ISO 7186:2011

INTERNATIONAL ISO
STANDARD 7186
Third edition
2011-07-15
Ductile iron products for sewerage
applications
Produits en fonte ductile pour l'assainissement

Reference number
©
ISO 2011
©  ISO 2011
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Published in Switzerland
ii © ISO 2011 – All rights reserved

Contents Page
Foreword .iv
1 Scope.1
2 Normative references.1
3 Terms and definitions .2
4 Technical requirements .7
4.1 General .7
4.2 Pressure classification .9
4.3 Dimensional requirements .9
4.4 Material characteristics.13
4.5 Coatings and linings for pipes.14
4.6 Coatings for fittings and accessories .14
4.7 Systems design requirements .15
4.8 Leaktightness of pipeline components.15
4.9 Marking.15
5 Performance requirements.16
5.1 Leaktightness of joints .16
5.2 Diametral stiffness .17
5.3 Chemical resistance.18
5.4 Abrasion resistance .18
6 Test methods and test frequencies .18
6.1 Dimensions .18
6.2 Straightness of pipes .19
6.3 Tensile test.19
6.4 Brinell hardness .21
6.5 Works leaktightness test of pipes and fittings for pressure applications .21
6.6 Works leaktightness test of pipes and fittings for vacuum applications .22
7 Type tests.22
7.1 Leaktightness of gravity pipeline components.22
7.2 Leaktightness of joints to internal pressure.22
7.3 Leaktightness of joints to external pressure.23
7.4 Leaktightness of joints to negative internal pressure.24
7.5 Diametral stiffness of pipe.24
7.6 Chemical resistance to effluents .26
7.7 Abrasion resistance .27
8 Tables of dimensions.28
8.1 Socket and spigot pipes .28
8.2 Fittings for gravity applications.30
8.3 Fittings for pressure and vacuum applications .32
Annex A (informative) External protection .33
Annex B (informative) Internal protection .34
Annex C (normative) Allowable pressure for pressure sewers .35
Bibliography.36

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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. 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.
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.
ISO 7186 was prepared by Technical Committee ISO/TC 5, Ferrous metal pipes and metallic fittings,
Subcommittee SC 2, Cast iron pipes, fittings and their joints.
This third edition cancels and replaces the second edition (ISO 7186:1996), which has been technically
revised. A new classification system for pipes and fittings based on pressure is introduced with minimum wall
thickness determined by allowable operating pressure.

iv © ISO 2011 – All rights reserved

INTERNATIONAL STANDARD ISO 7186:2011(E)

Ductile iron products for sewerage applications
1 Scope
This International Standard specifies the requirements and test methods applicable to ductile iron pipes,
fittings, accessories and their joints for the construction of drains and sewers outside buildings:
⎯ to convey surface water (e.g. rainwater), domestic waste water and/or certain types of industrial effluents,
either in separate systems or in combined systems;
⎯ operating without pressure (gravity sewers) or with positive or negative pressure;
⎯ for installation below or above ground.
1)
NOTE In this International Standard, all pressures are relative pressures expressed in bar .
This International Standard contains specifications for materials, dimensions and tolerances, mechanical
properties and standard coatings of pipes, fittings and accessories. It also gives performance requirements for
all components including joints.
This International Standard is applicable to pipes, fittings and accessories cast by any type of foundry process
or manufactured by fabrication of cast components, as well as corresponding joints, in the size range DN 80 to
DN 2600 inclusive.
It is applicable to pipes, fittings and accessories which are
⎯ manufactured with socketed, flanged or spigot ends (joint design and gasket shape are outside the scope
of this International Standard), and
⎯ normally delivered internally and externally coated.
2 Normative references
The following referenced documents are indispensable for the application 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 2531, Ductile iron pipes, fittings, accessories and their joints for water applications
ISO 4016, Hexagon head bolts — Product grade C
ISO 4034, Hexagon nuts — Product grade C
ISO 4633, Rubber seals — Joint rings for water supply, drainage and sewerage pipelines — Specification for
materials
ISO 6506-1, Metallic materials — Brinell hardness test — Part 1: Test method

1) 100 kPa = 1 bar = 0,1 MPa; 1 MPa = 1 N/mm .
ISO 7005-2, Metallic flanges — Part 2: Cast iron flanges
ISO 7091, Plain washers — Normal series — Product grade C
ISO 10804, Restrained joint systems for ductile iron pipelines — Design rules and type testing
EN 1092-2, Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories,
PN designated — Part 2: Cast iron flanges
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
ductile iron
type of cast iron used for pipes, fittings and accessories in which graphite is present primarily in spheroidal
form
[ISO 2531:2009, definition 3.8]
3.2
pipe
casting of uniform bore, with straight axis, having either socket, spigot or flanged ends
NOTE This does not apply to flanged sockets, flanged spigots and collars, which are classified as fittings.
[ISO 2531:2009, definition 3.22]
3.3
fitting
casting other than a pipe, which allows pipeline deviation, change of direction or bore
NOTE Flanged sockets, flanged spigots and collars are also classified as fittings.
[ISO 2531:2009, definition 3.9]
3.4
accessory
any casting other than a pipe or fitting, which is used in a pipeline
EXAMPLE 1 Glands and bolts for mechanical flexible joints.
EXAMPLE 2 Glands, bolts and locking rings or segments for restrained joints.
[ISO 2531:2009, definition 3.1]
3.5
inspection chamber
component of a discharge system, of a drain or of a sewer providing access from the ground surface for
inspection and maintenance equipment
3.6
manhole
component of a sewer of sufficient size to provide access from the ground surface for inspection and
maintenance operations by personnel and equipment
2 © ISO 2011 – All rights reserved

3.7
flange
end of a pipe or fitting, extending perpendicular to its axis, with bolt holes equally spaced on a circle
NOTE A flange can be fixed (e.g. integrally cast, screwed-on or welded-on) or adjustable. An adjustable flange
comprises a ring, in one or several parts bolted together, which bears on an end joint hub and can be freely rotated around
the barrel axis before jointing.
[ISO 2531:2009, definition 3.10]
3.8
spigot
male end of a pipe or fitting
[ISO 2531:2009, definition 3.26]
3.9
spigot end
maximum insertion depth of the spigot, L , plus 50 mm
i
[ISO 2531:2009, definition 3.27]
See Figure 5.
3.10
socket
female end of a pipe or fitting to make the connection with the spigot of the next component
[ISO 2531:2009, definition 3.25]
3.11
gasket
sealing component of a joint
[ISO 2531:2009, definition 3.13]
3.12
joint
connection between the ends of pipes and/or fittings in which a gasket is used to effect a seal
[ISO 2531:2009, definition 3.15]
3.13
flexible joint
joint providing significant angular deflection and movement parallel and/or perpendicular to the pipe axis
[ISO 2531:2009, definition 3.12]
3.14
push-in flexible joint
flexible joint assembled by pushing the spigot through the gasket into the socket of the mating component
[ISO 2531:2009, definition 3.23]
3.15
mechanical flexible joint
flexible joint in which sealing is obtained by applying pressure to the gasket by mechanical means, e.g. a
gland
[ISO 2531:2009, definition 3.18]
3.16
restrained joint
joint in which a means is provided to prevent separation of the assembled joint
[ISO 2531:2009, definition 3.24]
3.17
flanged joint
joint between two flanged ends
[ISO 2531:20
...