ISO/TR 4673:2022 ガスシリンダー — 複合シリンダーおよびチューブの耐用年数性能 | ページ 2

Foreword

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This document was prepared by Technical Committee ISO/TC 58, Gas cylinders, Subcommittee SC 3, Cylinder design.

Introduction

Composite gas cylinders have been manufactured for more than 50 years. Over that time, several specifications have been developed at the national, regional and international levels.

The following ISO standards cover the design of composites cylinders and tubes:

• ISO 11119 series (cylinders and tubes up to 450 l);
• ISO 11515 (tubes from 450 l to 3 000 l).

When the above-mentioned standards were proposed for reference in the UN Model Regulations, a lot of discussion took place because the two main regions using composite gas cylinders (Europe and North America) had different approaches. In Europe, regulations permitted non-limited lifetime for composite cylinders, while in North America, the lifetime was limited to 15 years by the US Department of Transportation.

To reach consensus, the concept of a service life test programme for composite cylinders and composite tubes of more than 15 years design life time was incorporated into the United Nations Recommendations on the Transport of Dangerous Goods (The Orange Book), as adopted in the 19^th revision, in NOTE 2 of 6.2.2.1.1 and 6.2.2.1.2. This statement has raised several questions over the years:

• When are the tests to be performed?
• On which cylinders are the tests to be performed? How will the sampling be established?
• What tests are to be performed?
• Are all the tests really needed?
• Can the service life test programme be included in the design standard?

To answer these questions, ISO/TC 58/SC 3/WG 36 developed ISO/TR 19811. Indeed, to understand what testing programmes are in use by ISO P-member countries, competent authorities were asked to provide information regarding the composite cylinder approvals that are accepted in their country and any service life test programmes currently practiced.

The information received from the competent authorities was used to determine the similarities and differences in the service life test programmes used.

In 2018, ISO/TC 58/SC 3/AHG 1 concluded that there is no standardized global test protocol, and the worldwide feasibility of such programmes was difficult to put in place.

Finally in 2019, taking into account the previous work of ISO/TC 58/SC 3/WG 36 and ISO/TC 58/SC 3/AHG 1, ISO/TC 58/SC 3 asked WG 36 to develop a document to support the removal of service life test programme from the UN Model Regulations.

The aim of this proposed Technical Report was to build a rationale to answer the following question:

“Is a service life test programme needed to guarantee the safe and reliable performance of cylinders with a design life longer than 15 years?”

It is important to note that the current document deals only with the need (or not) of having a service life test programme for a cylinder with design life of more than 15 years or non-limited life to guarantee its “safety”.

1 Scope

This document collects history and experience of composite cylinders and tubes to be used under the International Regulations for the Transport of Dangerous Goods:

• with a water capacity up to 3 000 l;
• with a design life greater than 15 years.

In particular the document reviews the topic of the service life performance of existing composite cylinders and tubes and provides information and data for the following items:

• history of cylinder design;
• current testing regimes;
• significance of the tests on their performance;
• service performance including pre-fill and periodic inspection and tests.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

3 Terms and definitions

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

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

Bibliography