ISO 7005-2:1988 金属フランジ—パート2：鋳鉄フランジ | ページ 2

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.

Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the ISO Council. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting.

International Standard ISO 7005-2 was prepared by Technical Committee ISO/TC 5, Ferrous metal pipes and metallic fittings.

This part of ISO 7005, together with parts 1 and 3, cancel and replace ISO 2084: 1974, ISO 2229: 1973 and ISO 2441: 1975.

ISO 7005 will consist of the following parts, under the general title Metallic flanges:

• Part 1: Steel flanges
• Part 2: Cast iron flanges
• Part 3: Copper alloy and composite flanges
• Part 4: Aluminium and aluminium alloy flanges

Annexes A and B of this part of ISO 7005 are for information only.

Introduction

Various flange systems based on differing design criteria have been in use throughout the world for many years. Given the increasing difficulties arising from such a situation, this International Standard has been based on a single series of metallic flanges. ISO 7005 will be published in four parts as follows:

Part 1: Steel flanges

Part 2: Cast iron flanges

Part 3: Copper alloy and composite flanges

Part 4: Aluminium and aluminium alloy flanges

This part of ISO 7005 is based on the American and European cast iron flange systems which have been combined to produce one International Standard with some changes to the dimensions specified in the two systems.

The materials specified in American (ANSI) standards and International Standards have been retained. Because, at this time, the International Standards for cast iron materials do not specify pressure/temperature (p/T) ratings, the ratings for the materials specified have been based on those given in comparable national standards.

In the American system, flanges are designated by a Class rating but in this part of ISO 7005 the relevant Class ratings are designated by nominal pressure (PN) ratings. The equivalent designations are as follows:

Classes 125 and 150: ISO PN20

Classes 250 and 300: ISO PN50

The ratings used in the European system remain as ISO PN2,5, ISO PN6, ISO PN10, ISO PN16, ISO PN25 and ISO PN40.

ISO PN20 and ISO PN50 grey cast iron and ductile cast iron flanges are designed to be interchangeable with flanges to ANSI B16.1 (grey cast iron) and ANSI B16.42 (ductile cast iron). They are not identical but are deemed to comply with the dimensions specified in ANSI B16.1 and ANSI B16.42 as appropriate (see 2.7).

Flange details in all four parts of ISO 7005 are such that flanges having the same PN and nominal size (DN) values and compatible flange facings will mate together when using metric bolting. Tolerances on dimensions are given for guidance in annex A.

To avoid any possible confusion in giving descriptive names to flanges, all flanges are designated by type numbers and flange facings are designated by a letter.

Users of this part of ISO 7005 should satisfy themselves that the flanges comply with any statutory requirements.

Annex B

Bibliography