ISO 16438:2021

INTERNATIONAL ISO
STANDARD 16438
Second edition
2021-08
Agricultural irrigation equipment —
Thermoplastic collapsible hoses for
irrigation — Specifications and test
methods
Matériel agricole d'irrigation — Tuyaux écrasables en matières
thermoplastiques pour l'irrigation — Spécifications et méthodes
d'essai
Reference number
©
ISO 2021
© ISO 2021
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ii © ISO 2021 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Classification . 2
5 Material . 2
6 Marking . 3
7 Dimensions . 3
7.1 Inside diameter . 3
7.2 Length . 3
7.3 Spacing of outlet connections . 3
8 Fittings . 3
9 Hydrostatic and hydraulic characteristics . 3
9.1 Proof pressure test . 3
9.2 Deformation under pressure and after relaxation . 4
9.3 Warping . 4
9.4 Head loss . 4
10 Physical characteristics . 4
10.1 Opacity . 4
10.2 UV resistance . 5
Bibliography . 6
Foreword
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iso/ foreword .html.
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.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2021 – All rights reserved

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 cove
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