ISO 7121:2016 汎用産業用鋼球バルブ | 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.

The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, 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, 2 (see www.iso.org/directives ).

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The committee responsible for this document is ISO/TC 153, Valves.

This third edition cancels and replaces the second edition (ISO 7121:2006), which has been technically revised with the following changes:

• the scope DN 600, NPS 20 and 24, Class 800 and a note on the applicability of this Class were added;
• the normative references were updated;
• definitions for DN, NPS, PN and Class were added;
• a line for DN 600 was added in Table 2;
• a line for DN 600 and a column for Class 800 were added in Table 3;
• a column for DN 600 was added in Table 4;
• a column for Class 800 was added in Table 6;
• Tables 7 and 8, DN is up to 600;
• 5.2.12.3, vertically split glands are not allowed anymore; Annex A was updated accordingly;
• 8.2.2 on site inspection was deleted; Annex A was updated accordingly.

Introduction

The purpose of this International Standard is the establishment, in ISO format, of basic requirements and practices for flanged, butt-welding, socket welding and threaded-end steel ball valves having flow passageways identified as full bore, reduced bore and double reduced bore, suitable for general purpose applications. Flanged end Class designated valves have flanges in accordance with ASME B16.5. Flanged end PN designated valves have flanges in accordance with EN 1092-1. Valves with ends that are threaded can have threads to either ISO 7-1 or ASME B1.20.1.

1 Scope

This International Standard specifies the requirements for a series of steel ball valves suitable for general-purpose industrial applications.

It covers valves of the nominal sizes

• DN 8, 10, 15, 20, 25, 32, 40, 50, 65, 80, 100, 150, 200, 250, 300, 350, 400, 450, 500, and 600 (NPS 1/4, 3/8, 1/2, 3/4, 1, 11/4, 11/2, 2, 21/2, 3, 4, 6, 8, 10, 12, 14, 16, 18, 20 and 24),

and is applicable to the following pressure designations:

• PN 10; 16; 25; 40; 63; 100;
• Class 150; 300; 600; 800; 900.

It includes provisions for valve characteristics as follows:

• flanged and butt-welded ends in sizes 15 ≤ DN ≤ 600 (1/2 ≤ NPS ≤ 24);
• socket welding ends in sizes 8 ≤ DN ≤ 100 (1/4 ≤ NPS ≤ 4);
• threaded ends in sizes 8 ≤ DN ≤ 50 (1/4 ≤ NPS ≤ 2);
• body seat openings designated as full bore, reduced bore and double reduced bore;
• materials;
• testing and inspection.

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.

3 Terms and definitions

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

Bibliography