ISO 11419:1997
(Main)Agricultural irrigation equipment — Float type air release valves
Agricultural irrigation equipment — Float type air release valves
Matériel agricole d'irrigation — Vannes de purge d'air à flotteur
General Information
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 11419
First edition
1997-12-01
Agricultural irrigation equipment — Float
type air release valves
Matériel agricole d'irrigation — Vannes de purge d'air à flotteur
A
Reference number
ISO 11419:1997(E)
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ISO 11419:1997(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 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 voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard ISO 11419 was prepared by Technical Committee
ISO/TC 23, Tractors and machinery for agriculture and forestry,
Subcommittee SC 18, Irrigation and drainage equipment and systems.
© ISO 1997
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
International Organization for Standardization
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Printed in Switzerland
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INTERNATIONAL STANDARD ISO ISO 11419:1997(E)
Agricultural irrigation equipment — Float type air release
valves
1 Scope
This International Standard gives the structural and operational requirements and test methods for float-type air
release valves, hereinafter referred to as air release valves. These valves are intended for operation in irrigation
systems with water whose temperature does not exceed 60 °C, and which may contain chemicals of the types and
concentrations generally in use in irrigation.
This International Standard applies to air release valves, with a nominal size of 15 mm (1/2 inch) to 150 mm
(6 inch), which are operated by a float which acts as the sealing member or which directly activates the sealing
member.
This International Standard applies to air release valves which are intended to allow entry of air into the pipe system
from the atmosphere (“vacuum relief”) and/or release of air from the pipe system to the atmosphere.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this
International Standard. At the time of publication, the editions indicated were valid. All standards are subject to
revision, and parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
ISO 7-1:1994, Pipe threads where pressure-tight joints are made on the threads — Part 1: Dimensions, tolerances
and designation.
ISO 2859-1:1989, Sampling procedures for inspection by attributes — Part 1: Sampling plans indexed by
acceptable quality level (AQL) for lot-by-lot inspection.
ISO 7005-1:1992, Metallic flanges — Part 1: Steel flanges.
3 Definitions
For the purposes of this International Standard, the following definitions apply.
3.1 air release valve: Valve which opens automatically to allow air from the atmosphere to enter the pipeline
during drainage of the pipeline and/or venting of air from the water pipeline to the atmosphere during filling or during
normal operation of the pipeline under pressure.
3.2 dual triple-function air release valve: Air release mechanism which consists of two valves, a high-pressure
continuous-acting air release valve (3.4) and a low-pressure air release valve (3.6), which are housed in one unit
but operate separately in accordance with their functions.
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ISO 11419:1997(E)
NOTE — A dual triple-function air release valve fulfils the following functions:
— it enables continuous release of air from the pipe system at working pressure;
— it allows entry of air at a high flow rate during drainage of water from the pipe system; and
— it allows release of air at a high flow rate when the pipe system is being filled with water.
3.3 float; float assembly: Component within the valve body whose specific weight is less than that of water and
is intended to float upon the water filling the cavity of the valve body.
NOTE — When the float seals at the relief nozzle (either directly or by means of a part of the float assembly), the force acting
on the float (or the elevating force) and the other forces which develop within the valve seal the relief nozzle and prevent water
from flowing out of the air release valve.
3.4 high-pressure continuous-acting air release valve: Air release valve with a small cross-sectional relief
nozzle which releases pockets of air trapped in the pipeline in proximity to the air release valve when the water
pipeline is under normal operating conditions (a prevailing hydraulic pressure within the normal working pressure
range of the water pipeline), and which allows entry of air into the pipeline at a pressure lower than or equal to
atmospheric pressure.
See figure 1 a).
3.5 inlet connection: Part of the inlet to the air release valve, or part of the valve body itself (in the bottom part of
the valve) which connects the air release valve to the pipeline.
3.6 low-pressure air release valve: Air release valve with a large cross-sectional relief nozzle that serves to vent
air trapped in the pipeline at high flow rates during filling of the pipeline and that allows entry of air at high flow rates
into the pipeline when draining.
See figure 1 b).
3.7 maximum working pressure: Highest pressure at the inlet of an air release valve at which the air release
valve is intended to open to release air from the pipeline or to allow entry of air.
3.8 minimum working pressure: Lowest pressure at the valve inlet at which complete sealing is obtained.
3.9 Maximum static pressure of the water at the inlet of an air release valve inlet which the air
nominal pressure:
release valve is stated to withstand under normal service conditions.
3.10 A conventional numerical designation used to indicate the size of the air release valve which
nominal size:
is identical to the nominal diameter or threaded size of pipe which can be connected to the air release valve without
an intermediate fitting.
NOTE — The nominal size of the air release valve is not related to the nominal diameter or nominal size of the pipeline from
which it is intended to release air or allow air to enter.
3.11 relief nozzle: Aperture in the upper part of the air release valve body (or in the valve cover plate) through
which air is vented from the valve, or into which air enters.
NOTE — In general, a relief nozzle serves also as the seat of the float.
3.12 sealing seat: Part of the relief nozzle (on the inside part of the valve body of an air release valve) against
which the float seals when the relief valve is closed and which acts as a seal.
3.13 valve body: Part of the air release valve through whose cavity the float moves.
3.14 inlet orifice: The point of the smallest passage area in the air release valve located below the valve float
when in the open position.
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ISO 11419:1997(E)
Key
1 Relief nozzle
2 Float
3 Valve body
4 Inlet connection
5 Protective covers
Figure 1 — Air release valve (schematic)
4 Classification
Air release valves are classified as follows.
4.1 According to purpose of the valve
— high-pressure continuous-acting air release valve;
— low-pressure air release valve;
— dual triple-function air release valve.
4.2 According to nominal pressure
— 1,0 MPa
— 1,6 MPa
— 2,5 MPa
5 Marking
Each air release valve shall bear a clear and durable marking which shall contain the following particulars:
a) name of manufacturer and/or the manufacturer's registered trade mark;
b) nominal size;
c) nominal pressure;
d) a marking which identifies the valve model according to its purpose, as defined in 4.1, and as specified in the
manufacturer's catalogue.
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ISO 11419:1997(E)
6 Technical characteristics
6.1 General
The parts of the air release valve coming in contact with water shall be of non-toxic materials, and shall be resistant
to, or protected against, corrosion under the normal working conditions at which the valve is intended to operate.
All parts of an air release valve of the same model and nominal pressure, and which are manufactured by one
manufacturer and which are intended to be removed, repaired or replaced, shall be interchangeable.
All parts of the air release valve which are made from plastics and which are exposed to ultraviolet radiation under
the normal operating conditions of the valve shall contain additives to improve their resistance to ultraviolet
radiation. Plastic parts of the valve which serve as water passages shall be opaque, or shall be protected in some
other manner (for instance, by a closed cover) against penetration of light to the water passages.
6.2 Components of the air release valve
6.2.1 The structure of the valve body and of the float shall ensure free movement of the float within the valve body
cavity, except for its upper position (completely closed) and its lower position (completely open), without the
possibility of the float being arrested in an intermediate position.
6.2.2 The area of contact with the sealing seat (when the float itself serves as the seal), or that part of the float
assembly which serves as a seal, shall be made of a material which shall ensure complete sealing when the air
release valve is closed.
6.2.3 Those parts which are activated to seal the air release valve shall be constructed so as to prevent seizure of
the valve in the open or closed position.
A low-pressure air release valve shall contain suitable means or shall be designed to prevent the float from
6.2.4
being pushed against the relief nozzle (so as to seal it) during the release of high air flows. The area of the air
passage in all parts of the low-pressure air release valve, shall be larger than the area of the inlet orifice.
6.2.5 The air release valve shall be designed to protect the relief nozzle from damage due to an accidental
external blow.
6.2.6 It shall be possible to dismantle the air release valve for purposes of maintenance and/or replacement of the
float and the relief nozzle, unless the air release valve is manufactured in such a manner so that it is not intended
for dismantling and that it is stated in the manufacturer's catalogue and/or information sheets that the air release
valve cannot be dismantled for maintenance and/or replacement of the float and relief nozzle.
6.2.7 In threaded air release valves, the valve body shall be equipped with a hexagonal boss or some other
suitable means of accommodating a wrench.
6.2.8 The air release valve shall perform correctly when installed within – 5° from a vertical position.
6.3 Connections
The inlet connection shall have one of the following means of connection for joining the air release valve to the
pipeline:
a) Threads for direct connection to the pipeline. The threads shall comply with ISO 7-1. However, other threads
are allowed provided that a suitable adaptor is supplied with each threaded connection such that it complies
with ISO 7-1.
b) Flanges which comply with ISO 7005-1.
c) Other forms of connection.
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ISO 11419:1997(E)
7 Construction and operating tests
7.1 General
For the purposes of the tests, the air release valves shall be connected to the test apparatus in a vertical position,
with an allowable deviation not greater than 2°.
Unless otherwise specified, all tests shall be conducted with clean water within a temperature range of 10 °C to
30 °C. The apparatus used for measuring the various parameters shall enable measurement with
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