ISO 2531:1979

International Standard 2531
INTERNATIONAL ORGANIZATION FOR STANDARDIZATlON.MEXAYHAPOLIHAR OPTAHHJAUHR flO CTAHLIAFTH3AUHH.ORGANlSATlON INTERNATIONALE DE NORMALISATION
Ductile iron pipes, fittings and accessories for pressure
.-.
pipe-lines
.-*
Tuyaux, raccords er pièces accessoires en fonte ductile pour canallsations avec pression
Second edition - 1979-Os-01
UDC 621.643.22 Ref. No. IS0 2531-1979 (E)
Descriptors : iron and steel products, pipes (tubes), fittings, pressure pipes, accessories, spheroidal graphite cast iron, specifications,
tests, tension tests, flanges, dimensions, tolerances (mechanical), marking.
Price based on 36 pages
?-
FOREWORD
IS0 (the International Organization for Standardization) is a worldwide federation
of national standards institutes (IS0 member bodies). The work of developing
International Standards is carried out through IS0 technical committees. Every
member body interested in a subject for which a technical committee has been set
up 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.
Draft International Standards adopted by the technical committees are circulated
to the member bodies foL approval before their acceptance as International
Standards by the IS0 Council.
International Standard IS0 2531 was developed by Technical Committee ISO/TC 5,
Metalpipesand fittings. It has been approved by the member bodies of the following
countries :
Austria India South Africa, Rep. of
Canada Israel
Spain
Czechoslovakia Italy Switzerland
Denmark Japan Turkey
Egypt, Arab Rep. of Korea, Rep. of United Kingdom
Finland Mexico
USA
France Netherlands
USSR
Germany, F. R. Poland
Yugoslavia
Hungary Romania
The member bodies of the following countries expressed disapproval of the
document on technical grounds :
Australia
Belgium
This second edition cancels and replaces the first edition (i.e. IS0 2531-1974). It
also incorporates draft addenda 1, 2 and 3, approved by member bodies in 1978
but not published.
@ International Organization for Standardization, 1979
Printed in Switzerland
II
CONTENTS
Page
SECTION ONE : GENERAL SPECIFICATION
O Introduction . . 1
1 Scope and field of application .
..... 1
k
2 References . . 1
3 Types of joints .
..... 2
4 Thickness of pipes and fittings . . 2
5 Marking . . 2
6 Processing of the iron . . 2
7 Quality of pipes. fittings and accessories . . 2
8 Tolerances on joints . . 2
9 Tolerances on thickness . . 3
10 Manufacturing lengths and tolerances on length . . 3
11 Tolerances on the straightness of centrifugally cast pipes . . 3
12 Tolerances on masses . . 3
..... 4
13 Tensile tests - Test bars .
..... 4
14 Tensile tests - Method and results .
..... 5
15 Brinell hardness test .
16 Maximum working pressure and internal pressure proof test . 5
17 Coating . . 5
18 Inspection . . 6
SECTION TWO : SPIGOT AND SOCKET PIPES
....................
19 General . Pipes 6
20 Dimensions and masses . 7
SECTION THREE : FLANGES
21 General . Flanges . 8
22 Dimensions and drilling details of PN 10 flanges . 9
23 Dimensions and drilling details of PN 16 flanges . 11
24 Dimensions and drilling details of PN 25 flanges . 13
25 Dimensions and drilling details of PN 40 flanges . 15
...
III
SECTION FOUR . FITTINGS Page
............ 16
26 General . Fittings .
............ 18
27 Flanged socket .
............ 19
28 Flanged spigot .
............ 19
29 Collar .
............ 20
30 Double-socket 114 bend .
............ 20
31 Double-socket 118 bend .
............ 21
32 Double-socket 1/16 bend .
............ 21
33 Double-socket 1/32 bend .
........... 22
34 Double-socket tee with flanged branch
........... 26
35 All-socket tee .
............ 27
36 Double-socket taper .
........... 28
37 Double-flanged taper .
............ 28
38 Blank flange PN 10 . _ .
............ 29
39 Blank flange PN 16 .
............ 29
40 Blank flange PN 25 .
............ 30
41 Blank flange PN 40 .
............ 30
42 Reducing flange PN 10 .
............ 31
43 Reducing flange PN 16 .
............ 31
44 Reducingflange PN 25 .
............ 32
45 Double-flanged 114 bend .
............ 32
46 Double-flanged 114 duckfoot bend .
............ 33
47 Double-flanged 118 bend .
............ 34
48 All-flanged tee .
iv
INTERNATIONAL STANDARD IS0 2531-1979 (E)
Ductile iron pipes, fittings and accessories for pressure
pipe-lines
SECTION ONE
G EN ERA L SPEC I F I CAT 1 ON
O INTRODUCTION 1 SCOPE AND FIELD OF APPLICATION
This International Standard comprises a general
Ductile iron, also called nodular iron or spheroidal graphite
iron, is characterized by the presence, in the resultant specification completed by specific requirements applicable
castings, of spheroidal graphite in a quantity sufficient to to :
give the iron of these castings the mechanical characteristics
a) ductile iron pipes manufactured by any one of the
defined in this International Standard.
following four processes :
The high mechanical characteristics of ductile iron make it
1) centrifugal casting in lined or unlined metal
possible to manufacture pipes and fittings having adequate
moulds;
strength for all uses.
2) centrifugal casting in sand’) moulds;
Various methods of strengthening are authorized, however,
3) casting in sand’) moulds;
particularly where high working pressures have to be
applied to fittings having a large diameter branch, in which
4) casting in metal moulds.
the resulting stress in the metal may be too high.
b) ductile iron fittings and accessories manufactured by
Ductile iron differs from grey iron by its greater tensile
either of the following two processes:
strength and by its significant proof stress and elongation
1) casting in sand’) moulds;
after fracture. Tensile tests on machined specimens permit
the measurement of these different characteristics. It is for
2) casting in metal moulds.
this reason, using values compatible with the different
manufacturing processes, that this test is now in general
It is applicable to pipes, fittings and accessories for pressure
use for all pipes, fittings and accessories for ductile iron
pipe-lines for water, other liquids, or gas.
pipe4 ines.
The range of diameters extends from nominal diameter
DN 40 to nominal diameter DN 2000 inclusive. The
The value adopted for the density of ductile iron is
diameter DN 60 shown in parentheses in the tables exists in
7050 kg/m3. This value is a compromise between the
national standards in certain countries. However, it is
values measured in various manufacturing countries and
recommended that whenever possible it be replaced by the
provides a reasonably acceptable agreement between the
diameter DN 65.
calculated masses and actual masses.
The requirements of IS0 13 concerning the quality of
2 REFERENCES
the cast iron have been adapted to ductile iron and defined
more accurately as far as both the origin of the metal and
IS0 13, Grey iron pipes, special castings and grey iron
its characteristics are concerned, but leaving it to the
parts for pressure main lines.
manufacturers to choose from the various methods of
ISO/R 79, Brinell hardness test for steel, Amendment 1.
processing the molten metal.
1) By sand is to be understood sand or mineral-based materials used in the foundry trade irrespective of the type of bonding agent used.
IS0 2531 -1979 (E)
3 TYPES OF JOINTS 5 MARKING
The pipes and fittings may be supplied with various types Each pipe, fitting or accessory shall bear the mark of the
manufacturer, an indication that the casting is of ductile
of joint.
iron, and an indication of its nominal diameter. If
The specification mainly concerns pipes, fittings with
necessary, each fitting shall bear an indication of its main
sockets for elastomer gasket joints and flanged fittings.
characteristics. Pipes, fittings and accessories with a
nominal diameter greater than DN 300 shall also bear
It may also be used for pipes and fittings having other types
the year of manufacture.
of joint - for example lead caulked joints, which are still
used in certain countries. Castings with these various joints
The marks may be cast on, painted or cold stamped.
retain the same overall dimensions, making it easier for
manufacturers to use interchangeable patterns.
6 PROCESSING OF THE IRON
NOTE - The standard external diameter of the spigot end of pipes
and fittings remains the same for all types of joint. Furthermore,
The iron to be used for the casting of pipes, fittings and
this external diameter is the same as that of the spigot end of grey
iron castings (IS0 13). which makes it easier to joint the new accessories shall be prepared, at the choice of the
ductile iron pipes or fittings to existing grey iron pipe-lines.
manufacturer, in a cupola, an active mixer or any other
suitable metallurgical apparatus, and shall be made, as the
case may be, from pig iron or molten iron, iron or steel
4 THICKNESS OF PIPES AND FITTINGS
scrap, with such ferro-alloy and other additives as shall be
necessary because of the manufacturing process to produce
The standard thickness of pipes and fittings is calculated as
a ductile iron complying with the
in the resultant castings
a function of their nominal qameter by the formula :
requirements of this International Standard.
e = K (0,5 + 0,001 DN)
where
7 QUALITY OF PIPES, FITTINGS AND ACCESSORIES
e is the standard wall thickness, in millimetres;
After casting, ductile iron pipes, fittings and accessories
DN is the nominal diameter;
may be subjected, when necessary, to a suitable heat
treatment in order to give them the required mechanical
K is the coefficient selected from a series of whole
characteristics.
numbers. . 8, 9, 10, 11, 12. . and as determined in
the specific requirements of sections two and four of
Pipes, fittings and accessories shall not have any defects
this International Standard :
likely to be detrimental to their use.
= 9 for the pipes in table 9,
K
Pipes, fittings and accessories showing small imperfections
inseparable from the method of manufacture and in no way
K = 12 for the fittings in tables 20 to 26,32,33 and
affecting their use, shall not be rejected. On his own
4 1 to 43,
responsibility, the manufacturer may remedy such slight
K= 14for the fittings in tables27 to31 and 44 to46.
surface imperfections in a suitable manner.
If necessary, each particular specification shall give an
With the previous agreement of the purchaser or his
additional formula applicable to small-diameter castings.
representative, certain defects may be repaired by any
proven process such as welding. In such cases, the purchaser
The external diameter of the pipes, expressed in milli-
may require one of the tests described below to be carried
metres, is fixed as a function of the nominal diameter
out.
and independently of the pipe wall thickness. Increases or
decreases in the pipe wall thickness shall be obtained by
The pipes should be such that they can be cut, drilled or
modification of the actual internal diameter.
machined; in case of dispute they shall be considered as
acceptable provided that the superficial hardness does not
The wall thickness of the fittings may be adjusted to the
exceed 230 HB. The superficial hardness of fittings and
forces acting in each point of the casting, particularly to the
accessories shall not exceed 250 HB.
mechanical stresses induced by internal pressure. In bends,
for example, the wall thickness at the inner radius may be
greater than that at the outer radius.
8 TOLERANCES ON JOINTS
Increases or decreases in the wall thickness of fittings may
The tolerances on joints depend on the characteristics
be obtained by modifications to either the internal or the
peculiar to each type of joint, and shall be specified in the
external diameter of the fittings.
national standards, or, when not so specified, in the manu-
facturers' catalogues for the type of joint and the nominal
e indicated in each table and on the drawings
The thickness
diameter considered.
of the fittings shall be a mean thickness corresponding to
the mass of each casting. The actual thickness at any
NOTE - As a general rule, the tolerances on the sockets are more
particular point may be varied to meet local stresses,
restricted than the tolerances on the barrel because of the greater
depending on the shape of the fitting. thickness and the greater rigidity of the sockets.
IS0 2531 -1979 (E)
specified, the allowed reduction in length being given in
9 TOLERANCES ON THICKNESS
table 3.
The tolerances on wall thickness and flange thickness are as
given in table 1, where
TABLE 3
Dimensions in metres
b is the standard thickness of the flange, in millimetres;
I Specified length 1 Reduction in length I
DN is the nominal diameter.
TABLE 1
over 4
Tolerance
Type of casting Dimension
The tolerances on the standard manufacturing lengths of
pipes are indicated in section two.
Pipes centrifugally
Wall thickness - (1.3 + o.001 DN)')
cast in sand or
Flange thickness (2 + 0,056)
metal moulds
10.2 Fittings
metal moulds The standard manufacturing lengths of fittings and the
e.
permitted tolerances on these lengths are indicated in
Fittings and Wall thickness - (2,3 + 0,001 DN)')
section four.
1 ) No limit for the plus tolerance has been set (see note to clause 12).
11 TOLERANCES ON THE STRAIGHTNESS OF
CENTRIFUGALLY CAST PIPES
When the pipes are rolled along two gantries separated by
approximately two-thirds of the length L of the pipe to be
10 MANUFACTURING LENGTHS AND TOLERANCES
checked, the maximum deviation f,, in millimetres, shall
ON LENGTH
not be greater than 1,25 times the length L, in metres, of
The tolerances on length for the pipes and fittings take into
this pipe, i.e. :
account variations due to shrinkage and growth, depending
fm < 1.25 L
on the composition and heat treatment of the ductile iron.
These tolerance limits have been generously chosen to make
it possible, by using interchangeable patterns, to
manufacture castings which may have slightly different
working lengths, depending on the type of joint with which
12 TOLERANCES ON MASSES
they are provided.
The values of the masses of the sockets appearing in the
tables of this International Standard are approximate.
The masses of pipes and fittings corresponding to each type
of joint shall be specified in the national standards or, when
10.1 Spigot and socket pipes
not so specified, in the manufacturers' catalogues; these
shall have been calculated by taking the density of cast
The standard manufacturing lengths of spigot and socket
pipes are as shown in table 2. iron as 7 050 kg/m3.
The mass of the pipes for each working length, and the
mass of the fittings shown in the tables have been
calculated taking into account in each case a socket mass
fixed by a linear formula corresponding to average socket
Nominal diameters Standard lengths
as manufactured in practice in various countries.
masses
DN m
The values indicated for the mass per metre of pipe and the
40 to 65
2 - 3 -4 - 5 - 5.5 - G
0,l kg.
masses of the sockets are rounded off to the nearest
80 to 500
4 -5-5.5 -6
The values indicated for the masses of accessories are
600 to 1000
4 - 5 - 5.5 - 6 - 7
rounded off
1200 to 2000 6-7-8-9
- to the nearest 0.1 kg for masses less than 20 kg;
- to the nearest 0.5 kg for masses between 20 and
Of the total number of spigot and socket pipes to be
100 kg;
supplied in each diameter, the manufacturer may supply up
- to the nearest kilogram for masses above 100 kg
to 10 % in lengths shorter than the standard lengths
IS0 2531 -1979 (E)
The tolerances on the standard masses are given in table 4. the sample and the diameter of the bar are given in table 6,
dependent on the mean thickness of the casting.
TABLE 4
Tolerance
in standard
Type of casting
mass
Mean thickness Thickness Diameter
%
of sample of test bar
of casting
8 I
up to DN 200 inclusive 18
Pipes centrifugally cast
less than 12 6
above DN 200 *5
12 or above
Pipes cast in sand or metal moulds
Standard fittings except as stated below
The gauge length of the machined bar shall be equal to five
times its diameter.
Bends, fittings with branches, and non-standard
? 12
fittings
In all cases, the ends of the test bars shall be such that they
NOTE -Castings of a greater mass than the maximum will fit the testing machine.
shall be
accepted provided that they comply in every other respect with the
requirements of this International Standard.
TENSILE TESTS - METHOD AND RESULTS
The manufacturer's mechanical tests shall be carried out
during manufacture.
13 TENSILE TESTS - TECT BARS
The mechanical acceptance tests shall be carried out on
castings grouped in batches as follows :
Pipes centrifugally cast in sand or metal moulds
13.1
a) Pipes centrifugally cast in sand or metal moulds
The machined test bar for the tensile test shall be taken
from the spigot end of the pipe, at approximately
Each batch shall be made up of pipes cast successively as
mid-thickness of the wall, and its axis shall be parallel to
follows :
the axis of the pipe.
- DN 40 to 300 : 100 pipes
- DN 350 to 600: 50pipes
The test bar shall include a cylindrical part, the gauge
length of which shall be equal to five times its diameter; the
- DN 700 to 1000 : 25pipes
latter shall be as given in table 5, according to the thickness
of the pipe.
- DN 1200 to 2000 : 10 pipes
b) Pipes, fittings and accessories cast in sand or metal
TABLE 5
Dimensions in millimetres moulds
Castings made from iron of substantially the same
Diameter of
Thickness of pipe
composition and, if necessary, having been subjected to
test bar
shall be considered as one
the same heat treatment,
batch. The size of such batches shall be limited to
less than 5
4 tonnes of crude castings, excluding the mass of the
5 and above, but below 6
risers.
6 and above, but below 7
7 and above, but below 8
For one pipe, or from one sample of each batch in the case
8 and above, but below 10
of fittings and accessories, the manufacturer shall take one
10 and above, but below 12
test bar, which shall satisfy the requirements of table 7.
12 and above
If the results of this test are below the specified minimum
values, two other test bars shall be taken from the same
pipe, or from the same sample in the case of fittings and
accessories, and these shall satisfy the same specified
13.2 Pipes, fittings and accessories cast in sand or metal requirements.
moulds
Pipes from which test bars have been cut shall be accepted
The machined bar for the tensile test shall be taken from a by the purchaser as complete lengths.
sample cast separately, but from the same iron as that used
NOTE - The provisions made for dividing the pipes and fittings into
for the castings, and, if necessary, having been subjected to
batches and for the heat treatment of the castings, together with the
the same heat treatment. The choice of the method used
of a test bar according to the
specifying of different diameters
for casting the sample shall be left to the manufacturer with
thickness and type of the casting, contribute towards the accuracy
a view to obtaining soundly cast test bars. The thickness of
of this test.
IS0 2531 -1979 (E)
1) The proof stress shall be measured only upon special agreement and under conditions which shall be specified in the order
15 BRINELL HARDNESS TEST The actual test pressures shall not exceed the following
values :
The Brinell hardness, HB, specified in clause 7, shall be
- DN 40to 300:p= 100bar
checked by means of a test carried out on the outer surface
of the castings after slightgrinding.
- DN 350to 600 :p= 80 bar
The Brinell hardness test shall be carried out in accordance
- DN 700 to 1000 : p = 60 bar
with ISO/R 79, Amendment 1, with a steel ball of 10 mm
or 5 mm diameter.
- DN 1200 to 2000 : p = 40 bar
16 MAXIMUM WORKING PRESSURE AND INTERNAL
16.2.2 Fittings
PRESSURE PROOF TEST
Fittings shall be subjected to a leak-tightness test carried
out with water or air, under the conditions indicated by the
16.1 Maximum working pressure
relevant specific requirements.
The maximum working pressures for these pipes, fittings
NOTE - Because of their great mechanical strength, ductile iron
and accessories shall be determined according to the
pipes and fittings may be used for a very wide range of working
regulations in operation in each country as a function of
conditions. The hydrostatic test or leak-tightness test pressures are
indicated, therefore, in the specific requirements applicable to each
the works proof test pressure and the anticipated working
type of casting. For gas pipes, special tests may be required.
conditions : type of liquid transported, static and transitory
overloads, etc.
I,
16.2 Internal pressure proof test
17 COATING
Except when otherwise specified, all pipes, fittings and
16.2.1 Spigot and socket pipes
accessories shall be coated inside and outside.
Pipes shall be subjected to a works hydrostatic test for a
The coating shall dry rapidly with good adherence, and
duration of 15 s at a minimum pressure defined by the
shall not scale off.
corresponding spec if ic require men ts.
The inside coating shall not contain any constituent soluble
It is recommended that this pressure p, expressed in bars')
in water or any ingredient liable to impart any taste or
as a function of the coefficient K (clause 4), be calculated
smell to the water after suitable washing out of the mains.
using the following formulae :
For pipe-lines carrying potable water, or alimentary fluids,
the inside coating shall not contain any toxic constituent.
- DN 40to 300:~=0,5(K+l)~
NOTE - The requirements concerning the coating of the various
- DN 350to 600 p = 0,5 K2
castings are based on similar requirements in IS0 13 for grey iron
pipes and fittings. Technical specifications concerning cement
- DN 700to 1000 p = 0,5 (K - 112
mortar internal linings for pipes will be the subject of a separate
-
International Standard.
DN 1200 to 2000 : p = 0,5 (K - 212
1 bar = 0.1 MPa
1)
IS0 2531-1979 (E)
18 INSPECTION The inspection and weighing of the pipes, fittings and
accessories may be carried out after coating.
If the purchaser wishes to inspect the pipes, fittings and
accessories, such inspection shall be undertaken at the
works of the manufacturer. The equipment and labour
Should the purchaser or his representative not be present
necessary for the carrying out of the inspection shall be
when these operations are carried out at the time agreed
provided by the manufacturer.
upon, the manufacturer shall be entitled to proceed with
The inspector appointed by the purchaser and accredited to
the inspection without the purchaser or his representative
the manufacturer shall be advised previously of the time at
being present.
which the operations of inspection will normally take place.
The inspector may witness the sampling, the preparation
NOTE - The requirements concerning inspection of the various
and testing of the test pieces, the checking of dimensions
IS0 13 for grey iron
castings are based on similar requirements in
and masses, and the hydraulic tests. pipes and fittings.
SECTION TWO
SPIGOT AND SOCKET PIPES
19 GENERAL -PIPES However, for pipes DN 40 to 200, the thickness is given by
the additional formula
Section two of this International Standard defines (see
e = 5,8 + 0,003 DN
table 9) a range of ductile iron pipes which satisfy most of
the normal needs, particularly in the conveyance and
with a minimum of 6 mm for pipes DN 40 to 65.
distribution of water or gas under pressure.
In these formulae
The thickness of the pipes is defined as a fqnction of their
e is the standard wall thickness, in millimetres;
diameter by linear formulae, as given in IS0 13 for grey
iron pipes.
DN is the nominal diameter.
In case of particular needs, other pipe ranges, having smaller
The hydrostatic works test pressure for these pipes is shown
or greater wall thicknesses, could be envisaged.
in table 8.
TABLE 8
Table 9 deals with ductile iron spigot and socket pipes used
for the transportation and distribution of water or other
Nominal diameters Hydrostatic works test pressure
liquids, or gas under pressure. It applies equally to double
DN bar
spigot pipes.
40 to 300
Their thickness e has been calculated as a function of the
350 to WO
nominal diameter DN, by the formula given in clause4,
700 to 1000
using 9 as the value for K, thus
1200 to 2000
e = 4,5 + 0,009 DN
IS0 2531 -1979 (E)
20 DIMENSIONS AND MASSES
5,8 + 0,003 DN, with a minimum value of 6, for DN 40 to 65
Symbol :
5,8 + 0,003 DN for DN 80 to 200
e =
1 4.5 + 0,009 DN for DN 250 to 2000
Tolerance on L = f 30')
I BI
L
TABLE 9
Masses in kilograms
Dimensions in millimetres
*
Barrel Total mass (approximate) for one working length L of :
Socket
Nominal
Mass per mass
diameter
(approxi- 3m 4m 5m 6m 7m 8m 9m
metre 55 m
e
DE
DN
(approxi- mate)
mate)
-
- - - -
40 56 6 28
6.6 1,7
- - - -
50 66 6 8 34
2.1
-
54 59
(60) 77 6 40 49,5
9 -4 2.5
-
65 82 6 10.1 43 53 58.5 63.5
2,7
-
80 98 6 12.2 52 64,5 70.5 76.5
3.4
-
1 O0 118 15.1 64.5 80 87.5 95
6.1 4.3
-
125 144 18.9 81.5 1 O0 110 119
6.2 5.7
-
121 144
150 170 22.8 98.5 133
6,3 7.1
-
179 194
200 222 30,6 10.3 133 163
6.4
-
215 235 255
250 274 40.2 14.2 175
6.8
-
222 273 298 323
300 326 50.8 18.6
7.2
-
277 340 37 1 403
350 378 7.7 63,2 23.7
-
400 429 75.5 29.3 33 1 407 482
8,1
-
460 616 669
500 532 9 104.3 42.8 564
137.1 59.3 608 745 813 882 1 O19
600 635 9.9
700 10,8 173,9 79,l 775 94 9 1 036 1123 1 296
11,7 1179 1 286 1 394 1 609
800 84 2 215,2 102.6 963
1171 1431 1561 1691 1951
900 945 12,6 260,2 129,9
13.5 161.3 1 399 1708 1862 2 017 2 326
1 O00 1 048 309.3
- -
1200 15.3 420,l 237.7 2 548 2 758 3 178
- - -
3 563 4 110
1400 1462 17.1 547.2 279.3
- - -
1517 5 208
1600 1 668 18,9 690.3 375.4
-
- -
5 591 6 441
1800 1875 20.7 850.1 490.6
- - -
5 784
2000 2 082 22,5 1 026,3 626.4 7811
-
According to the type of joint, the difference between the working length f. and the working manufacturing length may reach 100 mm for
1)
DN 40 to 1000, and 250 mrn for DN 1200 to 2000.
IS0 2531-1979 (E)
SECTION THREE
FLANGES
21 GENERAL - FLANGES As specified in IS0 13, PN 10 flanges (see tables 11 and 12)
may be used on socket pipe-lines up to pressures of
In IS0 13, only one type of flange has been adopted for
approximately 15 bar.
grey iron pipe-lines. The increase in pressures permissible in
ductile iron pipe-lines, and the extension of the range of
uses to which they may be put, have led to the inclusion of
four types of flange corresponding to the nominal pressures
PN 10, PN 16, PN 25 and PN 40 respectively.
The flanges may have a machined raised face and drilled
holes; they may also be supplied as cast where particularly
Because they have identical drilling details, it has been
accurate moulding processes are used, while respecting the
possible to adopt a single design for flanges DN 40 and 50
dimensional requirements shown in one of the tables 11 to
for nominal pressures PN 10-16-25 and 40, and, for DN 60
18 hereafter for a selected nominal diameter and nominal
and 65, a common design for nominal pressures PN 10 and
pressure.
16 on the one hand and PN 25 and 40 on the other hand.
Moreover, since a degree of rationalization of flange
dimensions and/or drilling details already exists for DN 80
to 200, for the above nonTina1 pressures, and since this
It should be noted that the diameters of bolt holes of the
rationalization of flange dimensions has been extended to
various types of flange are 1 mm larger than those envisaged
include DN 250 and 300 for nominal pressures PN 10 and
for pipe-lines not laid in the ground. This increase makes it
PN 16, the multiplicity of designs has been reduced as
easier to assemble the castings, which is sometimes difficult
shown in table 10.
in the case of underground pipe-lines. It also permits the
TABLE 10
use of larger diameter bolts whenever this is justified by
considerations of resistance to corrosion.
Nominal Identical flange Identical drilling
for details for
diameters dimensions
nominal pressures nominal pressures
PN 10-16-25-40
40 and 50
The diameter of the holes has been fixed according to the
t 60 and 65 i PN 10-16/PN 25-40
diameter of the bolts in accordance with the following
PN 16-25 rule :
80 PN 10-16-25
PN 10-16 PN 10-16
I 100 to 150 I
for a bolt diameter < 52 : diameter of the bolt -i 4 mm;
200 to 300 PN 10-16
for a bolt diameter > 52 : diameter of the bolt -t 6 mm.

IS0 2531 -1979 (E)
22 DIMENSIONS AND DRILLING DETAILS OF PN 10 FLANGES
22.1 Dimensions TABLE 11
10 + 0,035 DN, with a minimum value of 16, for
Dimensions in millimetres Masses in kilograms
-
DN 40 to 300
Approxi-
b= 10 + 0,025 DN, with a minimum value of 20,5, for
mate
DN 350 to 1200
Nominal
flange
diameter D
a b C S
20 -t 0,015 DN for DN 1400 to 2000
mass
DN
(hatched
0,8 a for DN 40 to 600
part)
s= (
0.7 a for DN 700 to 2000
40 150 83 19 16 3 16
1.7
50 165 98 19 16 3
16 2.1
(60 ) 175 108 19 16 3
65 185 118 19 16 3
200 133 19 16 3 15 3
e
100 220
153 19 16 3 15
3,3
250 183 19 16 3 15 4
285 209 19 16 3 15
4,9
200 340 264 20 17 3 16
6.8
250 400 319 22 19 3 17.5
9,6
300 455 367 24.5 20,5 4 19.5 12,8
350 505 427 24.5 20.5 4 14.1
19.5
565 477 24.5 20.5 4 19.5
16.3
670 582 26.5 22.5 4 21 21.8
780 682 30 25 5 24 30.8
895 797 32.5 27.5 5 23
40.5
800 1015 904 35 30 5 24.5
54.8
900 1115
1 004 37.5 32.5 5 26.5
64,3
1 O00 1 230 1111 10
35 5 28 81,4
1200 1455 1 330 15 40 5
31,5 120.9
1400 1675 1 530 16 41 5 32 147.8
1600 1750 19 44 5 34.5 206.4
1800 2 115
1 950 52 47 5 36.5 236.3
2000 2 325
2 150 55 50 5 38,5 279.4
IS0 2531 -1979 (E)
22.2 Drilling details
DN 40 to 65 80 to 200 250 and 300
DN 350 and 400 500 and 600
TABLE 12
Dimensions in millimetres
Holes Bolts
Nominal
diameter
Number Diameter 3iameter
DN
D c d
40 150 110 4 19 16
50 165 125 4 19 16
DN 700and800
175 135 4 19 16
(60)
65 185 145 4 19 16
d
80 200 160 8’’ 19 16
1 O0 220 180 8 19 16
125 250 210 8 19 16
150 285 24 O 8 23 20
200 340 295 8 23 20
250 ’ 400 350 12 23 20
300 455 400 12 23 20
350 505 460 16 23 20
c I
l -1 400 565 515 16 28 24
500 670 620 20 28 24
600 780 725 20 31 27
DN 1200
1400 1600
700 895 840 24 31 27
\d
800 1015 24 34 30
900 1115 1 050 28 34 30
1000 1 230 1160 28 37 33
1200 1455 1380 32 40 36
1400 1675 43
1 590 36 39
1600 1915 1820 40 45
1800 2 115 2 020 44 49 45
2000 2 325 2 230 48 49 45
I 0
1) For flanges with nominal diameter DN 80 and nominal pressure
DN 1800
2000 PN 10, the number of holes may be reduced to 4 at the purchaser‘s
request, in order to permit coupling with an existing flange of an old
, “t--
, \)4,cI
pipe-line.
IS0 2531 -1979 (E)
23 DIMENSIONS AND DRILLING DETAILS OF PN 16 FLANGES
TABLE 13
23.1 Dimensions
10 + 0,035 DN, with a minimum value of 16, for Masses in kilograms
Dimensions in millimetres
DN 40 to 1200
b =
Approxi-
20 + 0,025 DN for DN 1400 to 2000
mate
Nominal
flange
0.8 a for DN 40 to 600
D a b C 5
diameter
mass
DN
0.7 a for DN 700 to 2000
(hatched
parti
150 83 19 16 3 16
40 1.7
50 165 98 19 16 3 16
2.1
175 108 19 16 3 16
(60) 22
65 185 118 19 16 3 16 2.5
200 133 19 16 3 15
80 2.9
220 153 19 16 3 15
1 O0 3,3
c
125 250 183 19 16 3 15
1 50 285 209 19 16 3 15
4.9
200 34 O 264 20 3 16 6,6
3 17.5
250 400 319 22 19 92
24.5 20.5 4 19.5 12.4
300 455 367
432 26.5 22.5 4 21 17.2
350 520
a
484 28 24 4 22.5 21,9
400 580
715 606 31.5 27.5 4 25 37
840 721 36 31 5 29 57,3
910 791 39,5 34,5 5 27,5 55.6
43 38 5 30 74
800 1025 898
46.5 41.5 5 32.5 88.2
900 1125 998
1115 50 45 5 35 122,9
1 O00 1255
5 40 185.2
1200 1485 1 330 57 52
60 55 5 42 21 5,9
1400 1685 1530
1750 65 60 5 45.5 308.4
1600 1 930
1950 70 65 5 49 362.2
1800 2 130
2 150 75 70 5 52.5 432,2
2000 2 345
- - - -
-
IS0 2531 -1979 (E)
23.2 Drilling details
DN
40 to 65 80 to 150 200 to 300
b
-
500 and 600
350 and 400
DN
TABLE 14
Dimensions in millimetres
Holes
Bolts
Nominal
diameter
Number
Diameter liameter
DN
D C
d-
700 and 800 900 and 1000
DN
40 150 110 4 19 16
1-d
. I "
50 165 125 4 19 16
(60) 175 135 4 19 16
65 185 145 4 19 16
80 200 160 8 19 16
1 O0
220 180 8 19 16
125 250 210 8 19 16
150 285
240 8 23 20
200 340
295 12 23 20
250 400 12 24
355 28
c
-II II I
300 455 410 12 28 24
D 1- A
- ci
350 520 470 16 28 24
D I
-I
400 580 525 16 31 27
DN 1200 1400 1600 .
500 650 34 30
715 20
600 840 770 20 37 33
700 910 840 24 37 33
800 1025 950 24 40 36
900 1125 1 050 28 40 36
1 O00 1 255 28 43 39
1200 1485 1390 32 49 45
1400 1685
1 590 36 49 45
1600 1930 1820 40
56 52
1800 2 130 2 020 44
56 52
2000 2 345 2 230 48 62
DN 1800 2000
I
-
I-
IS0 2531 -1979 (E)
24 DIMENSIONS AND DRILLING DETAILS OF PN 25 FLANGES
TABLE 15
24.1 Dimensions
10 + 0,045 DN, with a minimum value of 16, for
Dimensions in millimetres Masses in kilograms
- - -
DN 40 to 1200
b =
Approxi-
I 20 + 0,035 DN for DN 1400 to 2000
mate
Nominal
flange
0,8 a for DN 40 to 600
diameter D a b C S
s= (
mess
DN
0.7 a for DN 700 to 2000
(hatched
part)
- -
40 150 83 19 3 16
16 1.7
50 165 98 19 3 16
16 2.1
(60) 175 108 19 16 3 16
2.1
65 118 19 16 3 16
185 2.4
80 200 133 19 16 3 15
1 O0 235 159 19 16 3 15
3.8
c
125 270 184 19 16 3 15
4.6
150 300 214 20 17 3 16
5.9
200 360 274 22 19 3 17.5
8.7
250 425 33 1 24.5 21,s 3 19.5 13.1
300 485 389 27.5 23,5 22 18
350 555 446 30 26 4 24 25.5
-1
400 503 32 33,2
620 28 4 25.5
500 730 61 3 36.5 4 48.7
32,5 29
I
600 845 718 42 37 5 33.5 71.5
700 960 820 46.5 41,s 5 32.5 90.3
800 1085 929 51 46 5 35.5 123,2
900 1185 1029 55.5 50.5 5 39 148.6
1 O00 1320 1142 60 55 5 42 200.7
1200 1 530 1350 69 64 5 284.7
48,5
1400 1 755 1 560 74 5 52 368.1
1 780 5 485,5
1600 1975 81 76 56,5
1800 5
2 195 1985 88 83 61.5 601.9
2000 2 210 784.9
2 425 95 90 5 66.5
- - - - -
-
IS0 2531 -1979 (E)
24.2 Drilling details
DN 40 and 50 60 and 65 80 to 150 200 and 250
d
O
500 and 600
DN 300 to 400
TABLE 16
Dimensions in millimetres
Holes
Bolts
Nominal
diameter
Number
Diameter Diameter
DN
D C d
- - ~-
700 and 800
DN 900 and 1000
40 150 110 4
19 16
, -4 125 4 19
50 165 16
(60) 175 135 8 19 16
65 185 145 8 19 16
80 200 160 8 19 16
1 O0 235 190 8 23 20
125 270 220 8 28 24
150 300 250 8 28 24
200 360 310 12 28 24
250 425 370 12 31 27
300 485 430 16 31 27
555 490 16 34 30
4 D 4
400 16 33
620 550 37
DN 1200 1400 1600 500 730 660 20 37 33
600 845 770 20 40 36
\!
700 24
960 875 43 39
800 1085 990 24 49 45
900 1185 1 O90 28 49 45
1 O00 1320 1210 28 56 52
1200 1 530 1420 32 56 52
1400 1755 1640 36 62 56
1600 1975 1860 40 62 56
1800 2 195 2 070 44 JO 64
2000 2 425 2 300 48 70 64
DN 1800
IS0 2531 -1979 (E)
25 DIMENSIONS AND DRILLING DETAILS OF PN 40 FLANGES
25.2 Drilling details
'10 i- 0,045 DN, with a minimum value of 16, for
DN 40 to 100
b=
1 O + 0,085 DN for DN 125 to 400
20 4- 0,055 DN for DN 500 and 600
DN 40 and 50 60 and 65 80 to 150 200 and 250
t
~-
DN 300 to 400 500 and 600
LL-L
I- D
TABLE 17
Masses in kilograms TABLE 18
Dimensions in millimetres
-
9pproxi- Dimensions in millimetres
mate
Nominal
flange Holes Bolts
D a b C S Nominal
diameter
mass
diameter
DN
(hatched Number Diameter Diameter
DN
D C
d
parti
-
16 3 16 40 150 110 4 19 16
40 150 83 19 1.7
3 50 165 125 4 19 16
50 165 98 19 16 16 2.1
(60) 175 135 8 19 16
(60 1 175 108 19 16 3 16 2,1
185 145 16
3 65 8 19
65 185 118 19 16 16 2.4
80 200 160 8 19 16
133 19 16 3 15
80 200 2.9
100 235 190 8 23 20
1 O0 235 159 19 16 3 15
3 -8
270 24
125 220 8 28
125 270 184 23.5 20,5 3 16.5
5.9
150 300 250 8 28 24
150 300 214 26 23 3 18 8
200 375 320 12 31 27
27 3 21 14
200 375 28 1 30
250 450 385 12 34 30
343 34.5 31.5 3 24 23.2
250 450
300 515 450 16 34 30
406 39,5 35.5 4 27.5 33.5
300 515
350 580 510 16 37 33
350 580 463 44 40 4 31 46.7
400 660 585 16 40 36
400 660 535 48 44 4 33.5 66.9
500 755 670 20 43 39
500 755 61 7 52 48 4 36.5 82,3
890 45
124.1 600 795 20 49
600 890 734 58 53 5 40.5
- -
- - - -
IS0 2531-1979 (E)
SECTION FOUR
FITTINGS
of double-socket tees with flanged branches (see tables 27
26 GENERAL - FITTINGS
all diameters smaller than and equal to the
to 30) specifies
In general, the ductile iron fittings are of designs similar to nominal diameter of the body of the tee, with the
those of grey iron fittings (see IS0 13) and their ends are exception of DN 125, which is in less common use; the
flanged or, preferably, socketed.' range of the branches of all-flanged tees (see tables 44 to 46)
is substantially the same; that of all-socket tees (see
The greater mechanical strength of ductile iron has made it
table 31) is limited to the most common smaller nominal
possible to improve the design of fittings and to reduce
diameters i.e. : DN 80, 100 and 150, and to the nominal
their dimensions. This makes it easier to lay mains in
diameter of the body of the tee.
congested urban areas of large towns, and results in a
reduction in the size of valve chambers, the dimensions of Above DN 200, only tees with flanged branches are
which depend mainly on the space occupied by the fittings.
specified, the range of these branches including all the
principal diameters up to the diameter of the body.
The flange-socket pieces (see table 20) and the straight
collars (see table 22) have an internal diameter enlarged
The range of tees with flanged branch specifies, for all the
sufficiently to allow the adjacent pipes to slide through,
diameters, the branch with DN 600 corresponding to the
facilitating the dismantling and the longitudinal adjustment
"manhole" and only specifies branches with a nominal
of the pipe-line sections. -
diameter greater than DN 1000 where the cross-section is
close to half that of the body.
The double socket bends (see tables 23 to 26) have lengths
increasing in proportion to their angle of deviation, their The connection of a pipe-line of another diameter with
bearing surface on the thrust blocks thus being adjusted to these tees is achieved through a double-flanged taper (see
the size of the lateral forces which they exert on these table 33) or a reducing flange (see tables 38 to 40).
thrust blocks.
Double-socket tapers (see table 32). used mainly for a
The introduction of reducing flanges (see tables 38 to 40) reduction in diameter, have the shortest practicable lengths.
has made it possible to simplify the range of flanged-branch
Double-flanged tapers (see table 331, generally placed
tees (see tables 27 to 30 and 44 to 46); the use of a
between two successive diameters, have a length in
combination of these fittings makes it possible to provide
proportion to the variation in diameter, each side being
users with the greatest number of possibilities with the
sloped at 5' to the centre line, and chosen so as to reduce
smallest number of types of castings.
the pressure loss when the tapers are used to increase the
diameter.
The effect of this arrangement, based on market statistics,
is to reduce stores both at the manufacturer's works and at
Table 20 and those following are for ductile iron fittings
the customers' premises and also to make supply easier.
for pressure pipe-lines for the transportation and distri-
Up to and including DN 200, the range of the branches
bution of water or other liquids, or gas under pressure.
1) This preference for fittings with sockets is justified by many advantages, defined below :
In a main, the position of the fittings - bends, tees, etc. - is nearly always governed by the layout of the pipe-line and rarely coincides with the
end of a pipe.
It is generally necessary to insert, between the last standard-length pipe and the fitting, a shorter section obtained by cutting a standard-length
pipe into two pieces. The first piece is used before the fitting and the second immediately after, one of these pieces being without a socket. The
double-socket fittings provide the pipe-line with the additional socket which would otherwise be missing and, because of this, it is not necessary
to abandon certain lengths of docblespigot pipe on the site.
Double-socket fittings, as compared with the other fittings, have the following advantages :
- mechanical strength increased by the presence at each of their ends of a very strong socket;
- excellent stability on thrust-blocks which can extend over the whole length of the fittings;
- complete accessibility of joints which are clear of thrust blocks;
- simplification of orders and of the supply of spares by the elimination of numerous duplicating types of fittings;
- facility of moulding on symmetrical pattern plates giving good conditions of accuracy and productivity.

IS0 2531 -1979 (E)
The thickness of fittings has been calculated as a function tightness test carried out either with air at a pressure of
of the nominal diameter DN by using the formula in 1 bar or with water at the pressure indicated in table 19.
clause 4, with the following values for K :
TABLE 19
K = 14 for tees, thus e = 7 + 0,014 DN
Hydrostatic leak-tightness test
K = 12 for other fittings, thus e = 6 + 0,012 DN
1 NominaF:meters
pressure
bar
For DN 40 to 65, the thickness of the fittings has been
limited to 7 mm, so that, taking the tolerances into
40 to 300
account, the thickness of the fittings is always at least equal
350 to ô00
to that of the pipes of the same nominal diameter.
700 to 2000
I
The fittings shall be submitted at the works to a leak-
.
IS0 2531-1979 (E)
27 FLANGED SOCKET
12 (0,5 + 0,001 DN), with a minimum value of 7, for
e= DN40to65
12 (0,5 + 0,001 DN) for DN 80 to 2000
I
25 + 1 ,O5 DN for DN 40 to 1200
Symbol :
d=(
30 +1,0333 DN for DN 1400 to 2000
120 + 0,l DN (rounded off to I 5) for DN 40 to 1200
Fi
L =
170 + 0.1 DN (rounded off to f 5) for DN 1400 to
I2000
f 25 for DN 40 to 1200
Tolerances on L =
c f 35 for DN 1400 to 2000
*
TABLE 20
Masses in kilograms
Dimensions in millimetres
Nominal
MIIS (approximate) with flange :
d L
diameter e
PN 25 PN 40
PN 10 PN 16
DN
7 67 125
40 4.5 4.5 4.5
7 125
50 78 5,4 5.4 5.4
7 125
(60) 88 6,O 6,O 5.9
7 125
65 93 6.4 64 6.3
7 130
80 1 O9 J .5 J .4 J .3
130 130 9 9
1 O0 7.2 9.5
12,l
156 135 11.5 11,5
125 7.5
15.2
150 183 135 14.2 14.2
J .8
20 22
200 235 140 20.5
8.4
27.5 31.5
250 9 288 145 28
340 150 37 36.5 42
300 9.6
...