ISO 8779:2020

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 8779
ISO/TC 138/SC 2
Plastics piping systems —
Secretariat: SNV
Polyethylene (PE) pipes for irrigation
Voting begins on:
2020­05­20 — Specifications
Voting terminates on:
Systèmes de canalisations en plastique — Tubes en polyéthylène (PE)
2020­07­15
pour l'irrigation — Spécifications
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 8779:2020(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO 2020

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ISO/FDIS 8779:2020(E)

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© ISO 2020
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ii © ISO 2020 – All rights reserved

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ISO/FDIS 8779:2020(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Material . 3
4.1 General . 3
4.2 Use of reprocessable material . 4
4.3 Physical characteristics of the material . 4
4.4 Designation and classification . 5
5 Geometrical characteristics . 5
5.1 Measurements . 5
5.2 Mean outside diameter and out­of­roundness . 6
5.3 Wall thicknesses and their tolerances . 6
6 Mechanical characteristics . 7
6.1 Requirements . 7
6.2 Retest in case of failure at 80 °C . 9
7 Physical characteristics . 9
7.1 Requirements . 9
8 Marking .10
8.1 General .10
8.2 Minimum required marking of pipes .10
Annex A (informative) Effect of water temperature on the maximum allowable working
pressure of irrigation pipe .12
Bibliography .13
© ISO 2020 – All rights reserved iii

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ISO/FDIS 8779:2020(E)

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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 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, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for
the transport of fluids, Subcommittee SC 2, Plastics pipes and fittings for water supplies.
This fourth edition cancels and replaces the third edition (ISO 8779:2010), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— The scope of this fourth edition has been modified to cover larger sizes of mains and sub-mains of
irrigation piping system.
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.
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ISO/FDIS 8779:2020(E)

Introduction
The aim of this document is to specify the minimum requirements from polyethylene irrigation pipes
that stay idle most of their life and are only pressurized for short periods from time to time. This
condition is true for the majority of irrigation pipes in use, including laterals, submains and even mains.
The normal conditions of use of irrigation pipes, as well as other important factors, differ widely from
those of pipes used for long-term water distribution systems (according to the ISO 4427 series):
— Pressure regime: pressure is applied intermittently for short periods, adding up to maximum 15 %
of any long period of time.
— Installation location: most pipes are laid above ground in fields, exposed to chemicals, soil cultivation
operations, being stepped on, being run over by tractors, etc.
— Non-permanent connections: pipes are connected by removable and re-installable mechanical
compression fittings, not by permanent fusion techniques.
— Movability: pipelines may be moved (manually or towed) between several locations in the field;
they may also be dis-assembled at season's end and re-assembled at the beginning of next season.
— End of life is mostly caused by external effects, mechanical or environmental, and not by failure
under pressure.
— Lifetime expectancy is, consequently, much shorter – ten years maximum.
— Colours: pipes may be produced in non-black colours (e.g. violet – for irrigation by reclaimed water).
— Lower risk: a failure in an irrigation pipe has much lower impact, compared to a failure in long­term
water distribution pipes.
Considering all factors above, the classification of pipe material in this document is by resistance to
a standard series of pressure tests, rather than according to ISO 12162 (which relates to pipes under
continuous pressure for 50 years), and material designation is therefore different. As explained above,
fusion compatibility is not required either. Otherwise, this document follows ISO 4427-2 with regard to
dimensions and test requirements.
In order to clearly restrict the use of this document to those pipes that fit the description above, the
Scope specifies a usage limit of a maximum of 1 500 hours under pressure per year. For applications
where pipes exceed or may exceed this limit, pipes complying with the ISO 4427 series should be
selected.
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 8779:2020(E)
Plastics piping systems — Polyethylene (PE) pipes for
irrigation — Specifications
1 Scope
This document specifies the characteristics of pipes (mains, sub-mains and laterals) made from
polyethylene (PE), intended for the conveyance of water for irrigation, at a water temperature up to 45 °C.
NOTE 1 For the effect of water temperature on the maximum operating pressure see Annex A.
This document applies to pipes that will not be subjected to internal pressure for long periods, and not
more than 1 500 hours/year. For piping applications with long-term continuous pressure the ISO 4427
series applies.
NOTE 2 The expected lifetime of pipes covered by this document is ten years or less.
This document also specifies the properties of the material and the parameters for the test methods to
which it refers.
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.
ISO 1133­1, Plastics — Determination of the melt mass-flow rate (MFR) and melt volume-flow rate (MVR)
of thermoplastics — Part 1: Standard method
ISO 1167­1, Thermoplastics pipes, fittings and assemblies for the conveyance of fluids — Determination of
the resistance to internal pressure — Part 1: General method
ISO 1167­2, Thermoplastics pipes, fittings and assemblies for the conveyance of fluids — Determination of
the resistance to internal pressure — Part 2: Preparation of pipe test pieces
ISO 2505, Thermoplastics pipes — Longitudinal reversion — Test method and parameters
ISO 3126, Plastics piping systems — Plastics components — Determination of dimensions
ISO 6964, Polyolefin pipes and fittings — Determination of carbon black content by calcination and
pyrolysis — Test method
ISO 8796, Polyethylene PE 32 and PE 40 pipes for irrigation laterals — Susceptibility to environmental
stress cracking induced by insert-type fittings — Test method and requirements
ISO 11357­6, Plastics — Differential scanning calorimetry (DSC) — Part 6: Determination of oxidation
induction time (isothermal OIT) and oxidation induction temperature (dynamic OIT)
ISO 11922­1, Thermoplastics pipes for the conveyance of fluids — Dimensions and tolerances — Part 1:
Metric series
ISO 18553, Method for the assessment of the degree of pigment or carbon black dispersion in polyolefin
pipes, fittings and compounds
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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ISO/FDIS 8779:2020(E)

ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
main
main supply line within an irrigation system, including sub-mains
3.2
lateral
branch supply line within an irrigation system on which water distribution devices are mounted
directly or by means of fittings, risers or tubes
Note 1 to entry: Examples of water distribution devices are sprinklers, emitters and drippers.
3.3
melt mass-flow rate
MFR
value relating to the viscosity of the molten material at a specified temperature and load measured in
accordance with ISO 1133­1
Note 1 to entry: MFR is expressed in units of grams per 10 min (g/10 min).
3.4
nominal outside diameter
d
n
specified outside diameter, assigned to a nominal size DN/OD
Note 1 to entry: Expressed in millimetres.
3.5
mean outside diameter
d
em
value of the measurement of the outer circumference of the pipe or spigot end of a fitting in any cross-
section divided by π (= 3,142), rounded to the next greater 0,1 mm
3.6
minimum mean outside diameter
d
em, min
minimum value of the outside diameter as specified for a given nominal size
3.7
maximum mean outside diameter
d
em, max
maximum value of the outside diameter as specified for a given nominal size
3.8
out-of-roundness
ovality
difference between the measured maximum outside diameter and the measured minimum outside
diameter in the same cross-section of the pipe or spigot end of a fitting
3.9
nominal wall thickness
e
n
numerical designation of the wall thickness of a component, which is a convenient round number
approximately equal to the manufacturing dimension
Note 1 to entry: Expressed in millimetres.
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ISO/FDIS 8779:2020(E)

3.10
wall thickness at any point
e
value of the measurement of the wall thickness at any point around the circumference of a component
3.11
minim
...