ISO 16438:2021 農業用灌漑設備—灌漑用の熱可塑性折りたたみ式ホース—仕様と試験方法 | ページ 2

Foreword

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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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This document was prepared by Technical Committee ISO/TC 23, Tractors and machinery for agriculture and forestry, Subcommittee SC 18, Irrigation and drainage equipment and systems.

This second edition cancels and replaces the first edition (ISO 16438:2012), which has been technically revised.

The main changes compared to the previous edition are as follows:

• PVC layflat hoses are excluded from this document;
• some definitions have been updated;
• some changes in pressure tests parameters and procedure have been applied;
• marking the word"irrigation" became optional.

Introduction

Thermoplastic collapsible hoses have been introduced to agricultural irrigation projects in recent years, as headers supplying drip tape systems or as replacement for gated pipes.

Thermoplastic collapsible hoses for irrigation are a special type of hoses. They have a unique combination of attributes and requirements which must be well specified and controlled, but are not covered by any other International Standard:

• equal and accurate spacing of multiple water outlet connections along their length;
• low elongation and amount of twist while under pressure;
• resistance to most fertilizers and other chemicals employed in irrigation;
• protection against degradation by UV radiation;
• impermeability of wall to incident light;
• information of pressure loss data.

This document is intended to cover all those aspects, by specifying the requirements and the applicable test methods.

1 Scope

This document specifies requirements and test methods for reinforced and non-reinforced thermoplastic collapsible hoses, intended to be used as main and sub-main supply lines for the conveyance and distribution of water for irrigation, at water temperatures up to 50 °C. PVC layflat hoses are excluded from this document.

It is applicable to irrigation hoses with nominal diameters between 40 mm and 500 mm and working pressures between 0,3 bar (30 kPa) and 6 bar (600 kPa).

This document is applicable to two types of hose configurations, with or without outlet connections (see Clause 4).

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 following terms and definitions apply.

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

Bibliography