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.
INTERNATIONAL STANDARD ISO 2531:2009 (E)
Ductile iron pipes, fittings, accessories and their joints for water 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 pipelines:
—
to convey water (e.g. for human consumption and raw water),
—
operated with or without pressure, and
—
installed below or above ground.
NOTE In this International Standard, all pressures are relative pressures expressed in bar 1).
This International Standard specifies 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 applies 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 40 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 shapes are outside the scope of this International Standard),
—
normally delivered internally and externally coated.
Pipes and fittings are classified according to allowable operating pressure.
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 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
ISO 7005-2, Metallic flanges — Part 2: Cast iron flanges
ISO 7091, Plain washers — Normal series — Product grade C
ISO 10803, Design method for ductile iron pipes
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
any casting other than a pipe or fitting, which is used in a pipeline
EXAMPLE
Glands and bolts for mechanical flexible joints (see
3.18).
EXAMPLE
Glands, bolts and locking rings or segments for restrained joints (see
3.24).
Note 1 to entry: The term accessory is not relevant for valves or hydrants of any type.
3.2
allowable operating pressure
maximum internal pressure, excluding surge, which a component can safely withstand in permanent service
3.3
allowable site test pressure
maximum hydrostatic pressure that a newly installed component can withstand for a relatively short duration, when either fixed above ground level or laid and backfilled underground, in order to measure the integrity and tightness of the pipeline
Note 1 to entry: This test pressure is different from the system test pressure, which is related to the design pressure of the pipeline.
3.4
quantity of castings from which a sample may be taken for testing purposes during manufacture
3.5
any product defined as an element of a pipe, fitting or accessory
<tbx:crossReference></tbx:crossReference><tbx:crossReference></tbx:crossReference><tbx:crossReference></tbx:crossReference> 3.6
amount by which the design length may differ from the standardized length of a pipe or a fitting
Note 1 to entry: Pipes and fittings are designed to a length selected in the range of standard length plus or minus the deviation (see Table 6); they are manufactured to this length plus or minus the tolerance given in Table 7.
3.7
diametral stiffness of a pipe
characteristic of a pipe allowing it to resist diametral deflection under loading
3.8
type of cast iron used for pipes, fittings and accessories in which graphite is present primarily in spheroidal form
3.9
casting other than a pipe, which allows pipeline deviation, change of direction or bore
Note 1 to entry: Flanged sockets, flanged spigots and collars are also classified as fittings.
3.10
end of a pipe or fitting, extending perpendicular to its axis, with bolt holes equally spaced in a circle
Note 1 to entry: 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 which can be freely rotated around the barrel axis before jointing.
3.11
joint between two flanged ends
3.12
joint providing significant angular deflection and movement parallel and/or perpendicular to the pipe axis
3.13
sealing component of a joint
3.14
stress in a pipe or fitting under pressure, acting tangentially to the perimeter of a transverse section
3.15
connection between the ends of pipes and/or fittings in which a gasket is used to effect a seal
3.16
length by which a pipeline progresses when an additional pipe is installed
Note 1 to entry: For socket and spigot pipes, it is equal to the total length of the pipe, Ltot, minus the maximum spigot insertion depth, Li, as given by the manufacturer and as shown in Figure 4. For flanged pipes, it is equal to the total length of the pipe.
Note 2 to entry: It is expressed in metres.
3.17
maximum allowable operating pressure
maximum internal pressure, including surge, which a component can safely withstand in service
3.18
mechanical flexible joint
flexible joint in which sealing is obtained by applying pressure to the gasket by mechanical means
3.19
numerical designation, which is a convenient rounded number, used for reference purposes
Note 1 to entry: All components of the same nominal size, DN, designated by the same PN number have compatible mating dimensions.
Note 2 to entry: Adapted from ISO 7268.
3.20
alphanumeric designation of size for components of a pipework system, which is used for reference purposes
Note 1 to entry: It comprises the letters DN followed by a dimensionless whole number, which is indirectly related to the physical size, in millimetres, of the bore or outside diameter of the end connections.
Note 2 to entry: Adapted from ISO 6708:1995, definition 2.1.
3.21
out-of-roundness of a pipe section, equal to Equation (1)
where |
|---|
| A1 |
is the maximum axis, in millimetres; |
| A2 |
is the minimum axis, in millimetres. |
|
3.22
casting of uniform bore, with straight axis, having either socket, spigot or flanged ends
Note 1 to entry: This does not apply to flanged sockets, flanged spigots and collars, which are classified as fittings.
3.23
flexible joint assembled by pushing the spigot through the gasket into the socket of the mating component
3.24
joint in which a means is provided to prevent separation of the assembled joint
3.25
female end of a pipe or fitting to make the connection with the spigot of the next component
3.26
male end of a pipe or fitting
3.27
maximum insertion depth of the spigot, Li, plus 50 mm
3.28
length of pipe barrel and fitting body or branch as defined in this International Standard
Note 1 to entry: For socket and spigot pipes, and fittings, it is designated Lu (lu for branches). For flanged pipes, and fittings, it is designated L (l for branches). See Figures 4 to 27.
Note 2 to entry: For flanged pipes and fittings, the standardized length L (l for branches) is equal to the total length. For socketed pipes and fittings, the standardized length Lu (lu for branches) is equal to the total length minus the spigot insertion depth, as indicated in the manufacturer’s catalogues.
3.29
proof-of-design test, which is done once and is repeated only after change of design
ICS 77.140.75; 91.140.40; 91.140.60
Price based on 73 pages
© ISO 2009 — All rights reserved