ISO/DIS 11515

Gas cylinders -- Refillable composite reinforced tubes of water capacity between 450 L and 3000 L -- Design, construction and testing

Bouteilles à gaz -- Tubes composites renforcés rechargeables d'une capacité de 450 L à 3000 L -- Conception, construction et essais

Standards Content (sample)

DRAFT INTERNATIONAL STANDARD
ISO/DIS 11515
ISO/TC 58/SC 3 Secretariat: BSI
Voting begins on: Voting terminates on:
2020-09-03 2020-11-26
Gas cylinders — Refillable composite reinforced tubes
of water capacity between 450 L and 3000 L — Design,
construction and testing

Bouteilles à gaz — Tubes composites renforcés rechargeables d'une capacité de 450 L à 3000 L —

Conception, construction et essais
ICS: 23.020.35
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
This document is circulated as received from the committee secretariat.
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 11515:2020(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. ISO 2020
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ISO/DIS 11515:2020(E)
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© ISO 2020

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ii © ISO 2020 – All rights reserved
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ISO/DIS 11515:2020(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Symbols .......................................................................................................................................................................................................................... 5

5 Inspection and testing .................................................................................................................................................................................... 5

6 Materials ....................................................................................................................................................................................................................... 5

6.1 Liner materials ........................................................................................................................................................................................ 5

6.2 Composite overwrap .......................................................................................................................................................................... 6

7 Design and manufacture .............................................................................................................................................................................. 7

7.1 General ........................................................................................................................................................................................................... 7

7.2 Design submission ............................................................................................................................................................................... 7

7.3 Manufacturing ......................................................................................................................................................................................... 9

8 Type approval procedure ............................................................................................................................................................................ 9

8.1 General ........................................................................................................................................................................................................... 9

8.2 Prototype tests ........................................................................................................................................................................................ 9

8.3 New design ..............................................................................................................................................................................................10

8.4 Design variants ....................................................................................................................................................................................11

8.5 Type approval test procedures and criteria ................................................................................................................16

8.5.1 Hydraulic proof pressure test ............................................................................................................................16

8.5.2 Hydraulic volumetric expansion test ..........................................................................................................16

8.5.3 Liner burst test ...............................................................................................................................................................17

8.5.4 Tube burst test ................................................................................................................................................................17

8.5.5 Ambient cycle test ........................................................................................................................................................18

8.5.6 Environmental cycle test........................................................................................................................................19

8.5.7 Flaw test ...............................................................................................................................................................................20

8.5.8 Blunt impact test ...........................................................................................................................................................22

8.5.9 Fire resistance test ......................................................................................................................................................24

8.5.10 Neck strength test ........................................................................................................................................................25

8.5.11 Leak test ...............................................................................................................................................................................26

8.5.12 Accelerated stress rupture test ........................................................................................................................26

8.5.13 Permeability test ...........................................................................................................................................................27

8.5.14 Gas cycle test ....................................................................................................................................................................27

8.5.15 Coatings test......................................................................................................................................................................29

8.5.16 Salt spray test ...................................................................... .............................................................................................29

8.5.17 Acid environment test ..............................................................................................................................................30

8.5.18 Vacuum test .......................................................................................................................................................................30

8.5.19 High velocity impact (gunfire) test ...............................................................................................................31

8.5.20 Glass transition temperature .............................................................................................................................31

8.6 Failure of type approval tests ..................................................................................................................................................31

9 Inspection and testing at time of manufacture ..................................................................................................................31

9.1 Liners for Type 2 and Type 3 tubes ....................................................................................................................................31

9.2 Liners for Type 4 tubes .................................................................................................................................................................32

9.3 Failure of liner batch tests ..........................................................................................................................................................33

9.4 Overwrap materials .........................................................................................................................................................................33

9.5 Composite tube ....................................................................................................................................................................................34

9.6 Failure of batch tests .......................................................................................................................................................................34

10 Tube marking ........................................................................................................................................................................................................35

10.1 General ........................................................................................................................................................................................................35

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ISO/DIS 11515:2020(E)

10.2 Additional marking ..........................................................................................................................................................................35

Annex A (informative) Examples of design approval certificate ..........................................................................................36

Annex B (informative) Specimen test reports ..........................................................................................................................................37

Annex C (normative) Ultrasonic inspection for seamless steel liners and metal tubing ............................39

Annex D (Informative) Guidance for calculating permeation rates when using trace gases ..................44

Bibliography .............................................................................................................................................................................................................................45

iv © ISO 2020 – All rights reserved
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ISO/DIS 11515:2020(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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2. www .iso .org/ directives

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. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received. www .iso .org/ patents

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

The committee responsible for this document is ISO/TC 58, Gas cylinders, Subcommittee SC 3,

Cylinder design.
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ISO/DIS 11515:2020(E)
Introduction

The purpose of ISO 11515 is to provide a specification for the design, manufacture, inspection and

testing of composite tubes for worldwide usage. The objective is to balance design and economic

efficiency against international acceptance and universal utility.

ISO 11515 aims to eliminate the concern about climate, duplicate inspection and restrictions currently

existing because of lack of definitive International Standards and should not be construed as reflecting

on the suitability of the practice of any nation or region.

ISO 11515 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.
Annexes A and B of ISO 11515 are for information only.
vi © ISO 2020 – All rights reserved
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DRAFT INTERNATIONAL STANDARD ISO/DIS 11515:2020(E)
Gas cylinders — Refillable composite reinforced tubes
of water capacity between 450 L and 3000 L — Design,
construction and testing
1 Scope

This document specifies minimum requirements for the materials, design, construction and

performance testing for:
— type 2 hoop wrapped composite tubes
— type 3 fully wrapped composite tubes
— type 4 fully wrapped composite tubes

— with water capacities between 450 l and 3 000 l for storage and conveyance of compressed or

liquefied gases with test pressures up to and including 1600 bar and a design life of at least 15 years.

The expected service temperatures are between −40 °C and +65 °C.

Type 4 tubes manufactured and tested to this document are not intended to contain toxic, oxidizing or

corrosive gases.

This document is limited to tubes with composite reinforcement of carbon fibre or aramid fibre or glass

fibre (or a mixture thereof) in a matrix.

Composite tubes can be used alone or in batteries to equip trailers or skids (ISO modules) or multiple

element gas containers (MEGC) for the transportation and distribution of gases. This document does

not include consideration of any additional stresses that can occur during service or transport, (e.g.

torsional / bending stresses). However, it is important that the stresses associated with mounting the

tube are considered by the assembly manufacturer and the tube manufacturer.
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

ISO 306, Plastics — Thermoplastic materials — Determination of Vicat softening temperature (VST)

ISO 527-1, Plastics — Determination of tensile properties — Part 1: General principles

ISO 527-2, Plastics — Determination of tensile properties — Part 2: Test conditions for moulding and

extrusion plastics

ISO 3341, Textile glass — Yarns — Determination of breaking force and breaking elongation

ISO 4624, Paints and varnishes — Pull-off test for adhesion
ISO 6506-1, Metallic materials — Brinell hardness test — Part 1: Test method
ISO 6508-1, Metallic materials — Rockwell hardness test — Part 1: Test method

ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature

ISO 7225, Gas cylinders — Precautionary labels
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ISO/DIS 11515:2020(E)

ISO 7866, Gas cylinders — Refillable seamless aluminium alloy gas cylinders — Design, construction

and testing
ISO 9227:2012, Corrosion tests in artificial atmospheres — Salt spray tests

ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel

ISO 9809-1, Gas cylinders — Design, construction and testing of refillable seamless steel gas cylinders and

tubes — Part 1: Quenched and tempered steel cylinders and tubes with tensile strength less than 1 100 MPa

ISO 9809-2, Gas cylinders — Design, construction and testing of refillable seamless steel gas cylinders and

tubes — Part 2: Quenched and tempered steel cylinders and tubes with tensile strength greater than or

equal to 1 100 MPa

ISO 9809-3, Gas cylinders — Design, construction and testing of refillable seamless steel gas cylinders and

tubes — Part 3: Normalized steel cylinders and tubes
ISO 10286, Gas cylinders - Terminology

ISO 10618, Carbon fibre — Determination of tensile properties of resin-impregnated yarn

ISO 11114-1, Gas cylinders — Compatibility of cylinder and valve materials with gas contents — Part 1:

Metallic materials

ISO 11114-2, Gas cylinders — Compatibility of cylinder and valve materials with gas contents — Part 2:

Non-metallic materials

ISO 11120, Gas cylinders — Refillable seamless steel tubes of water capacity between 150 l and 3000 l —

Design, construction and testing
ISO 13341, Gas cylinders — Fitting of valves to gas cylinders
ISO 13769, Gas cylinders — Stamp marking

ISO 14130, Fibre-reinforced plastic composites — Determination of apparent interlaminar shear strength

by short-beam method

ASTM D 522-93a, Standard Test Methods for Mandrel Bend Test of Attached Organic Coatings

ASTM D1308, Standard Test Method for Effect of Household Chemicals on Clear and Pigmented Organic

Finishes

ASTM D2794, Standard Test Method for Resistance of Organic Coatings to the Effects of Rapid Deformation

(Impact)
ASTM D3170, Standard Test Method for Chipping Resistance of Coatings
ASTM D7269, Standard Test Methods for Tensile Testing of Aramid Yarns

ASTM E1356–08,Standard Test Method for Assignment of the Glass Transition Temperatures by Differential

Scanning Calorimetry
3 Terms and definitions

For the purposes of this document, the terms and definitions in ISO 10286 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at https:// www .iso .org/ obp
2 © ISO 2020 – All rights reserved
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ISO/DIS 11515:2020(E)
3.1
aramid fibre
continuous filaments of aramid laid up in tow form, used for reinforcement
3.2
autofrettage

pressure application procedure which strains the metal liner past its yield point sufficient to cause

permanent plastic deformation, and results in the liner having compressive stresses and the fibres

having tensile stresses when at zero internal gauge pressure
3.3
batch
collective term for a set of homogeneous items or material

Note 1 to entry: The number of items in a batch can vary according to the context in which the term is used.

3.4
batch of load sharing liners

quantity of liners of the same nominal diameter, length, thickness and design, made successively from

the same material cast (heat) and processed in the same heat treatment equipment (i.e. a continuous

furnace process or a single furnace charge) using the same heat treatment parameters

3.5
batch of non-metallic liners

quantity of non-metallic liners of the same nominal diameter, length, thickness and design, made

successively and subjected to the same continuous manufacturing process
3.6
batch of metal bosses

quantity of metal bosses of the same nominal diameter, length, thickness and design, made successively

from the same material cast (heat) and processed in the same heat treatment equipment using the same

heat treatment parameters
3.7
batch of finished tubes

production quantity of up to 200 finished tubes successively produced (plus finished tubes required for

destructive testing), of the same nominal diameter, length, thickness and design

Note 1 to entry: The batch of finished tubes can contain different batches of liners, fibres and matrix materials.

3.8
burst pressure
highest pressure reached in a tube or liner during a burst test
3.9
carbon fibre
continuous filaments of carbon laid up in tow form, used for reinforcement
3.10
composite overwrap

combination of fibres and matrix used to reinforce the tube, including any barrier or protective layers

that are a permanent part of the design
3.11
dedicated gas service
service in which a tube is to be used only with specified gas or gases
3.12
equivalent fibre

fibre from the same material family and similar properties to a fibre used in a previously prototype

tested tube
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ISO/DIS 11515:2020(E)
3.13
equivalent liner

liner manufactured from the same nominal raw materials, using the same process of manufacture and

having the same physical structure and the same nominal physical properties (within ± 5 %) of the

approved liner design
3.14
equivalent matrix

resin matrix from the same chemical family and similar properties to the resin matrix used in a

previously prototype tested cylinder
3.15
exterior coating
layers of material applied to the tube as protection or for cosmetic purposes
Note 1 to entry: The coating can be transparent or opaque.
3.16
glass fibre
continuous filaments of glass laid up in tow form, used for reinforcement
3.17
leak

escape of gas at a rate greater than 5×10 mbar.l/s through a defect rather than permeation

3.18
liner

inner portion of the composite tube, whose purpose is both to contain the gas and transmit the gas

pressure to the fibres
3.19
load sharing liner

liner that has a burst pressure greater than or equal to 5 % of the nominal burst pressure of the finished

composite tube
3.20
non-load-sharing liner
liner that provides no load sharing for the finished composite tube
3.21
matrix
material that is used to bind and hold the fibres in place
3.22
minimum design burst pressure

minimum burst pressure specified by the manufacturer and that shall be achieved during a burst test

3.23
representative composite tube

a shorter tube with the same nominal diameter, and manufactured using the same materials and

manufacturing technique, and using a representative wrapping pattern (same number of strands and

same number of layers) so as to represent an equivalent stress compared to a full scale prototype

3.24
tube
transportable pressure receptacle of a water capacity exceeding 150 litres
3.25
tubing

hollow cylindrical body of metal or other material, used for conveying or containing liquids or gases

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ISO/DIS 11515:2020(E)
3.26
type 2 tube

hoop wrapped tube with a load sharing metal liner and composite reinforcement on the cylindrical

portion only
3.27
type 3 tube

fully wrapped tube with a load sharing metal liner and composite reinforcement on both cylindrical

portion and dome ends
3.28
type 4 tube

fully wrapped tube with a non-metallic, non-load-sharing liner and composite reinforcement on both

cylindrical portion and dome ends
3.29
glass transition temperature Tg

the temperature where a polymer substrate changes from a rigid glassy material to a soft (not melted)

material, and is usually measured in terms of the stiffness, or modulus
4 Symbols
p Burst pressure of finished tube bar
p Test pressure bar
p Maximum developed pressure at 65 °C bar
max
p Working pressure bar
5 Inspection and testing

ISO 11515 is intended to be used under a variety of national regulatory regimes but has been written

so that it is suitable for use with the conformity assessment system of the UN Model Regulations for the

Transportation of Dangerous Goods. Attention is drawn to requirements in specified relevant national

regulations of the country (countries) where the tubes are intended to be used that might override the

requirements given in this document. To ensure that the tubes conform to this document, they shall

be subject to inspection and testing in accordance with Clauses 6, 7, 8 and 9 by an inspection body

(hereafter referred to as “the inspector”) authorized to do so.

Tests and examinations performed to demonstrate compliance with this document shall be conducted

using instruments calibrated before being put into service and thereafter according to an established

programme.
6 Materials
6.1 Liner materials

6.1.1 Load sharing liner materials shall conform in all relevant respects to the appropriate International

Standards:

a) seamless steel liners: ISO 9809-1, ISO 9809-2, ISO 9809-3 or ISO 11120 as appropriate;

b) seamless aluminium alloy liners: ISO 7866.
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ISO/DIS 11515:2020(E)

Relevant sections are those covering materials, thermal treatments, neck design, construction and

workmanship, mechanical tests. Design requirements are excluded since these are specified by the

manufacturer for the design of the composite tube (see 7.2.2).

6.1.1.1 The composite tube manufacturer shall verify that each new batch of materials has the

specified properties and qualities, and shall maintain records so that the cast of material and the heat

treatment batch (where applicable) used for the manufacture of each tube can be identified. A certificate

of conformance from the liner material manufacturer is considered acceptable for the purposes of

verification.

6.1.1.2 The liner shall be manufactured from a metal or alloy suitable for the gas to be contained in

accordance with ISO 11114-1.

6.1.1.3 When a neck ring is provided, it shall be of a material compatible with that of the tube, and

shall be securely attached by a method appropriate to the liner material.

6.1.1.4 Non-load-sharing liner materials shall conform in all relevant respects to the appropriate

standards, as follows:

a) The liner (including metal boss) shall be manufactured from a material suitable for the gas to be

contained in accordance with ISO 11114-1 and ISO 11114-2 or demonstrated and documented by

suitable testing.

b) Metal bosses attached to a non-metallic liner shall fulfil the type approval testing requirements of

this document.

c) The tensile yield strength and ultimate elongation of plastic liner material shall be determined at

−50 °C in accordance with ISO 527-2.The test results shall demonstrate the ductile properties of

the plastic liner material at temperatures of −50 °C or lower by meeting the values specified by the

manufacturer.

d) Polymeric materials from finished liners shall be tested in accordance with a method described in

ISO 306. The softening temperature shall be at least 100 °C.
6.2 Composite overwrap

6.2.1 The overwrap filament materials shall be carbon fibre or aramid fibre or glass fibre (or any

mixture thereof).

NOTE Glass fibre reinforced composite tubes can be susceptible to chemical attack and degradation after

being in contact with aggressive acids (e.g. battery acid).

6.2.2 The resin matrix shall be a polymer suited to the application, environment and intended life of the

product, e.g. epoxy or modified epoxy with amine or anhydride curing agent, vinyl esters and polyesters.

6.2.3 The supplier of the filament material and the resin matrix system componen
...