ISO 4433-1:1997 熱可塑性プラスチックパイプ—液体化学物質に対する耐性—分類—パート1：浸漬試験方法 | ページ 2

1.1 ISO 4433 のこの部分では、輸送される液体化学薬品に関連した熱可塑性プラスチックパイプの挙動の予備評価を実行する方法を指定しています。

1.2この分類方法は、土荷重、動的応力、内部応力などの圧力や応力がない状態での液体化学薬品の輸送に対するパイプの適合性に関する情報を提供します。

1.3試験を実施するための完全な手順は、ISO 175 にも報告されています。ISO 175 は、熱可塑性プラスチックパイプに特化したものではなく、プラスチック全般に特化しています。

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 nongovernmental, 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.

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.

International Standard ISO 4433-1 was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for the transport of fluids, Subcommittee SC 3, Plastics pipes and fittings for industrial applications.

Together with the other parts (see below), this part of ISO 4433 cancels and replaces ISO 4433:1984, which has been technically revised.

ISO 4433 consists of the following parts, under the general title Thermoplastics pipes — Resistance to chemical fluids — Classification:

• Part 1: Immersion test method
• Part 2: Polyolefin pipes
• Part 3: Unplasticized poly(vinyl chloride) (PVC-U), high-impactpoly(vinyl chloride) (PVC-HI) and chlorinated poly(vinyl chloride)(PVC-C) pipes
• Part 4: Poly(vinylidene fluoride) (PVDF) pipes

Annexes A to C of this part of ISO 4433 are for information only.

Introduction

Because of their varied applications, thermoplastics pipes are frequently required to convey or be in contact with materials such as chemical products, fuels, lubricants, and sometimes their vapours.

Under the action of a liquid, the wall of a thermoplastics pipe can be the location for several concurrent phenomena; on the one hand, absorption of liquid and/or extraction of its soluble constituents from the pipe walls into the liquid; on the other hand, a chemical reaction usually involving a significant change in the properties of the pipe. The phenomena also differ according to the external and internal stresses affecting the pipes conveying the products (e.g. temperature, pressure, wall thickness).

By stresses are meant those forces caused by internal or external factors such as temperature, variation of temperature, inside pressure, bending, internal stresses. Internal stresses could be caused, for instance, by fast quenching of thick-walled pipes.

As the conditions of use vary a great deal, it is important to carry out a preliminary determination of the chemical resistance of thermoplastics pipes by means of simple, straightforward tests.

The purpose of this International Standard is to provide a procedure for the experimental test methods.

Some liquids (e.g. wetting agents) may cause cracking in specimens subject to tensile stress, whilst not affecting the properties of specimens not under stress. The strip bending test as specified in ISO 4599 ^[3] (see annex C) or the constant tensile stress method as specified in ISO 6252 ^[4] will give an indication of the susceptibility of the material to stress cracking. For polyolefin materials, attention is also drawn to ISO 13480 ^[7] .

The extrapolation of the results obtained with this method, expressed as:

for any kind of pipe or fitting may be made only when high internal stresses are not induced in the pipe.

In order to assess the behaviour of pipes and fittings for the conveyance of liquids under pressure or in the presence of other stresses, in cases when the preliminary classification is S or L, it will be necessary to carry out further tests as specified in ISO 8584-1 ^[5] .

1 Scope

2 Normative references

The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO 4433. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO 4433 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards.

Annex C

Bibliography