds . 14
7.2 Position of attachment welds . 14
8 Workmanship and construction . 14
8.1 General . 14
8.2 Environment . 14
8.3 Control of materials. 14
8.4 Acceptable weld details . 15
8.5 Heat treatment and forming . 15
8.6 Welding . 17
8.7 Repairs to pressure envelope and direct attachment welds . 19
9 Construction and workmanship of internal pipework . 19
10 Manufacturing tests and examinations . 19
10.1 General . 19
10.2 Mechanical testing . 20
10.3 Non-destructive testing . 21
10.4 Non-destructive testing for welds . 21
10.5 Qualification of non-destructive testing personnel . 22
10.6 Visual examination of welds . 22
10.7 Acceptance criteria . 23
10.8 Safety precautions at the hydraulic test . 23
11 External corrosion protection and finishing . 23
11.1 External protection . 23
11.2 Finishing operations . 23
12 Marking . 23
13 Records and documentation . 23
13.1 Documentation obtained by the manufacturer . 23
13.2 Records prepared by the manufacturer . 23
13.3 Retention and supply of documents . 24
Annex A (normative) Guidance on selection of materials grades . 25
Annex B (normative) Reference temperatures for design . 26
Annex C (informative) Alternative reference temperatures for design . 27
Annex D (normative) Design . 28
Annex E (informative) Example of joints . 43
Annex F (normative) Allowable tolerances . 47
Annex G (normative) Heat treatment . 52
Annex H (informative) Typical method for measurement of shell peaking . 53
Annex I (informative) Choice of non-destructive test methods for welds . 56
Annex J (normative) Hydraulic pressure test . 57
Bibliography . 58
European foreword
This document (EN 12493:2020) has been prepared by Technical Committee /TC 286 “LPG equipment
and accessories”, the secretariat of which is held by NSAI.
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 June 2021, and conflicting national standards shall be
withdrawn at the latest by June 2021.
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 12493:2013+A2:2018.
The following main changes have been introduced during this revision:
— removal of Annex I, Welding imperfections and test specimens;
— addition of normative reference to EN 12972.
This document has been submitted for reference in:
— the RID and/or;
— the technical annexes of the ADR.
NOTE These regulations take precedence over any clause of this document. It is emphasized that
RID/ADR are being revised regularly at intervals of two years which may lead to temporary non-
compliances with the clauses of this document.
According to the CEN-CENELEC Internal Regulations, the national standards organisations 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, Turkey and the United
Kingdom.
Introduction
This document calls for the use of substances and procedures that could be injurious to health and/or the
environment if adequate precautions are not taken. It refers only to technical suitability: it does not
absolve the user from their legal obligations at any stage.
Protection of the environment is a key political issue in Europe and elsewhere. For CEN/TC 286 this is
covered in CEN/TS 16765 [7] LPG equipment and accessories — Environmental considerations for
CEN/TC 286 standards; which should be read in conjunction with this document. The Technical
Specification provides guidance on the environmental aspects to be considered regarding equipment and
accessories produced for the LPG industry and the following is addressed:
a) design;
b) manufacture;
c) packaging;
d) use and operation;
e) disposal.
It is recommended that manufacturers develop an environmental management policy. For guidance, see
EN ISO 14000 series (see [8], [9] and [10]).
Provisions need to be restricted to a general guidance. Limit values are specified in national laws.
It has been assumed in the drafting of this document that the execution of its provisions is entrusted to
appropriately qualified and experienced people.
All pressures are gauged unless otherwise stated.
NOTE This document requires measurement of material properties, dimensions and pressures. All such
measurements are subject to a degree of uncertainty due to tolerances in measuring equipment, etc. It might be
beneficial to refer to the leaflet “measurement uncertainty leaflet” SP INFO 2000 27 [15].
1 Scope
This document specifies minimum requirements for materials, design, construction and workmanship
procedures, and tests for welded LPG road tanker pressure vessels and their welded attachments
manufactured from carbon, carbon/manganese and micro alloy steels.
There is no upper size limit as this is determined by the gross vehicle weight limitation.
This document does not cover pressure vessels for pressure vessel containers.
NOTE 1 In the context of this document, the term “road tanker” is understood to mean “fixed tanks” and
“demountable tanks” as defined in ADR.
NOTE 2 The equipment for the pressure vessels and the inspection and testing after assembly is covered by
EN 12252 and EN 14334, respectively.
NOTE 3 The design type of the road tanker is subject to approval by the competent authority, as required by
ADR.
NOTE 4 This document is intended for LPG only; however, for other liquefied gases see EN 14025.
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 837-2, Pressure gauges — Part 2: Selection and installation recommendations for pressure gauges
EN 10025-2, Hot rolled products of structural steels — Part 2: Technical delivery conditions for non-alloy
structural steels
EN 10028-2, Flat products made of steels for pressure purposes — Part 2: Non-alloy and alloy steels with
specified elevated temperature properties
EN 10028-3, Flat products made of steels for pressure purposes — Part 3: Weldable fine grain steels,
normalized
EN 10204, Metallic products — Types of inspection documents
EN 12972:2018, Tanks for transport of dangerous goods — Testing, inspection and marking of metallic
tanks
EN 13445-3, Unfired pressure vessels — Part 3: Design
EN 14717, Welding and allied processes — Environmental check list
EN ISO 148-1, Metallic materials — Charpy pendulum impact test — Part 1: Test method (ISO 148-1)
EN ISO 3452-1, Non-destructive testing — Penetrant testing — Part 1: General principles (ISO 3452-1)
EN ISO 3834-2, Quality requirements for fusion welding of metallic materials — Part 2: Comprehensive
quality requirements (ISO 3834-2)
EN ISO 4136, Destructive tests on welds in metallic materials — Transverse tensile test (ISO 4136)
EN ISO 5173, Destructive tests on welds in metallic materials — Bend tests (ISO 5173)
EN ISO 5178, Destructive tests on welds in metallic materials — Longitudinal tensile test on weld metal in
fusion welded joints (ISO 5178)
EN ISO 5579, Non-destructive testing — Radiographic testing of metallic materials using film and X- or
gamma rays — Basic rules (ISO 5579)
EN ISO 5817, Welding — Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding
excluded) — Quality levels for imperfections (ISO 5817)
EN ISO 6520-1, Welding and allied processes — Classification of geometric imperfections in metallic
materials — Part 1: Fusion welding (ISO 6520-1)
EN ISO 6520-2, Welding and allied processes — Classification of geometric imperfections in metallic
materials — Part 2: Welding with pressure (ISO 6520-2)
EN ISO 9016, Destructive tests on welds in metallic materials — Impact tests — Test specimen location,
notch orientation and examination (ISO 9016)
EN ISO 9606-1, Qualification testing of welders — Fusion welding — Part 1: Steels (ISO 9606-1)
EN ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel (ISO 9712)
EN ISO 14732, Welding personnel — Qualification testing of welding operators and weld setters for
mechanized and automatic welding of metallic materials (ISO 14732)
EN ISO 15609-1, Specification and qualification of welding procedures for metallic materials — Welding
procedure specification — Part 1: Arc welding (ISO 15609-1)
EN ISO 15614-1, Specification and qualification of welding procedures for metallic materials — Welding
procedure test — Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys
(ISO 15614-1)
EN ISO 17636-1, Non-destructive testing of welds — Radiographic testing — Part 1: X- and gamma-ray
techniques with film (ISO 17636-1)
EN ISO 17636-2, Non-destructive testing of welds — Radiographic testing — Part 2: X- and gamma-ray
techniques with digital detectors (ISO 17636-2)
EN ISO 17637, Non-destructive testing of welds — Visual testing of fusion-welded joints (ISO 17637)
EN ISO 17638, Non-destructive testing of welds — Magnetic particle testing (ISO 17638)
EN ISO 17639, Destructive tests on welds in metallic materials — Macroscopic and microscopic
examination of welds (ISO 17639)
EN ISO 17640, Non-destructive testing of welds — Ultrasonic testing — Techniques, testing levels, and
assessment (ISO 17640)
EN ISO 19232-1, Non-destructive testing — Image quality of radiographs — Part 1: Determination of the
image quality value using wire-type image quality indicators (ISO 19232-1)
EN ISO 19232-2, Non-destructive testing — Image quality of radiographs — Part 2: Determination of the
image quality value using step/hole-type image quality indicators (ISO 19232-2)
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
liquefied petroleum gas
LPG
low pressure liquefied gas composed of one or more light hydrocarbons which are assigned to UN 1011,
UN 1075, UN 1965, UN 1969 or UN 1978 only and which consists mainly of propane, propene, butane,
butane isomers, butene with traces of other hydrocarbon gases
3.2
yield strength
upper yield strength ReH or, for steels that do not exhibit a definite yield (non-proportional elongation),
the 0,2 % proof strength
3.3
cold forming
forming at temperatures not less than 25 °C below the maximum permissible temperature for stress
relieving, in accordance with the applicable material specifications
3.4
hot forming
forming at temperatures above the temperature for stress relieving as stated in the material
specifications
3.5
sun shield
shield covering not less than the upper third but not more than the upper half of the shell surface,
separated from the shell by an air gap of at least 40 mm
3.6
pressure vessel
assembly of the pressure-retaining envelope (including the openings and their closures) and non-
pressure-retaining parts attached directly to it
Note 1 to entry: Also referred to as “tank” in the ADR.
3.7
competent authority
authority or authorities or any other body or bodies designated as such in each State and in each specific
case in accordance with domestic law
3.8
inspection body
independent inspection and testing body approved by the competent authority
3.9
competent person
person which by combination of appropriate qualification, training, experience, and resources, is able to
make objective judgments on the subject
4 Materials
4.1 Environmental
The manufacturer shall endeavour to acquire materials and components from suppliers who have a
declared environmental policy, see EN ISO 14021, EN ISO 14024 and EN ISO 14025.
4.2 Suitability
4.2.1 Unless otherwise specified by the design documents, the design temperature range shall be
−20 °C to +50 °C.
4.2.2 The materials of construction shall be suitable for operating within the envisaged temperature
range. If the pressure vessel could be subjected to more severe lower ambient or product temperatures,
the design temperature range shall be −40 °C to +50 °C.
4.2.3 Guidance on selection of material grades is given in Annex A.
4.2.4 If additional impact testing is required, it shall be carried out in accordance with EN ISO 148-1 to
achieve the impact values specified in 10.2.5.5.
4.2.5 The materials of the pressure receptacle which are in contact with the contents shall not contain
substances liable to substantially weaken the material. The steel grades specified in EN 10028-2 and
EN 10028-3, listed in Table A.1, are considered compatible with LPG complying with the limitations on
corrosiveness as specified in ISO 9162.
4.3 Pressure retaining parts
Pressure-retaining materials shall be of appropriate steels conforming to EN 10028-2 or EN 10028-3 or
shall conform to specifications agreed with the competent authority. All materials shall conform to 10.2.4
and the ratio of the specified yield strength (R ) to minimum tensile strength (Rm) shall not exceed 0,85
eH
(i.e. R /Rm ≤ 0,85). The percentage elongation at fracture shall be not less than 10 000 divided by the
eH
actual tensile strength in N/mm , and in any case shall be not less than 16 % for fine grained steels and
not less than 20 % for other steels. Where fine grain steels are used, the guaranteed yield strength, R
eH
2 2
shall not exceed 460 N/mm and the upper tensile strength, R , shall not exceed 725 N/mm .
m
4.4 Non-pressure retaining parts
Non-pressure retaining parts that are directly welded to pressure retaining parts shall be of suitable
materials conforming to EN 10025-2 or materials with characteristics approved by a competent
authority. All materials used for non-pressure retaining parts shall be compatible with the material of
pressure retaining parts, and shall conform to the impact requirements of 10.2.5.5, tested in accordance
with the method specified in EN ISO 148-1.
4.5 Welding consumables
Welding consumables shall be able to provide consistent welds with properties at least equal to those
specified for the parent materials in the finished pressure vessel.
4.6 Non-metallic materials (gaskets)
Non-metallic materials (gaskets) shall be compatible with both phases of LPG over the range of pressures
and temperatures for which the road tanker is designed (see 4.2, Annex B and Annex C).
4.7 Inspection documents for materials
Pressure retaining parts and non-pressure retaining parts directly welded to the pressure vessel shall be
provided with the material manufacturers’ certificates conforming to EN 10204 certificate type 3.1. Other
parts shall have certificates conforming to EN 10204 certificate type 2.2.
5 Pressure vessel design
5.1 Design conditions
5.1.1 The reference temperatures shall conform to Annex B. Where it is authorized by a national
competent authority for use within its territory, in accordance with the provision of EU Council Directive
2008/68/EC [13], the reference temperatures designated in Annex C apply.
5.1.2 Design calculations shall be carried out in accordance with Annex D.
5.1.3 Account shall be taken of the fatigue loading on all component parts of the pressure vessel and its
attachments by conducting an assessment or through proven operating experience.
5.1.4 The design of the pressure vessel should take into account the following:
— minimizing the use of materials;
— fittings required for efficient operation of the pressure vessel;
— minimizing the environmental impact of in service maintenance and end of life disposal.
5.2 Minimum thickness
5.2.1 The minimum thickness for pressure vessels not exceeding a diameter of 1,8 m shall be 5 mm of
1)
reference steel or of an equivalent thickness if in a different steel.
5.2.2 For pressure vessels exceeding a diameter of 1,8 m, the minimum thickness shall be 6 mm of
1)
reference steel or of an equivalent thickness if in a different steel.
1)
As defined in ADR.
5.2.3 The equivalent thickness shall be calculated using Formula (1):
464e
e =
RA
( )
m11
(1)
where
A minimum elongation at fracture (%) of steel chosen under tensile stress;
e minimum shell thickness in chosen steel, in mm;
e minimum thickness in reference steel, in mm;
R minimum tensile strength of steel chosen, in N/mm .
m1
5.2.4 The minimum shell thickness shall not be less than the value calculated in accordance with the
1)
following Formula (2) :
P D
T
e= (2)
2σ
where:
e minimum shell thickness
P test pressure in MPa
T
D internal diameter of shell in mm
σ nominal design stress, as calculated in D.1.1
5.3 Surge plates
5.3.1 Where it is intended that pressure vessels will be operated in excess of 20 % full or less than 80 %
full, surge plates shall be fitted. The surge plates shall be designed to permit full internal inspection of the
pressure vessel. The volume between any two plates or a plate and the end of the pressure vessel shall
not exceed 7 500 l.
5.3.2 The distance between surge plates shall not exceed 4 m.
5.3.3 The area of each surge plate shall be at least 70 % of the cross-sectional area of the pressure vessel
in which the plates are fitted.
5.3.4 Surge plates shall be able to withstand the load imposed by a full capacity liquid content of the
section between the plates in either direction.
5.3.5 Surge plates shall be at least 2 mm thick.
5.3.6 Provision shall be made for communication and drainage between sections.
5.4 Doubler plates
To reduce stress concentration on the pressure vessel, load-carrying attachments shall incorporate a
doubler plate between the attachment and the pressure vessel shell.
Non-circular doubler plates shall be designed with as generous as practicable corner radii (minimum
radius 25 mm) to reduce stress concentrations.
Doubler plates shall be provided with vent holes or test sockets which shall be closed after testing.
5.5 Stresses due to motion
Pressure vessels and their permanent attachments shall be able to absorb, under maximum permissible
load, forces exerted by the design pressure, and the following dynamic forces:
— in the direction of travel: twice the total mass;
— at right-angles to the direction of travel: the total mass;
— vertically upwards: the total mass;
— vertically downwards: twice the total mass.
Under the forces defined above, the stresses in the pressure vessel and its fastenings shall not exceed the
following:
a) general membrane stress in the shell, remote from the supports:
— the normal design stress as defined in D.1;
b) stresses local to the supports, determined either by experimental analysis or calculation/special
analysis:
— the limits specified in EN 13445-3.
5.6 Self-supporting pressure vessels
Self-supporting pressure vessels shall be designed to carry bending stresses that would otherwise be
carried by the chassis or frame.
5.7 Vacuum conditions
Pressure vessels shall be designed to withstand vacuum conditions generated by the product during
operation or other operational conditions, but as a minimum, this shall be equivalent to an external
pressure of at least 40 kPa (0,4 bar) gauge pressure.
Suitable design methods may be applied from EN 13445-3.
NOTE Some liquefied petroleum gases have vapour pressures below atmospheric pressure at temperatures
that could occur during normal operations in winter, and this could create partial vacuum conditions within the
carrying pressure vessel.
5.8 Pressure vessel mountings
5.8.1 Mounting structures shall be fabricated in steel and designed to limit movement of the pressure
vessel in relation to the chassis.
5.8.2 Pressure vessel mountings and their method of attachment to the shell shall be of sufficient
strength to support the pressure vessel when full of water.
5.8.3 The design of the pressure vessel mountings shall be coordinated with the design of the vehicle
chassis. The designer shall assess the effect of the pressure vessel and its mountings, including the
additional loadings given in 5.5.
The chassis manufacturer should be notified at the pressure vessel design stage that the pressure vessel,
while on the chassis, could be subjected to a hydraulic test, during which the pressure vessel can contain
twice the normal weight of carrying capacity.
5.8.4 Pressure vessel mountings designed as an integral attachment to the shell shall be fitted with
doubler plates as specified in 5.4. Stitch welding shall not be used.
5.9 Internal pipework
5.9.1 The mechanical strength of internal pipework and supports shall be sufficient to withstand the
service conditions, including dynamic load.
5.9.2 Internal pipework may be attached directly to a pressure vessel boss.
5.9.3 Pipework shall be located so as to avoid inadvertent entry of liquid LPG from the liquid inlet line
into other pipework terminating in the vapour space.
6 Openings
6.1 General
For the equipping of LPG road tankers, see EN 12252.
Valves and other accessories shall be protected against damage by external impact either by their
positioning on the pressure vessel, when mounted on the vehicle, or by specific pressure vessel design.
Provision in pressure vessel design shall be either by mounting and fitting valves and other accessories
in a recess within the contour of the pressure vessel shell or end, or by use of a guard able to withstand a
collision with another vehicle and the forces experienced in a pressure vessel roll-over.
6.2 Reinforcement of openings
Openings shall be reinforced and designed in accordance with D.4.
6.3 Threaded connections
The maximum nominal diameter of threaded connections shall be 80 mm.
6.4 Manhole
6.4.1 Pressure vessels with a volume over 3 000 l shall be fitted with a manhole either:
— at least 500 mm in diameter; or
— at least 420 mm, where reducing the diameter is acceptable to the competent authority.
Pressure vessels with a volume not exceeding 3 000 l may be fitted with inspection openings, instead of
a manhole, with dimensions conforming to EN 286-1.
6.4.2 Manholes shall be of forged construction, machined from plate, or fabricated from pipe and
standard flanges of the appropriate temperature and pressure rating. If plate is used for pad type
manholes, it shall be ultrasonically tested for laminar defects.
6.4.3 The manhole shall be positioned for ease of access.
7 Non-pressure retaining parts
7.1 Attachment welds
Attachment welds shall be continuous.
7.2 Position of attachment welds
Attachments shall be designed not to trap water and to permit inspection of the weld. Wherever possible,
attachment welds shall be clear of vessel welds (longitudinal, circumferential and opening welds), by a
minimum distance of 40 mm. Where this is not possible, attachment welds shall fully cross the main
welds.
8 Workmanship and construction
8.1 General
8.1.1 Road tanker pressure vessels shall be manufactured in accordance with drawings and
specifications approved by a notified/designated inspection body.
8.1.2 The manufacturer shall be responsible for the competence, training and supervision of their staff.
8.1.3 The manufacturer shall ensure, taking into account any instructions from the material supplier
that the materials of the finished pressure vessel conform to this document.
8.1.4 The manufacturer shall have defined procedures for manufacturing operations, including
processes such as forming, welding and heat treatment.
8.2 Environment
8.2.1 The environmental impact of welding and allied processes shall be assessed in accordance with
EN 14717.
8.2.2 The manufacturer should endeavour to minimize wastage of materials by selecting appropriately
sized materials related to the finished parts required for the manufacture. Unavoidable waste/scrap
material should be recycled.
8.2.3 Noise levels from the production process should be evaluated and measures put into place to
minimize the impact upon the external environment.
8.3 Control of materials
8.3.1 The manufacturer of the pressure vessel shall maintain a system of identification for the material
used in the fabrication so that all material for pressure-retaining parts and non-pressure-retaining parts
directly welded to pressure-retaining parts in the completed work can be traced to origin. The system
shall incorporate appropriate procedures for verifying the identity of material received from the supplier.
8.3.2 Verifying procedures shall be based on the material manufacturers’ certificates and/or
acceptance tests. The system shall ensure that before cutting and forming parts of the pressure vessel,
the original identification mark of the material is transferred to any parts of the pressure vessel that could
be without markings after the process. The manufacturer shall ensure that the material conforms to the
design and/or drawings specification.
8.3.3 In laying out and cutting the material:
a) the material identification mark shall be clearly visible when the pressure part is complete; or
b) the manufacturer shall operate a documented system that ensures material traceability for all
materials in the completed pressure vessels.
8.3.4 If the material identification mark is unavoidably cut out during manufacture of a pressure part,
it shall be transferred by the pressure part manufacturer to another part of the component. Transfer of
the mark shall be carried out by a person designated by the manufacturer.
8.3.5 When identification on materials is transferred, the method of marking shall not have any
detrimental effect on the specified material properties.
8.3.6 Details of welding consumables shall be retained.
8.4 Acceptable weld details
8.4.1 The manufacturer, in selecting an appropriate weld detail, shall consider:
— the method of manufacture;
— the service conditions;
— the ability to carry out necessary non-destructive testing.
Recommended weld details are given in EN 1708-1:2010.
The root faces of welding preparations shall be aligned within the tolerances given in the welding
procedure specification.
NOTE Examples of typical welded joints used on the pressure vessel are given in Annex E.
8.4.2 If a pressure vessel is made from more than one shell strake, the longitudinal weld of adjacent
strakes shall be staggered by at least 100 mm between weld edges.
8.4.3 Where the pressure vessel volume is less than 3 000 l and no internal access is provided, joggle
joints are permitted for end to shell joints. Only dished ends shall be joggled.
8.4.4 Joggles shall be sufficiently clear of the knuckle radius to ensure that the edge of the
circumferential weld is at least 12 mm clear of the knuckle.
NOTE A typical joggle joint detail is shown in Figure E.2.
8.5 Heat treatment and forming
8.5.1 Cold forming
8.5.1.1 Heat treatment of cold formed cylindrical shells is not required.
8.5.1.2 Cold formed dished ends shall be heat treated unless the manufacturer can demonstrate that
the properties of the finished products conform to the original design.
8.5.1.3 Cold formed dished ends that have not been heat-treated shall not be welded or heated locally
in the knuckle area to temperatures above 550 °C without subsequent heat treatment.
8.5.2 Hot forming
8.5.2.1 For normalized steels, because of the danger of excessive grain growth, the workpiece
temperature during hot forming shall not exceed 1 050 °C. Before the final stage of hot forming, or if hot
forming is performed only once, the workpiece shall not be heated above 980 °C.
8.5.2.2 The duration of hot forming should be kept to a minimum to avoid grain growth.
8.5.2.3 If no subsequent heat treatment is applied, hot forming shall be completed above 750 °C, or
above 700 °C if the degree of forming in the final stage does not exceed 5 % of the total forming operation.
8.5.2.4 Cooling shall be carried out in still air.
8.5.2.5 If hot forming is carried out in conditions other than those specified in this subclause,
normalizing as specified by the steel manufacturer or supplier shall be carried out after hot forming.
8.5.2.6 A competent person shall specify the heat treatment procedure to ensure that the properties
of the finished product conform to the original design.
8.5.2.7 The hot forming process should be designed to minimize energy consumption and ensure the
environmentally friendly disposal of insulating material and other waste.
8.5.3 Testing of formed parts
8.5.3.1 For cold-formed parts not subject to heat treatment, no mechanical tests are required in
respect of the forming operation.
8.5.3.2 All other formed parts shall have tests carried out after the last forming operation or any heat
treatment to demonstrate conformity to the material specification. Test pieces shall be taken from an
excess length or a redundant piece of the formed part, or from a separate test piece formed to same
procedure. The test pieces shall consist of one tensile and three impact specimens.
8.5.3.3 In the case of formed ends, the test pieces shall be taken from sample ends selected as follows:
— from initial production: one from ten of each family; and
— from production formed ends: one formed part in 1 000 production units, but not less than one per
two years.
8.5.3.4 Ends with the following characteristics are considered to be a family of ends:
— same material specification;
— same forming process;
— same heat treatment;
— geometrical similarity to ± 10 %.
8.5.4 Visual examination and control of dimensions
Bought-in formed parts that require acceptance certificates conforming to EN 10204 shall be submitted
by the pressure vessel manufacturer to visual examination and dimensional check in the delivery
condition, and the results shall be included in the pressure vessel acceptance certificate.
8.5.5 Marking
Formed parts of pressure vessels shall be marked so that the material and the manufacturer of the part
can be identified as specified in 8.3. For batch testing the relationship to the batch shall be evident.
8.6 Welding
8.6.1 General
Welding of the joints of the component parts of a pressure vessel shall conform to EN ISO 3834-2 and
shall only be carried out if all the following apply:
a) a welding procedure specification is compiled by the manufacturer;
b) the welding procedures selected by the manufacturer are qualified for the field of application. If the
design is based on material specifications agreed by an inspection body, the welding procedure shall
be qualified using material with the higher properties;
c) the welders and we
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