EN ISO 9809-1:2010

SLOVENSKI STANDARD
01-november-2010
1DGRPHãþD
SIST EN 1964-1:1999
SIST EN 1964-1:1999/AC:2001
Plinske jeklenke - Ponovno polnljive plinske jeklenke iz celega, iz jekla -
Konstruiranje, izdelava in preskus - 1. del: Jeklenke iz jekel za poboljšanje z
natezno trdnostjo, manjšo od 1100 MPa (ISO 9809-1:2010)
Gas cylinders - Refillable seamless steel gas cylinders - Design, construction and testing
- Part 1: Quenched and tempered steel cylinders with tensile strength less than 1 100
MPa (ISO 9809-1:2010)
Gasflaschen - Wiederbefüllbare nahtlose Gasflaschen aus Stahl - Gestaltung,
Konstruktion und Prüfung - Teil 1: Flaschen aus vergütetem Stahl mit einer Zugfestigkeit
kleiner als 1 100 MPa (ISO 9809-1:2010)
Bouteilles à gaz - Bouteilles à gaz rechargeables en acier sans soudure - Conception,
construction et essais - Partie 1: Bouteilles en acier trempé et revenu ayant une
résistance à la traction inférieure à 1 100 MPa (ISO 9809-1:2010)
Ta slovenski standard je istoveten z: EN ISO 9809-1:2010
ICS:
23.020.30 7ODþQHSRVRGHSOLQVNH Pressure vessels, gas
MHNOHQNH cylinders
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 9809-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2010
ICS 23.020.30 Supersedes EN 1964-1:1999
English Version
Gas cylinders - Refillable seamless steel gas cylinders - Design,
construction and testing - Part 1: Quenched and tempered steel
cylinders with tensile strength less than 1 100 MPa (ISO 9809-
1:2010)
Bouteilles à gaz - Bouteilles à gaz rechargeables en acier Gasflaschen - Wiederbefüllbare nahtlose Gasflaschen aus
sans soudure - Conception, construction et essais - Partie Stahl - Gestaltung, Konstruktion und Prüfung - Teil 1:
1: Bouteilles en acier trempé et revenu ayant une Flaschen aus vergütetem Stahl mit einer Zugfestigkeit
résistance à la traction inférieure à 1 100 MPa (ISO 9809- kleiner als 1 100 MPa (ISO 9809-1:2010)
1:2010)
This European Standard was approved by CEN on 18 March 2010.

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 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 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, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 9809-1:2010: E
worldwide for CEN national Members.

Contents Page
Foreword .3
Annex NA (normative) Specific European requirements .4

Foreword
This document (EN ISO 9809-1:2010) has been prepared by Technical Committee ISO/TC 58 "Gas cylinders"
in collaboration with Technical Committee CEN/TC 23 “Transportable gas cylinders”, the secretariat of which
is held by BSI.
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 October 2010, and conflicting national standards shall be withdrawn at
the latest by October 2010.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 1964-1:1999.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association, and supports essential requirements of EU Directive(s).
For Specific European requirements, see normative Annex NA, which is an integral part of this document.
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, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 9809-1:2010 has been approved by CEN as a EN ISO 9809-1:2010 without any modification.
Annex NA
(normative)
Specific European requirements
NA.1 Normative references
The following referenced documents are indispensable for the application 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 473, Non-destructive testing — Qualification and certification of NDT personnel — General principles

EN ISO 11114-4, Transportable gas cylinders — Compatibility of cylinder and valve materials with gas
contents — Part 4: Test methods for selecting metallic materials resistant to hydrogen embrittlement

EN ISO 13769, Gas cylinders — Stamp marking

NA.2 Technical requirements
With reference to the clauses in the main body of the text, the following additional requirements shall apply:
5 Inspection and testing
The following informative note shall be added to Clause 5:
“NOTE The conformity of cylinders shall be assessed in accordance with the regulations in force at the time of
manufacture. RID/ADR/ADN includes requirements for conformity assessment consisting of type approval, supervision of
manufacture and initial inspection and test. If conformity is assessed in accordance with Council Directive 99/36/EC on
transportable pressure equipment (TPED), modules B+D or B+F should be used. If other modules are used, the cylinders
will not be in conformity with this standard and the number of this standard shall not be marked.”

11.2 Hydraulic test
11.2.2 Volumetric expansion test
"NOTE The initial inspection and tests regarding hydraulic test are regulated by RID, ADR which take precedence over
Clause 11.2.2.
13 Marking
Marking shall be in accordance with EN ISO 13769.
"NOTE The marking of gas cylinders is regulated by RID, ADR and ADN which take precedence over any clause in this
standard. The European Directive on the TPED includes additional marking requirements (π-marking). It is important to
know that these provisions are subject to regular revisions. This may lead to temporary noncompliance with EN ISO
13769.”
Annex A
Annex A shall be taken as normative.

B.2 General requirements
The second paragraph shall be replaced by the following: “The operation of the test equipment shall be by
personnel certified at least to level 1 of EN 473 and supervised by qualified and experienced personnel
certified to level 2 or level 3 of EN 473.
Additionally the following note shall be added to the end of this clause:
"NOTE As it is considered that the qualifications of personnel according to EN 473 and ISO 9712 are comparable,
certification of the personnel to either standard should be accepted.”

INTERNATIONAL ISO
STANDARD 9809-1
Second edition
2010-04-15
Gas cylinders — Refillable seamless steel
gas cylinders — Design, construction and
testing —
Part 1:
Quenched and tempered steel cylinders
with tensile strength less than 1 100 MPa
Bouteilles à gaz — Bouteilles à gaz rechargeables en acier sans
soudure — Conception, construction et essais —
Partie 1: Bouteilles en acier trempé et revenu ayant une résistance à la
traction inférieure à 1 100 MPa

Reference number
ISO 9809-1:2010(E)
©
ISO 2010
ISO 9809-1:2010(E)
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ii © ISO 2010 – All rights reserved

ISO 9809-1:2010(E)
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Terms and definitions .2
4 Symbols.2
5 Inspection and testing .3
6 Materials .4
7 Design.7
8 Construction and workmanship .11
9 Type approval procedure.13
10 Batch tests .15
11 Tests/examinations on every cylinder .24
12 Certification.25
13 Marking.25
Annex A (informative) Description and evaluation of manufacturing imperfections and conditions
for rejection of seamless steel gas cylinders at time of final inspection by the
manufacturer.26
Annex B (normative) Ultrasonic examination.32
Annex C (informative) Type approval certificate .38
Annex D (informative) Acceptance certificate.39
Bibliography.41

ISO 9809-1:2010(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 9809-1 was prepared by Technical Committee ISO/TC 58, Gas cylinders, Subcommittee SC 3, Cylinder
design.
This second edition cancels and replaces the first edition (ISO 9809-1:1999), which has been technically
revised by the following:
a) the reduction of maximum sulfur content in 6.2.2 from 0,020 % to 0,010 %, which is now applicable to all
strength levels;
b) the note in 7.3 regarding limitation of the F factor was deleted (as required by the United Nations
Recommendations on the Transport of Dangerous Goods: Model Regulations);
c) the modification of provisions for ultrasonic examination in 8.4 to include ultrasonic examination on the
cylindrical area to be closed, prior to the forming process;
d) the addition of the requirement of a base check according to 9.2.3 for all cylinder types during prototype
testing;
e) the addition of the requirement of a base check according to 9.2.3 for cylinders made from continuously
cast billet material during batch testing.
ISO 9809 consists of the following parts, under the general title Gas cylinders — Refillable seamless steel gas
cylinders — Design, construction and testing:
⎯ Part 1: Quenched and tempered steel cylinders with tensile strength less than 1 100 MPa
⎯ Part 2: Quenched and tempered steel cylinders with tensile strength greater than or equal to 1 100 MPa
⎯ Part 3: Normalized steel cylinders
Stainless steel cylinders with tensile strength of less than 1 100 MPa will form the subject of a Part 4.

iv © ISO 2010 – All rights reserved

ISO 9809-1:2010(E)
Introduction
This part of ISO 9809 provides a specification for the design, manufacture, inspection and testing of a
seamless steel cylinder for worldwide usage. The objective is to balance design and economic efficiency
against international acceptance and universal utility.
ISO 9809 (all parts) aims to eliminate existing concerns about climate, duplicate inspections and restrictions
because of a lack of definitive International Standards. This part of ISO 9809 should not be construed as
reflecting on the suitability of the practice of any nation or region.
This part of ISO 9809 addresses the general requirements on design, construction and initial inspection and
testing of pressure receptacles of the United Nations Recommendations on the Transport of Dangerous
Goods: Model Regulations.
It is intended to be used under a variety of regulatory regimes, but is suitable for use with the conformity
assessment system in 6.2.2.5 of the above-mentioned Model Regulations.

INTERNATIONAL STANDARD ISO 9809-1:2010(E)

Gas cylinders — Refillable seamless steel gas cylinders —
Design, construction and testing —
Part 1:
Quenched and tempered steel cylinders with tensile strength
less than 1 100 MPa
1 Scope
This part of ISO 9809 specifies minimum requirements for the material, design, construction and workmanship,
manufacturing processes, examination and testing at manufacture of refillable quenched and tempered
seamless steel gas cylinders of water capacities from 0,5 l up to and including 150 l for compressed, liquefied
and dissolved gases. This part of ISO 9809 is applicable to cylinders with a maximum actual tensile strength
R of less than 1 100 MPa.
ma
NOTE 1 If desired, cylinders of water capacity less than 0,5 l and between 150 l and 500 l can be manufactured and
certified to be in compliance with this part of ISO 9809.
NOTE 2 For quenched and tempered steel cylinders with maximum tensile strength greater than or equal to 1 100 MPa,
see ISO 9809-2. For normalized steel cylinders, see ISO 9809-3.
2 Normative references
The following referenced documents are indispensable for the application 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.
ISO 148-1, Metallic materials — Charpy pendulum impact test — Part 1: Test method
ISO 6506-1, Metallic materials — Brinell hardness test — Part 1: Test method
ISO 6508-1, Metallic materials — Rockwell hardness test — Part 1: Test method (scales A, B, C, D, E, F, G, H,
K, N, T)
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO 7438, Metallic materials — Bend test
ISO 9329-1, Seamless steel tubes for pressure purposes — Technical delivery conditions — Part 1: Unalloyed
steels with specified room temperature properties
ISO 9712, Non-destructive testing — Qualification and certification of personnel
ISO 11114-1, Transportable gas cylinders — Compatibility of cylinder and valve materials with gas
contents — Part 1: Metallic materials
ISO 11114-4, Transportable gas cylinders — Compatibility of cylinder and valve materials with gas
contents — Part 4: Test methods for selecting metallic materials resistant to hydrogen embrittlement
ISO 13769, Gas cylinders — Stamp marking
ISO 9809-1:2010(E)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
batch
quantity of up to 200 cylinders plus cylinders for destructive testing of the same nominal diameter, thickness,
length and design made successively on the same equipment, from the same cast of steel and subjected to
the same heat treatment for the same duration of time
3.2
burst pressure
p
b
highest pressure reached in a cylinder during a burst test
3.3
design stress factor
F
ratio of equivalent wall stress at test pressure, p , to guaranteed minimum yield strength, R
h eg
3.4
quenching
hardening heat treatment in which a cylinder, which has been heated to a uniform temperature above the
upper critical point, Ac , of the steel, is cooled rapidly in a suitable medium
3.5
tempering
toughening heat treatment which follows quenching, in which the cylinder is heated to a uniform temperature
below the lower critical point, Ac , of the steel
3.6
test pressure
p
h
required pressure applied during a pressure test
NOTE It is used for cylinder wall thickness calculation.
3.7
working pressure
settled pressure of a compressed gas at a uniform reference temperature of 15 °C in a full gas cylinder
3.8
yield strength
stress value corresponding to the upper yield strength, R , or for steels which do not exhibit a defined yield,
eH
the 0,2 % proof strength (non-proportional extension), R
p0,2
See ISO 6892-1.
4 Symbols
a Calculated minimum thickness, in millimetres, of the cylindrical shell
a′ Guaranteed minimum thickness, in millimetres, of the cylindrical shell
a Guaranteed minimum thickness, in millimetres, of a concave base at the knuckle (see Figure 2)
2 © ISO 2010 – All rights reserved

ISO 9809-1:2010(E)
a Guaranteed minimum thickness, in millimetres, at the centre of a concave base (see Figure 2)
A Percentage elongation after fracture
b Guaranteed minimum thickness, in millimetres, at the centre of a convex base (see Figure 1)
c Maximum permissible deviation of burst profile, in millimetres (see Figures 10 and 11)
D Nominal outside diameter of the cylinder, in millimetres (see Figure 1)
D Diameter, in millimetres, of former (see Figure 6)
f
F Design stress factor (variable) (see 3.3)
h Outside depth (concave base end), in millimetres (see Figure 2)
H Outside height, in millimetres, of domed part (convex head or base end) (see Figure 1)
L Original gauge length, in millimetres, as defined in ISO 6892-1 (see Figure 5)
o
N Ratio of the diameter of the bend test former to actual thickness of test piece, t
1)
p Measured burst pressure, in bars , above atmospheric pressure
b
P Hydraulic test pressure, in bars, above atmospheric pressure
h
P Observed pressure when cylinder starts yielding during hydraulic burst test, in bars, above atmospheric
y
pressure
r Inside knuckle radius, in millimetres (see Figures 1 and 2)
R Minimum guaranteed value of the yield strength (see 7.1.1), in megapascals, for the finished cylinder
eg
R Actual value of the yield strength, in megapascals, as determined by the tensile test (see 10.2)
ea
R Minimum guaranteed value of the tensile strength, in megapascals, for the finished cylinder
mg
R Actual value of tensile strength, in megapascals, as determined by the tensile test (see 10.2)
ma
S Original cross-sectional area of tensile test piece, in square millimetres, in accordance with ISO 6892-1
o
t Actual thickness of the test specimen, in millimetres
t average cylinder wall thickness at position of testing during the flattening test, in millimetres
m
u Ratio of distance between knife edges or platens in the flattening test to average cylinder wall thickness
at the position of test
V Water capacity of cylinder, in litres
w Width, in millimetres, of the tensile test piece (see Figure 5)

5 Inspection and testing
NOTE Evaluation of conformity can be carried out according to the regulations recognized by the country(ies) in
which the cylinders are intended to be used.

5 5 2
1) 1 bar = 10 Pa = 10 N/m .
ISO 9809-1:2010(E)
To ensure that the cylinders conform to this part of ISO 9809, they shall be subject to inspection and testing in
accordance with Clauses 9, 10 and 11 by an inspection body (hereinafter referred to as "the inspector")
authorized to do so.
Equipment used for measurement, testing and examination during production shall be maintained and
calibrated within a documented quality management system.
6 Materials
6.1 General requirements
6.1.1 Materials for the manufacture of gas cylinders shall fall within one of the following categories:
a) internationally recognized cylinder steels;
b) nationally recognized cylinder steels;
c) new cylinder steels resulting from technical progress.
For all categories, the relevant conditions specified in 6.2 and 6.3 shall be satisfied.
6.1.2 The material used for the manufacture of gas cylinders shall be steel, other than rimming quality, with
non-ageing properties, and shall be fully killed with aluminium and/or silicon.
In cases where examination of this non-ageing property is required by the customer, the criteria by which it is
to be specified should be agreed with the customer and inserted in the order.
6.1.3 The cylinder manufacturer shall establish means to identify the cylinders with the cast of steel from
which they are made.
6.1.4 Grades of steel used for cylinder manufacture shall be compatible with the intended gas service, e.g.
corrosive gases and embrittling gases (see ISO 11114-1).
6.1.5 Wherever continuously cast billet material is used, the manufacturer shall ensure that there are no
deleterious imperfections (porosity) in the material to be used for making cylinders (see 9.2.3).
6.2 Controls on chemical composition
6.2.1 The chemical composition of all steels shall be defined at least by:
⎯ the carbon, manganese and silicon contents in all cases;
⎯ the chromium, nickel and molybdenum contents or other alloying elements intentionally added to the
steel;
⎯ the maximum sulfur and phosphorus contents in all cases.
The carbon, manganese and silicon contents and, where appropriate, the chromium, nickel and molybdenum
contents shall be given, with tolerances, such that the differences between the maximum and minimum values
of the cast do not exceed the values shown in Table 1.
The combined content of the following elements: vanadium, niobium, titanium, boron and zirconium shall not
exceed 0,15 %.
The actual content of any element deliberately added shall be reported and their maximum content shall be
representative of good steel making practice.
4 © ISO 2010 – All rights reserved

ISO 9809-1:2010(E)
Table 1 — Chemical composition tolerances
Element Maximum content Permissible range
(mass fraction) (mass fraction)
% %
Carbon < 0,30 % 0,06
W 0,30 % 0,07
Manganese All values 0,30
Silicon All values 0,30
Chromium < 1,50 % 0,30
W 1,50 % 0,50
Nickel All values 0,40
Molybdenum All values 0,15
6.2.2 Sulfur and phosphorus in the cast analysis of material used for the manufacture of gas cylinders shall
not exceed the values shown in Table 2.
Table 2 — Maximum sulfur and phosphorus limits in % (mass fraction)
Sulfur 0,010
Phosphorus 0,020
Sulfur and phosphorus 0,025
6.2.3 The cylinder manufacturer shall obtain and make available certificates of cast (heat) analyses of the
steels supplied for the construction of gas cylinders.
Should check analyses be required, they shall be carried out either on specimens taken during manufacture
from the material in the form as supplied by the steel maker to the cylinder manufacturer or from finished
cylinders. In any check analysis, the maximum permissible deviation from the limits specified for the cast
analyses shall conform to the values specified in ISO 9329-1.
6.3 Typical steels
Two typical internationally recognized steel types which have provided safe performance over many years
are:
a) chromium molybdenum steel (quenched and tempered);
b) carbon manganese steel (quenched and tempered).
The chemical compositions of these steels, subject to the controls specified in 6.2.1, are given in Table 3.
ISO 9809-1:2010(E)
Table 3 — Internationally recognized steel compositions (mass fraction)
Element Steel grade and conditions
CrMo (Q and T) CMn (Q and T)
% %
Carbon 0,25 to 0,38 0,38 max.
Silicon 0,10 to 0,40 0,1 to 0,35
Manganese 0,40 to 1,00 1,35 to 1,75
Phosphorus 0,020 max. 0,020 max.
Sulfur 0,020 max. 0,020 max.
Chromium 0,8 to 1,20
Molybdenum 0,15 to 0,40
The actual range for each element shall be in accordance with 6.2.1 and 6.2.2 and good steel making practice. In
particular, the limits specified in Table 2 take precedence over the ranges given in this table.

6.4 Heat treatment
6.4.1 The cylinder manufacturer shall certify the heat treatment process applied to the finished cylinders.
6.4.2 Quenching in media other than mineral oil is permissible provided that:
⎯ the method produces cylinders free of cracks.
⎯ the manufacturer ensures that the rate of cooling does not produce any cracks in the cylinder.
⎯ every production cylinder is subjected to a method of non-destructive testing to prove freedom from
cracks, if the average rate of cooling in the medium is greater than 80 % of that in water at 20 °C without
additives.
⎯ during the production of cylinders, the concentration of the quenchant is checked and recorded during
every shift to ensure that the limits are maintained. Further documented checks shall be carried out to
ensure that the chemical properties of the quenchant are not degraded.
6.4.3 The tempering process shall achieve the required mechanical properties.
The actual temperature to which a type of steel is subjected for a given tensile strength shall not deviate by
more than 30 °C from the temperature specified by the cylinder manufacturer.
6.5 Failure to meet test requirements
In the event of failure to meet the test requirements, retesting or reheat treatment and retesting shall be
carried out as follows to the satisfaction of the inspector.
a) If there is evidence of a fault in carrying out a test or an error of measurement, a further test shall be
performed. If the result of this test is satisfactory, the first test shall be ignored.
b) If the test has been carried out in a satisfactory manner, the cause of test failure shall be identified.
1) If the failure is considered to be due to the heat treatment applied, the manufacturer may subject all
the cylinders implicated by the failure to a further heat treatment, e.g. if the failure is in a test
representing the prototype or batch cylinders. Test failure shall require reheat treatment of all the
represented cylinders prior to retesting.
6 © ISO 2010 – All rights reserved

ISO 9809-1:2010(E)
This reheat treatment shall consist of either re-tempering or complete reheat treatment.
Whenever cylinders are reheat treated, the minimum guaranteed wall thickness shall be maintained.
Only the relevant prototype or batch tests needed to prove the acceptability of the new batch shall be
performed again. If one or more tests prove even partially unsatisfactory, all cylinders of the batch
shall be rejected.
2) If the failure is due to a cause other than the heat treatment applied, all cylinders with imperfections
shall be either rejected or repaired such that the repaired cylinders pass the test(s) required for the
repair. They shall then be re-instated as part of the original batch.
7 Design
7.1 General requirements
7.1.1 The calculation of the wall thickness of the pressure-containing parts shall be related to the
guaranteed minimum yield strength, R , of the material in the finished cylinder.
eg
7.1.2 Cylinders may be designed with one or two openings along the central cylinder axis only.
7.1.3 For calculation purposes, the value of R shall not exceed 0,90 R .
eg mg
7.1.4 The internal pressure upon which the calculation of wall thickness is based shall be the hydraulic test
pressure p .
h
7.2 Limitation on tensile strength
7.2.1 Where there is no risk of hydrogen embrittlement, the maximum value of the tensile strength is limited
by the ability of the steel to meet the requirements of Clauses 9 and 10, but the maximum actual tensile
strength, R , shall always be less than 1 100 MPa for chrome-molybdenum steels and in no case exceed
ma
1 030 MPa for carbon manganese steels.
7.2.2 Where there is a risk of hydrogen embrittlement (see ISO 11114-1), the maximum value of the tensile
strength, as determined in 10.2, shall either be 880 MPa or, where the ratio R /R does not exceed 0,9, be
ea ma
950 MPa. Alternatively, the maximum tensile strength shall be established using data derived from the tests
carried out in accordance with ISO 11114-4.
7.2.3 Other gas/material compatibility risks, including stress corrosion and hydrogen embrittlement
mechanism by gases other than hydrogen, shall be assessed in accordance with ISO 11114-1 and
ISO 11114-4.
7.3 Calculation of cylindrical shell thickness
The guaranteed minimum thickness of the cylindrical shell, a′, shall not be less than the thickness calculated
using Equations (1) and (2), and additionally, condition (3) shall be satisfied.
⎛⎞
10 FR − 3
P
D h
eg
⎜⎟
a= 1 − (1)
⎜⎟
210 FR
⎜⎟
eg
⎝⎠
0,65
where the value of F is the lesser of  or 0,85.
RR
eg mg
ISO 9809-1:2010(E)
R /R shall not exceed 0,90.
eg mg
The wall thickness shall also satisfy Equation (2):
D
aW + 1 (2)
with an absolute minimum of a = 1,5 mm.
The burst ratio shall be satisfied by test as given in Equation (3):
p /p W 1,6 (3)
b h
NOTE It is generally assumed that p = 1,5 times working pressure for compressed gases for cylinders designed and
h
manufactured to conform with this part of ISO 9809.
7.4 Calculation of convex ends (heads and bases)
7.4.1 The thickness, b, at the centre of a convex end shall be not less than that required by the following
criteria: where the inside knuckle radius, r, is not less than 0,075D then:
b W 1,5 a for 0,40 > H/D W 0,20;
b W a for H/D W 0,40.
To obtain a satisfactory stress distribution in the region where the end joins the shell, any thickening of the
end that may be required shall be gradual from the point of juncture, particularly at the base. For the
application of this rule, the point of juncture between the shell and the end is defined by the horizontal lines
indicating dimension H in Figure 1.
Shape b) shall not be excluded from this requirement.
7.4.2 The cylinder manufacturer shall prove by the pressure cycling test detailed in 9.2.2 that the design is
satisfactory.
The shapes shown in Figure 1 are typical of convex heads and base ends. Shapes a), b), d) and e) are base
ends and shapes c) and f) are heads.

8 © ISO 2010 – All rights reserved

ISO 9809-1:2010(E)
Key
1 cylindrical part
Figure 1 — Typical convex ends

ISO 9809-1:2010(E)
7.5 Calculation of concave base ends
When concave base ends (see Figure 2) are used, the following design values are recommended:
a W 2a
a W 2a
h W 0,12D
r W 0,075D
The design drawing shall at least show values for a , a , h and r.
1 2
To obtain a satisfactory stress distribution, the thickness of the cylinder shall increase progressively in the
transition region between the cylindrical part and the base.
The cylinder manufacturer shall in any case prove by the pressure cycling test detailed in 9.2.2 that the design
is satisfactory.
Figure 2 — Concave base end
7.6 Neck design
7.6.1 The external diameter and thickness of the formed neck end of the cylinder shall be adequate for the
torque applied in fitting the valve to the cylinder. The torque may vary according to the diameter of thread, the
form of thread and the sealant used in the fitting of the valve.
NOTE For information on torques, see ISO 13341.
7.6.2 In establishing the minimum thickness, consideration shall be given to obtaining a thickness of wall in
the cylinder neck which will prevent permanent expansion of the neck during the initial and subsequent fittings
of the valve into the cylinder without support of an attachment. The external diameter and thickness of the
formed neck end of the cylinder shall not be damaged (no permanent expansion or crack) by the application of
the maximum torque required to fit the valve to the cylinder (see ISO 13341) and the stresses when the
cylinder is subjected to its test pressure. In specific cases (e.g. very thin walled cylinders), where these
stresses cannot be supported by the neck itself, the neck may be designed to require reinforcement, such as
a neck ring or shrunk on collar, provided the reinforcement material and dimensions are clearly specified by
the manufacturer and this configuration is part of the type approval procedure.
10 © ISO 2010 – All rights reserved

ISO 9809-1:2010(E)
7.7 Foot rings
When a foot ring is provided, it shall be sufficiently strong and made of material compatible with that of the
cylinder. The shape should preferably be cylindrical and shall give the cylinder sufficient stability. The foot ring
shall be secured to the cylinder by a method other than welding, brazing or soldering. Any gaps which may
form water traps shall be sealed by a method other than welding, brazing or soldering.
7.8 Neck rings
When a neck ring is provided, it shall be sufficiently strong and made of material compatible with that of the
cylinder and shall be securely attached by a method other than welding, brazing or soldering.
The manufacturer shall ensure that the axial load to remove the neck-ring is greater than 10 times the weight
of the empty cylinder, but not less than 1 000 N and that the torque to turn the neck ring is greater than
100 Nm.
7.9 Design drawing
A fully dimensioned drawing shall be prepared, which includes the specification of the material and details
relevant to the design of the permanent fittings. Dimensions of non-safety related fittings can be agreed on
between the customer and manufacturer and need not be shown on the design drawing.
8 Construction and workmanship
8.1 General
The cylinder shall be produced by
a) forging or drop forging from a solid ingot or billet, or
b) manufacturing from seamless tube, or
c) pressing from a flat plate.
Metal shall not be added in the process of closure of the end. Manufacturing defects shall not be corrected by
the plugging of bases.
8.2 Wall thickness
During production, each cylinder or semi-finished shell shall be examined for thickness. The wall thickness at
any point shall be not less than the minimum thickness specified.
8.3 Surface imperfections
The internal and external surfaces of the finished cylinder shall be free from imperfections which could
adversely affect the safe working of the cylinder.
NOTE For examples of imperfections and assistance on their evaluation, see Annex A.
8.4 Ultrasonic examination
8.4.1 After completion of the final heat treatment and after the final cylindrical wall thickness has been
achieved, each cylinder shall be ultrasonically examined for internal, external and sub-surface imperfections in
accordance with Annex B.
ISO 9809-1:2010(E)
For small completed cylinders with a cylindrical length of less than 200 mm or where the product of p × V <
h
600 (for R W 650 MPa) or p × V < 1 200 (for R < 650 MPa), the ultrasonic examination is not necessary.
ma h ma
8.4.2 Regardless of the size of the cylinder, in addition to the ultrasonic examination as specified in 8.4.1,
the cylindrical area to be closed (which creates the shoulder and, in case of cylinders made from tube, also
the base) shall be ultrasonically examined prior to the forming process to detect any defects that after closure
could be positioned in the cylinder ends.
NOTE This examination does not necessarily cover the tests required in 6.4.2.
8.5 Out-of-roundness
The out-of-roundness of the cylindrical shell, i.e. the difference between the maximum and minimum outside
diameters at the same cross-section, shall not exceed 2 % of the mean of these diameters.
8.6 Mean diameter
The mean external diameter of the cylindrical part outside the transition zones on a cross-section shall not
deviate by more than ± 1 % from the nominal design diameter.
8.7 Straightness
The maximum deviation of the cylindrical part of the shell from a straight line shall not exceed 3 mm/m length
(see Figure 3).
8.8 Verticality and stability
For a cylinder designed to stand on its base, the deviation from vertical shall not exceed 10 mm/m length (see
Figure 3) and the outer diameter of the surface in contact with the ground is recommended to be greater than
75 % of the nominal outside diameter.
8.9 Neck threads
The internal neck threads shall conform to a recognized standard agreed between the parties to permit the
use of a corresponding valve thus minimizing neck stresses following the valve torquing operation. Internal
neck threads shall be checked using gauges corresponding to the agreed neck thread or by an alternative
method agreed on between the parties.
NOTE For example, where the neck thread is specified to be in accordance with ISO 11116-1, the corresponding
gauges are specified in ISO 11116-2.
Particular care shall be taken to ensure that neck threads are accurately cut, are of full form and free from any
sharp profiles, e.g. burrs.
12 © ISO 2010 – All rights reserved

ISO 9809-1:2010(E)
Key
a
maximum 0,01 × l (see 8.8)
b
maximum 0,003 × l (see 8.7)
Figure 3 — Illustration of deviation of cylindrical part of shell from a straight line and from vertical
9 Type approval procedure
9.1 General requirements
A technical specification of each new design of cylinder or cylinder family as defined in f), including design
drawing, design calculations, steel details, manufacturing process and heat treatment details, shall be
submitted by the manufacturer to the inspector. The type approval tests detailed in 9.2 shall be carried out on
each new design under the supervision of the inspector.
A cylinder shall be considered to be of a new design, compared with an existing approved design, when at
least one of the following applies:
a) it is manufactured in a different factory;
b) it is manufactured by a different process (see 8.1); this includes the case when major process changes
are made during the production period, e.g. end forging to spinning and change in the heat treatment
process;
c) it is manufactured from a steel of different specified chemical composition range from that defined in
6.
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