EN 1968:2002

SLOVENSKI STANDARD
01-november-2002
3UHPLþQHSOLQVNHMHNOHQNH3HULRGLþQLQDG]RULQSUHVNXVMHNOHQLKMHNOHQNL]FHOHJD
Transportable gas cylinders - Periodic inspection and testing of seamless steel gas
cylinders
Ortsbewegliche Gasflaschen - Wiederkehrende Prüfung von nahtlosen Gasflaschen aus
Stahl
Bouteilles a gaz transportables - Contrôles et essais périodiques des bouteilles a gaz
sans soudure en acier
Ta slovenski standard je istoveten z: EN 1968:2002
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 1968
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2002
ICS 23.020.30
English version
Transportable gas cylinders - Periodic inspection and testing of
seamless steel gas cylinders
Bouteilles à gaz transportables - Contrôles et essais Ortsbewegliche Gasflaschen - Wiederkehrende Prüfung
périodiques des bouteilles à gaz sans soudure en acier von nahtlosen Gasflaschen aus Stahl
This European Standard was approved by CEN on 9 November 2001.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2002 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 1968:2002 E
worldwide for CEN national Members.

Contents
page
Foreword.3
Introduction .4
1 Scope .5
2 Normative references .5
3 Intervals between periodic inspection and test.6
4 List of procedures for periodic inspection and test.6
5 Identification of cylinder and preparation for inspection and test .7
6 External visual inspection.7
7 Internal visual inspection.8
8 Supplementary tests.8
9 Inspection of cylinder neck.8
10 Pressure test or ultrasonic test.9
11 Inspection of valve.10
12 Final operations .10
13 Rejection and rendering cylinder unserviceable.12
Annex A (informative)  Gas cylinders manufactured according to National Regulations.13
Annex B (normative)  Inspection periods .15
Annex C (normative)  Description, evaluation of defects and conditions for rejection of seamless steel
gas cylinders at time of visual inspection.16
Annex D (normative)  Procedure to be adopted when a cylinder valve is suspected to be obstructed .20
Annex E (normative)  Proof pressure test of gas cylinders.23
Annex F (normative)  Volumetric expansion testing of gas cylinders.24
Annex G (normative)  Ultrasonic test.33
Annex H (informative)  Inspection and maintenance of valves and their connections: recommended
procedures.45
Annex I (informative)  List of commonly used gases corrosive to cylinder material.46
Bibliography .47
Foreword
This document EN 1968:2002 has been prepared by 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 August 2002, and conflicting national standards shall be withdrawn at the latest by
August 2002.
In this standard the annexes B, C, D, E, F and G are normative and the annexes A, H and I are informative.
This document has been prepared under a mandate given to CEN by the European Commission and the European
Free Trade Association, and supports the objectives of the framework Directives on Transport of Dangerous
Goods.
This European Standard has been submitted for reference into the RID and/or the technical annexes of the ADR.
Therefore in this context the standards listed in the normative references and covering basic requirements of the
RID/ADR not addressed within the present standard are normative only when the standards themselves are
referred to in the RID and/or the technical annexes of the ADR.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,
France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain,
Sweden, Switzerland and the United Kingdom.
Introduction
The principal aim of a periodic inspection and testing procedure is that at the completion of the test the cylinders
may be reintroduced into service for a further period of time.
Experience of the inspection and testing of cylinders which is specified in this European Standard is an important
factor when determining whether a cylinder should be returned into service.
1 Scope
This European Standard specifies the requirements for periodic inspection and testing of seamless steel
transportable gas cylinders (single or those from bundles) intended for compressed and liquefied gases under
pressure, of water capacity from 0,5 l up to 150 l.
NOTE  As far as practicable, this standard may also be applied to cylinders of less than 0,5 l water capacity.
This standard specifies the requirements for periodic inspection and testing to verify the integrity of such gas cylinders
to be reintroduced into service for a further period of time. It also defines a procedure to qualify existing gas cylinders
for free movement between member states of the European Union (see annex A).
This standard does not apply to periodic inspection and testing of acetylene cylinders or composite (fully wrapped or
hoop-wrapped) steel cylinders.
2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate place in the text, and the publications are listed hereafter. For dated
references, subsequent amendments to or revisions of any of these publications apply to this European Standard only
when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred
to applies (including amendments).
EN 473, Non destructive testing - Qualification and certification of NDT personnel - General principles.
EN 629-2, Transportable gas cylinders — 25E taper thread for connection of valves to gas cylinders — Part 2: Gauge
inspection.
EN 837-1, Pressure gauges — Part 1: Bourdon tube pressure gauges — Dimensions, metrology, requirements and
testing.
EN 837-3, Pressure gauges — Part 3: Diaphragm and capsule pressure gauges — Dimension, metrology,
requirements and testing.
EN 1089-1, Transportable gas cylinders — Gas cylinder identification (excluding LPG) — Part 1: Stampmarking.
EN 1964-1, Transportable gas cylinders — Specification for the design and construction of refillable transportable
seamless steel gas cylinders of water capacities from 0,5 litre up to and including 150 litres — Part 1: Cylinders made
of seamless steel with an R value of less than 1100 MPa.
m
prEN 1964-2, Transportable gas cylinders — Specification for the design and construction of refillable transportable
seamless steel gas cylinders of water capacities from 0,5 litre up to and including 150 litres — Part 2: Cylinders made
of seamless steel with an R value of 1100 MPa and above.
m
EN 1964-3, Transportable gas cylinders — Specification for the design and construction of refillable transportable
seamless steel gas cylinders of water capacities from 0,5 litre up to and including 150 litres — Part 3: Cylinders made
of seamless stainless steel with an R value of less than 1100 MPa.
m
EN 1795, Transportable gas cylinders (excluding LPG) — Procedures for change of gas service.
EN ISO 11114-1, Transportable gas cylinders — Compatibility of cylinder and valve materials with gas contents —
Part 1: Metallic materials (ISO 11114-1:1997).
EN ISO 11114-2, Transportable gas cylinders — Compatibility of cylinder and valve materials with gas contents —
Part 2: Non-metallic materials (ISO 11114-2:2000).
EN ISO 13341, Transportable gas cylinders — Fitting of valves to gas cylinders (ISO 13341:1997).
3 Intervals between periodic inspection and test
In order to ensure continued safe operation, cylinders shall be periodically submitted to inspection and test in
accordance with annex B. A cylinder shall fall due for a periodic inspection and test on its first receipt by a filler after
the expiry of the interval in annex B.
NOTE Table B.1 gives a list of the intervals between periodic inspections for some gases which complies with the current
RID/ADR regulations and also gives recommendations which could be subsequently adopted by the RID/ADR regulations.
Provided the cylinder has been subjected to normal conditions of use and has not been subjected to abusive and
abnormal conditions rendering the cylinder unsafe, there is no general requirement for the user to return a gas
cylinder before the contents have been used even though the test interval may have lapsed. However it is
recommended that cylinders are retested within a period not exceeding twice the time interval.
In the case of cylinders used for emergency purposes (e.g. fire extinguishers, breathing apparatus), it is the
responsibility of the person in possession (owner or user) to submit it for a periodic inspection within the interval
specified in annex B or as specified in the relevant cylinder design standard/regulation, if this is shorter.
4 List of procedures for periodic inspection and test
The inspection and test shall be carried out only by competent persons who shall ensure that the cylinders are fit
for continued safe use.
NOTE A competent person is a person who has the necessary technical knowledge, experience and authority to assess
and approve materials for use with gases and to define any special conditions of use that are necessary. Such a person will also
normally be formally qualified in an appropriate technical discipline.
Each cylinder shall be submitted to periodic inspection and test. The following procedures form the requirements
for such inspection and test, and are explained more fully in later clauses:
- identification of cylinder and preparation for inspection and test (clause 5);
- external visual inspection (clause 6);
- internal visual inspection (clause 7);
- supplementary tests (clause 8);
- inspection of cylinder neck (clause 9);
- pressure test or ultrasonic test (clause 10);
- inspection of valve (clause 11);
- final operations (clause 12);
- rejection and rendering cylinders unserviceable (clause 13).
Where cylinders are manufactured according to National Regulations and are intended to be qualified under the
Transportable Pressure Equipment Directive (TPED) for free movement and use between member states of the
European Union, additional requirements are specified in annex A.
It is recommended that the above listed tests are performed in the suggested sequence. In particular the internal
visual examination (clause 7) should be carried out before the pressure test or ultrasonic test (clause 10).
Cylinders which fail the inspection or tests shall be rejected (see clause 13). When, after the above tests, doubts
still exist as to the extent of a defect or the condition of a cylinder, then additional tests may be performed in
accordance with clause 8, until such doubts are positively resolved or the cylinder shall be rendered unserviceable.
Some cylinders rejected during periodic inspection and test may be recovered in accordance with annex C.
5 Identification of cylinder and preparation for inspection and test
Before any work is carried out, the relevant cylinder data (e.g. see EN 1089-1) and its contents and ownership shall
be identified.
If contents are identified as hydrogen or other embrittling gases only those cylinders manufactured or qualified as a
hydrogen cylinder shall be used for that service. Such cylinders shall be checked that they are compatible with
hydrogen service i.e. with respect to the maximum tensile strength and internal surface condition (e.g. cylinders
stamp marked according to EN 1089-1 are stamped "H"). All other cylinders shall be withdrawn from hydrogen
service and their suitability checked for their new intended service.
The cylinders shall be depressurized and emptied in a safe, controlled manner before proceeding. Particular
attention shall be given to cylinders containing flammable, oxidizing and toxic gases to eliminate risks at the internal
inspection stage.
Cylinders with incorrect markings, unknown gas contents, or those which cannot be safely emptied of gas, shall be
set aside for special handling.
Cylinders with inoperative or blocked valves may be treated as outlined in annex D. Provided the requirements
above have been complied with, and the cylinder has been depressurized safely, the valve shall be removed.
Similarly in the case of cylinder bundles, not equipped with cylinder valves, the connecting tee junction shall also be
checked to determine whether the gas is able to pass freely from the cylinder to atmosphere.
6 External visual inspection
6.1 Preparation for external visual inspection
Each cylinder shall be cleaned and have all loose coatings, corrosion products, tar, oil or other foreign matter
removed from its external surface by a suitable method, e.g. by brushing, shot blasting (under closely controlled
conditions), water jet abrasive cleaning, chemical cleaning or other suitable methods. Care shall be taken at all
times to avoid damaging the cylinder, or removing excess amounts of cylinder wall.
If fused nylon, polyethylene or a similar coating has been applied and is seen to be damaged, or prevents a proper
inspection, then the coating shall be removed. If the coating is removed by the application of heat, the temperature
of the cylinder shall not exceed 300 °C.
6.2 Inspection procedure
The external surface of each cylinder shall then be inspected for:
a) dents, cuts, gouges, bulges, cracks, laminations or excessive base wear.
b) heat damage, torch or electric arc burns (as defined in Table C.1).
c) corrosion (as defined in Table C.2).
d) other defects such as illegible or unauthorized stamp markings, unauthorized additions or modifications.
e) integrity of all permanent attachments.
f) vertical stability (if relevant)(as defined in Table C.1).
For rejection criteria, see annex C. Cylinders no longer suitable for future service shall be rendered unserviceable
(as defined in clause 13).
7 Internal visual inspection
Each cylinder shall be inspected internally, using adequate illumination to identify any defects such as those listed
in 6.2 a) and 6.2 c). Precautions shall be taken to ensure that the method of illumination presents no hazards to the
tester whilst performing the operation. Any internal liner or coating which can obstruct optimum internal visual
inspection, shall be removed. Any cylinder showing presence of foreign matter or signs of more than light surface
corrosion shall be cleaned internally under closely controlled conditions by shot blasting, water jet abrasive
cleaning, flailing, steam jet, hot water jet, rumbling, chemical cleaning, or other suitable method. Care shall be
taken to avoid damage to the cylinder. If cleaning is required, the cylinder shall be re-inspected after the cleaning
operation.
For cylinders in non-corrosive gas service and less than 0,5 l water capacity with an internal neck diameter less
than 9 mm, alternative methods can be substituted for the internal visual inspection.
These alternative methods are :
a) look for any free moisture at the time of degassing the cylinder whilst in an inverted position and prior to valve
removal. If any moisture is present, the cylinder shall be rendered unserviceable;
and
b) look for contamination e.g. rust in the water used after the hydraulic test. If any contamination is found, the
cylinder shall be rendered unserviceable.
8 Supplementary tests
Where there is doubt concerning the type and/or severity of a defect found on visual inspection (see clauses 6
and 7), additional tests or methods of examination may be applied, e.g. ultrasonic techniques, check weighing or
other non-destructive tests. Only when all doubts are eliminated may the cylinder be further processed (see
annex C).
9 Inspection of cylinder neck
9.1 Internal neck thread
The internal neck thread of the cylinder shall be examined to ensure that it is:
- clean and of full form;
- free of damage;
- free of burrs;
- free of cracks;
- free of other imperfections.
Cracks manifest themselves as lines which run vertically down the thread and across the thread faces. They should
not be confused with tap marks (thread machining marks). Special attention should be paid to the area at the
bottom of the thread.
9.2 Other neck surfaces
Other surfaces of the neck shall also be examined to ensure they are free of cracks or other defects (see annex C).
9.3 Damaged internal neck threads
Where necessary, and where the manufacturer or the competent person confirms that the design of the neck
permits, threads may be re-tapped to provide the appropriate number of effective threads. After re-tapping, the
threads shall be checked by the appropriate thread gauge, (e.g. for 25E threads, in accordance with EN 629-2).
9.4 Neck ring and collar attachment
When a neck ring/collar is attached, an examination to ensure that it is secure and free from thread damage shall
be carried out. Neck rings shall only be changed using an approved procedure. If it is found that any significant
damage to cylinder material has occurred by replacement of the neck ring/collar, the cylinder shall be rendered
unserviceable. If the neck ring has been re-attached by welding or brazing, the cylinder shall be rendered
unserviceable.
10 Pressure test or ultrasonic test
10.1 General
Each cylinder shall be subjected to a pressure test (see 10.2) or to an ultrasonic test (see 10.3).
10.2 Pressure test
10.2.1 General requirements
When carrying out a pressure test, a suitable fluid, normally water shall be used as the test medium. The test may
be a proof pressure test (see 10.2.2) or a volumetric expansion test (see 10.2.3), as appropriate to the design of
the cylinder. Having decided to use one particular type of test, its result shall be final. No attempt shall be made to
transfer from one type of test to the other. The test pressure shall be in accordance with the stamping on the
cylinder.
The pressure in the cylinder shall be increased gradually until the test pressure is reached. The cylinder test
pressure shall be held for at least 30 s with the cylinder isolated from the pressure source, during which time there
shall be no decrease in the recorded pressure or any evidence of any leakage. Safety precautions shall be taken
during the test.
10.2.2 Proof pressure test
Annex E specifies a typical method for carrying out the test.
NOTE  A pneumatic pressure test can be substituted, provided approval from the relevant authority has been obtained.
Measures should be taken to ensure safe operation and to contain any energy, which is considerably more than that in the
hydraulic test, which can be released.
During the 30 s hold period the pressure as registered on the test gauge shall remain constant.
There shall be no visible leakage or visible permanent deformation on the entire surface of the cylinder. This check
may be made either during the 30 s hold or immediately after the pressure has been released.
Any cylinder failing to comply with the requirements of this test shall be rendered unserviceable.
10.2.3 Volumetric expansion test
Annex F specifies a typical method for carrying out the test and gives details for determining the volumetric
expansion of seamless steel gas cylinders by the preferred water jacket method or the non-water jacket method.
The permanent volumetric expansion of the cylinder expressed as a percentage of the total expansion at test
pressure shall not exceed the percentage given in the design specification after the cylinder has been held at test
pressure for a minimum period of 30 s. If this figure for permanent expansion is exceeded the cylinder shall be
rendered unserviceable.
10.3 Ultrasonic test
Ultrasonic testing may be used in place of the pressure test in the procedures of periodic inspection, with the
agreement of the competent person. Ultrasonic testing, if carried out, shall be in accordance with the method
specified in annex G.
11 Inspection of valve
If it is to be re-introduced into service, each valve (or tee junction for bundles) shall be inspected to verify that it will
perform satisfactorily and ensure gas tightness. An example of a suitable method is given in annex H.
12 Final operations
12.1 Drying, cleaning and painting
12.1.1 Drying and cleaning
The interior of each cylinder shall be thoroughly dried by a suitable method at a temperature not exceeding 300 °C,
immediately after hydraulic pressure testing, such that there is no trace of free water. The interior of the cylinder
shall be inspected to ensure that it is dry and free from other contaminants.
12.1.2 Painting
Cylinders are sometimes re-painted, using paints which require stoving. Plastics coatings may also be reapplied.
Painting or coating shall be applied such that all markings stamped on the cylinder are legible.
In no case shall the temperature of the cylinder exceed 300 °C.
12.2 Re-valving of the cylinder
The valve shall be fitted to the cylinder using a suitable sealing material. An optimum torque necessary to ensure
both a seal between the valve and the cylinder and prevent over-stressing the neck shall be used in accordance
with EN ISO 13341.
The torque applied shall take into consideration the size and form of the threads, the material of the valve, and the
type of sealing material used according to the manufacturer's recommendations. Where the use of
lubricants/sealing material is permitted, only those approved for the gas service shall be used, taking particular care
for oxygen service in accordance with EN ISO 11114-2.
12.3 Check on cylinder tare
This requirement applies only to cylinders for liquefied gases. The tare of the cylinders shall be obtained by
weighing on a machine regularly checked for accuracy. The capacity of the weighing machine shall be suitable for
the tare weight of the cylinders.
The tare shall include the mass of the cylinder, valve(s) and all permanent fittings. If the tare of the cylinder differs
from the stamped tare by more than the value shown in Table 1 and is not due to reasons of damage, the original
tare shall be cancelled and the correct tare shall be marked in a permanent and legible fashion in accordance with
EN 1089-1.
Table 1 — Maximum allowable deviation in
cylinder tare weight
Cylinder water Maximum allowable
capacity (V) deviation in tare
weight
lg
± 50
0,5
V  5,0
± 200
5,0
V
20
> 20 ± 400
12.4 Stampmarking
After satisfactory completion of the periodic inspection and test, each cylinder shall be permanently marked
according to EN 1089-1 with the present test date followed by the symbol of the inspection body or test station.
12.5 Reference to next test date
The next test date shall be shown in a clearly visible manner by an appropriate method such as a label or a disc
fitted between the valve and the cylinder, indicating the year of the next periodic inspection or periodic inspection
and test.
12.6 Identification of contents
Before the cylinder is reintroduced into service, the cylinder shall be marked according to the intended contents
(see e.g. EN 1089-2 and EN 1089-3). If painting is required, care shall be exercised in accordance with 12.1.2. If a
change of gas service is involved the requirements of EN 1795 shall be followed.
12.7 Records
Details of the present test shall be recorded by the test station and the following information shall be available:
- owner's name;
- manufacturer's or owner's serial number;
- cylinder tare, where applicable;
- test pressure;
- result of test (pass or fail);
- present test date;
- identification symbol of the inspection body or the test station;
- identification of inspector;
- details of any modifications made to the cylinder by the inspector.
Additionally, it shall be possible to obtain the following items of information from records, which need not
necessarily be kept on a single file, but will enable a particular cylinder to be traced. These items are:
- cylinder manufacturer;
- manufacturer's serial number;
- manufacturing specification;
- water capacity/size;
- manufacturing test date.
13 Rejection and rendering cylinder unserviceable
The decision to reject a cylinder may be taken at any stage during the inspection and test procedure. If it is not
possible to recover a rejected cylinder, it shall, after notifying the owner, be made unserviceable by the testing
station for holding gas under pressure so that it is impossible for any part of the cylinder, especially the shoulder, to
be re-issued into service.
In case of any disagreement, ensure that the legal implication of the contemplated action is fully understood.
One or a combination of the following methods can be employed to render the cylinder unserviceable, after
ensuring that the cylinder is empty and free of gas (see clause 5):
- crush the cylinder, preferably in the shoulder area, using mechanical means;
- burn an irregular hole in the top dome equivalent in area to approximately 10 % of the area of the top dome
or, in the case of a thin-walled cylinder pierce in at least three places;
- cut the neck in an irregular fashion;
- cut the cylinder including the shoulder into two or more irregular pieces;
- burst in a safe manner.
Annex A
(informative)
Gas cylinders manufactured according to National Regulations
A.1 Scope
This annex specifies those checks, inspections and tests which shall be performed in order to qualify existing gas
cylinders, manufactured according to National Regulations, to ensure their compliance with the TPED for free
movement and use between all Member States of the European Union.
The annex does not apply to and hence is not necessary for gas cylinders manufactured according to
EN 1964-1, prEN 1964-2 or EN 1964-3 (see also Directive 84/525/EEC).
A.2 Definition and symbol


official stamp mark required by the TPED to certify existing gas cylinders conforming to RID/ADR for use
throughout the European Union
A.3 General requirements
A.3.1 The owner of the gas cylinders shall indicate to the inspection body the types and the number of gas
cylinders presented for qualification.
For each of the cylinders the following information shall be made available for documentation and subsequent
calculation:
- manufacturer;
- serial number;
- date of manufacture;
- regulation or specification to which the cylinder was manufactured;
- working pressure;
- test pressure;
- external diameter;
- minimum wall thickness;
- minimum yield stress;
- water capacity.
The inspection body shall verify that this list contains all the necessary information to clearly define the cylinder
(see example of production testing certificate in the relevant annex of the relevant Part of EN 1964, for the above
listed parameters only).
A.3.2 The inspection body shall verify that these cylinders are not on any relevant national safety related recall
list. Additionally if any restrictions of use apply they shall be maintained for further use.
A.3.3 The owner shall provide information to enable the inspection body to verify that these cylinders are not or
have not been in carbon monoxide or carbon monoxide mixture service.
A.3.4 The inspection body shall verify that the wall thickness of the gas cylinders is equal to, or greater than, the
minimum wall thickness, as calculated in accordance with the relevant Part of EN 1964, for the corresponding yield
stress of the cylinder.
A.3.5 The inspection body shall verify that cylinders intended for use in hydrogen (or other embrittling gas
service) conform to EN ISO 11114-1.
A.3.6 The inspection body shall verify that the manufacturing certificates or equivalent records are available.
When manufacturing certificates are not available, the inspection body shall verify that all relevant type testing and
manufacturing batch testing have been performed.
A.3.7 The inspection body shall perform the periodic inspection according to this standard.
A.4 Specific requirements
If any of the general requirements in A.3.1 to A.3.6 are not fully met, the cylinder may be qualified if the inspection
body is able to verify the following, as appropriate:
a) The inspection body shall verify the calculation of the minimum wall and base thicknesses.
All the cylinders shall be ultrasonically tested according to the method indicated in annex G as appropriate to
verify that the minimum wall and base thicknesses of each cylinder are equal to or greater than the minimum
wall and base thickness prescribed by the relevant Part of EN 1964 and that the cylinders are free from harmful
defects, as described in annex C.
b) A hardness test shall be performed on each cylinder as described in EN 1964-1. The results shall be compared
to the requirements in the original specification, if available. Any significant deviation shall be indicated and
explained.
Where the hardness value is not specified a correlated hardness value shall be derived by the method as
described in prEN 1964-2.
c) For steel cylinders intended for use in hydrogen or other embrittling gas service, in addition to A.3.5, pressure
cycle tests as described in EN 1964-1 shall be repeated for each type of cylinder submitted. The acceptance
criteria shall correspond to those described in EN 1964-1.
d) The cylinder shall be hydraulically tested in accordance with 10.1 or 10.2 if not already hydraulically tested as
in A.3.7.
A.5 Special markings
A gas cylinder passing the periodic inspection may only be stamped with the mark “
“ provided that the
requirements under A.3 and A.4 as appropriate have been fully verified.
A.6 Inspection report
The inspection body shall prepare a report for each type of cylinder.
All relevant certifications, new tests and inspections performed shall be attached to this report.
Annex B
(normative)
Inspection periods
a
Table B.1 — Intervals between periodic inspections and test
c
Description Gas type (examples) Normative intervals Informative recommendations for next
b
Period revision of ADR
years Period
years
Compressed Ar, N , He etc. 10 10
gases d
H 10 10
Air, O 10 10
e
Self-contained 5
breathing Air, O , etc
e
Gases for underwater 2,5 (internal visual)
f
breathing apparatus and 5 (full)
g
CO 55
h
Liquefied CO , N O etc. 10 10
2 2
gases
i
Corrosive 3 3 (internal visual)
k
gases and 5 (full)
Toxic gases CH Br 5 10
Very toxic AsH , PH etc. 5 5
3 3
gases
Gas mixtures a) all mixtures except 3, 5 or 10 years according a) Lowest test period of any component
b) below to classification
b) mixtures 3 years for groups TC, b) For such mixtures, if the toxicity of the
completely in the TFC, TOC final mixture is such that LC
a volume
-6
gaseous state fraction of 200 × 10 , a 10 year period
5 years for groups T, TF,
containing toxic applies, and if the toxicity of the final
TO
and/or very toxic mixture is such that LC  a volume
–6
10 years for groups A, O, F
components. fraction of 200 × 10 a 5 year period
applies
a
At all times certain requirements may necessitate a shorter time interval e.g. the dew point of the gas, polymerization
reactions and decomposition reactions, cylinder design specification, change of gas service.
b
This list of gases is not exhaustive. A full list of gases can be found in RID/ADR.
c
These intervals conform to the 1999 edition of RID/ADR.
d
Pay particular attention to the requirements of clause 5 and possible additional testing in accordance with EN 1795 for
change of service.
e
Not currently listed in RID/ADR.
f
For cylinders used for self-contained underwater breathing apparatus in addition to the full retest period of 5 years, an
internal visual inspection need to be performed every 2,5 years.
g
This product requires very dry gas (see EN ISO 11114-1).
h
This test period may be used provided the dryness of the product and that of the filled cylinder are such that there is no free
water, and that this condition is proven and documented within a quality system of the filler. If these conditions cannot be
fulfilled alternative or more frequent testing may be appropriate.
i
For RID/ADR purposes, corrosivity is with reference to human tissue and NOT cylinder material, as per annex I.
k
For gas mixtures shown to be corrosive for the cylinder material, the time period for single corrosive gases applies.
Annex C
(normative)
Description, evaluation of defects and conditions for rejection of seamless
steel gas cylinders at time of visual inspection
C.1 General
Gas cylinder defects can be physical or material or due to corrosion as a result of environmental or service
conditions to which the cylinder has been subjected during its life.
The object of this annex is to give general guidelines to the gas cylinder users as to the application of rejection
criteria.
This annex applies to all cylinders but those which have contained gases having special characteristics can require
modified controls.
Any defect in the form of a sharp notch may be removed by grinding, machining or other approved methods.
After such a repair, checking of the wall thickness, e.g. ultrasonically, shall be repeated.
C.2 Physical or material defects
Evaluation of physical or material defects shall be in accordance with Table C.1.
C.3 Corrosion
C.3.1 General
The cylinder can be subjected to environmental conditions that could cause external corrosion of the metal.
Internal corrosion of the metal can also occur owing to service conditions.
There is difficulty in presenting definite rejection limits in tabular form for all sizes and types of cylinders and their
service conditions. The limits of rejection have been established following considerable field experience.
Extensive experience and judgment are required in evaluating whether cylinders that have corroded internally are
safe and suitable for return to service. It is important that the surface of the metal is cleaned of corrosion products
prior to the inspection of the cylinder.
C.3.2 Types of corrosion
The types of corrosion possible are classified as described in in Table C.2.
Table C.1 — Rejection limits relating to physical and material defects in the cylinder shell
Type of Definition Rejection limits in accordance Repair or render
a
defect with clause 6 unserviceable
Bulge Visible swelling of the cylinder All cylinders with such a defect Render
unserviceable
Dent A depression in the cylinder When the depth of the dent Render
that has neither penetrated nor exceeds 3 % of the external unserviceable
removed metal and is greater in diameter of the cylinder; or
depth than 1 % of the outside
When the diameter of the dent is Render
diameter
less than 15 times its depth unserviceable
b
Cut or gouge A sharp impression where When the depth of the cut or gouge Repair if possible
(see metal has been removed or exceeds 10 % of the wall thickness;
Figure C.1) redistributed and whose depth or
b
exceeds 5 % of the cylinder
When the length exceeds 25 % of Repair if possible
wall thickness
the outside diameter of the cylinder;
or
When the wall thickness is less Render
than the minimum design thickness unserviceable
Crack (see A rift or split in the metal All cylinders with such defects Render
Figure C.2) unserviceable
Fire damage Excessive general or localized
(see Figure heating of a cylinder usually All cylinders in categories a) and b) Render
C.3) indicated by: unserviceable
a) partial melting of the cylinder;
b) distortion of cylinder;
c) charring or burning of paint; All cylinders in categories c) and d) Repair if possible
may be acceptable after inspection
d) fire damage to valve, melting
and/or testing
of plastic guard or date ring.
Plug or neck Additional inserts fitted in the All cylinders unless it can be clearly Repair if possible
inserts cylinder neck, base or wall established that addition is part of
approved design
Stampmar- Marking by means of a metal All cylinders with illegible, modified Render
c
king punch or incorrect or incorrectly modified unserviceable
markings
Arc or torch Partial melting of the cylinder, All cylinders with such defects Render
burns (see the addition of weld metal or the unserviceable
Figure C.4) removal of metal by scarfing or
cratering
Suspicious Introduced other than by the All cylinders with such defects Continued use
marks cylinder manufacturing process possible after
or approved repair additional inspection
Vertical Deviation from verticality which can Repair if possible or
stability present a risk during service render unserviceable
(especially if fitted with foot-ring)
a
When applying the rejection criteria given in this table, the conditions of use of the cylinders, the severity of the defect and
safety factors in the design shall be taken into consideration.
b
Provided that after repair by a suitable metal removal technique, the remaining wall thickness is at least equal to the
design minimum wall thickness.
c
If it can be clearly established that the cylinder fully complies with the appropriate specifications, altered operational and
modified marking may be acceptable and inadequate markings may be corrected, provided there is no possibility of
confusion.
Table C.2 — Rejection criteria for corrosion of the cylinder wall
Type of Definition Rejection limits in Repair or render
a
corrosion accordance with clause 6 unserviceable
General Loss of wall thickness over If the original surface of the Repair if possible
corrosion an area of more than 20 % metal is no longer recognizable;
of the total surface area of or
(Figure C.5)
the cylinder
If the depth of penetration Repair if possible
exceeds 10 % of original (repeat requirements
b
thickness of wall ; or of clauses 6, 7 and 8)
If the wall thickness is less than Render
design minimum wall thickness. unserviceable
Local Loss of wall thickness over If the depth of penetration Repair if possible
corrosion an area of less than 20 % exceeds 20 % of the original (repeat requirements
b
of the total surface area of thickness of the cylinder wall ; of clauses 6, 7 and 8)
the cylinder except for the or if the wall thickness is less
other types of local than design thickness
corrosion described below
c
Chain pitting Corrosion forming a If the total length of corrosion in Repair if possible
or narrow longitudinal or any direction exceeds the
line corrosion circumferential line or strip, diameter of the cylinder and the
or isolated craters or pits depth exceeds 10 % of the
(Figure C.6)
b
(Figure C.7) which are original wall thickness
almost connected
a
If the bottom of the defect cannot be seen and if its extent cannot be determined using appropriate equipment,
the cylinder shall be rendered unserviceable.
b
If corrosion has reached limits of depth or extent, the remaining wall thickness should be checked with an
ultrasonic device. The wall thickness may be less than the minimum, with the acceptance of the inspection body,
e.g. small (depth and extent) isolated pits. When applying the rejection criteria given in this table, the conditions of
use of the cylinders, the severity of the defect and safety factors in the design shall be taken into consideration.
c
Provided that after repair by a suitable metal removal technique, the remaining wall thickness is at least equal to
the design minimum wall thickness.
Figure C.1 — Cut or gouge Figure C.2 — Crack
Figure C.3 — Fire damage Figure C.4 — Arc or torch burns
Figure C.5 — General corrosion Figure C.6 — Line corrosion Figure C.7 — Isolated pits
Annex D
(normative)
Procedure to be adopted when a cylinder valve
is suspected to be
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