SIST EN ISO 3126:2005

SLOVENSKI STANDARD
SIST EN ISO 3126:2005
01-julij-2005
Cevni sistemi iz polimernih materialov - Sestavni deli iz polimernih materialov –
Ugotavljanje mer (ISO 3126:2005)
Plastics piping systems - Plastics components - Determination of dimensions (ISO
3126:2005)
Kunststoff-Rorhleitungssysteme - Rohrleitungsteile aus Kunststoffen - Bestimmung der
Maße (ISO 3126:2005)
Systemes de canalisations plastiques - Composants en plastiques - Détermination des
dimensions (ISO 3126:2005)
Ta slovenski standard je istoveten z: EN ISO 3126:2005
ICS:
23.040.20 Cevi iz polimernih materialov Plastics pipes
SIST EN ISO 3126:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 3126:2005

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SIST EN ISO 3126:2005



EUROPEAN STANDARD
EN ISO 3126

NORME EUROPÉENNE

EUROPÄISCHE NORM
March 2005
ICS 23.040.20; 23.040.45
English version
Plastics piping systems - Plastics components - Determination
of dimensions (ISO 3126:2005)
Systèmes de canalisations plastiques - Composants en Kunststoff-Rorhleitungssysteme - Rohrleitungsteile aus
plastiques - Détermination des dimensions (ISO Kunststoffen - Bestimmung der Maße (ISO 3126:2005)
3126:2005)
This European Standard was approved by CEN on 21 February 2003.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Central Secretariat or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official
versions.

CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.




EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 3126:2005: E
worldwide for CEN national Members.

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SIST EN ISO 3126:2005
EN ISO 3126:2005 (E)
Contents           page
Foreword.3
1 Scope.4
2 Normative references .4
3 Terms, definitions and symbols .4
3.1 Terms and definitions.4
3.2 Symbols .4
4 Measuring devices .5
4.1 General requirements .5
4.2 Instruments .6
5 Determination of dimensions.6
5.1 General .6
5.2 Wall thicknesses .7
5.3 Diameters.8
5.4 Out-of-roundness .9
5.5 Pipe lengths .9
5.6 End squareness of pipes and fittings.10
6 Determination of other geometrical characteristics related to fittings .11
6.1 General .11
6.2 Bends .12
6.3 Branches .15
6.4 Reducers.17
7 Flanges, loose flanges and collar .18
7.1 General .18
7.2 Outside diameter of the flange, loose flange and collar.20
7.3 Bore diameter of the flange or collar.20
7.4 Bolt hole diameter .20
7.5 Bolt hole distribution.20
7.6 Concentricity of bolt circle diameter.20
7.7 Pitch circle diameter.20
7.8 Shoulder diameter of flange and collar .21
7.9 Flange and collar thickness .21
7.10 Length of the flange and collar.21
8 Other measurements .21
Bibliography .22



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SIST EN ISO 3126:2005
EN ISO 3126:2005 (E)
Foreword

This document (EN ISO 3126:2005) has been prepared by Technical Committee CEN /TC 155, "Plastics piping
systems and ducting systems", the secretariat of which is held by NEN in collaboration with Technical Committee
ISO/TC 138 "Plastics pipes, fittings and valves for the transport of fluids".
This European Standard shall be given the status of a national standard, either by publication of an identical text or
by endorsement, at the latest by September 2005, and conflicting national standards shall be withdrawn at the
latest by September 2005.
This document is one of a series of standards on test methods, which support system standards for plastics piping
systems and ducting systems.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark,
Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

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SIST EN ISO 3126:2005
EN ISO 3126:2005 (E)
1 Scope
This document specifies methods for measurement and/or determination of the dimensions of plastics pipes and
fittings and the accuracy of the measurement.
It specifies procedures for measuring angles, diameters, lengths, squareness and wall thicknesses for the
purposes of checking conformity to geometric limits.
NOTE This document is using metric units. However the procedures and tolerances are applicable to other units by using
appropriate conversion factors.
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/R 463, Dial gauges reading in 0,01 mm, 0,001 in and 0,0001 in.
ISO 3599, Vernier callipers reading to 0,1 and 0,05 mm.
ISO 3611, Micrometer callipers for external measurement.
ISO 6507-1, Metallic materials — Vickers hardness test — Part 1: Test method.
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1.1
accuracy
closeness of agreement between a test result and the accepted reference value
NOTE  The term "accuracy", when applied to a set of test results, involves a combination of random components and a
common systematic error or bias component (ISO 3534-1).
3.1.2
calibration
set of operations that establish, under specified conditions, the relationship between values of quantities indicated
by a measuring instrument or measuring system, or values represented by a material measure or a reference
material, and the corresponding values realised by standards
3.1.3
reference standard
internationally accepted definition of a given unit of measurement
3.2 Symbols
b : distance between the edge of a flange bolt hole and its bore
1
b : distance between the edge of a flange bolt hole and its outside diameter
2
b : distance between the centre of a flange bolt hole and its bore
3
b : distance between the centre of a flange bolt hole and its outside diameter
4
c : distance between the edges of two adjacent flange bolt holes
1
c : distance between the centres of two adjacent flange bolt holes
2
4

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SIST EN ISO 3126:2005
EN ISO 3126:2005 (E)
d : outside diameter of a (part of a) component
e
d : mean inside diameter of the main of a branch
i,m
d : outside diameter of a socket end
1
d : outside diameter of a spigot end
2
d : bore of a flange
3
d : diameter of a flange bolt hole
4
D : outside diameter of a flange
e : wall thickness of a component
k : pitch circle diameter of a flange
L : effective length of a branch
e,b
L : effective length of the main of a branch
e,m
L : effective length of a reducer
e,r
L : effective length of the socket end of a fitting
e,so
L : effective length of the spigot end of a fitting
e,sp
L : length of the straight part of a socket or a spigot end of a fitting
str
L : length of the tapered part of a reducer
t
L : maximum out-of-squareness distance from theoretical
1
L : measured distance from the root of the angle between a straight ruler and a reference surface to the
2
component along the surface
L : measured distance from the root of the angle between a straight ruler and a reference surface to the
3
component along the ruler
L : vertical distance from a reference surface to the nearest point of the upper end
4
L : socket insertion depth
5
L : overall length of a branch main
6
L : distance, measured in the centre-line plane of a branch, between the end of the branch spigot or socket to
7
the bottom of the main
L : overall length of a reducer
8
L : distance between the edges of two selected bolt holes of a flange
9
L : overall length of a flange in axial direction
10
γ : calculated angle of out-of-squareness
θ : angle of bend or branch
4 Measuring devices
4.1 General requirements
4.1.1 Accuracy of measuring devices
The measuring device shall be selected so that together with the associated procedures used the required
accuracy of the measured dimension is obtained.
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SIST EN ISO 3126:2005
EN ISO 3126:2005 (E)
4.1.2 Calibration
Device used for measuring shall be calibrated at regular intervals of time in accordance with the quality plan of the
user of this document. The calibration shall be traceable to an accredited reference standard (see 3.1.3).
4.2 Instruments
4.2.1 Contact instruments
4.2.1.1 In use the instruments shall not apply a force to the surface of the test piece that will cause local
deformation.
4.2.1.2 Measuring devices that require contact between the test piece and one or more surfaces, e.g. a tube
micrometer, shall conform to the following:
a) the surface in contact with the internal surface of a component shall have a radius less than that of the test
piece surface with which it is in contact;
b) the surface in contact with the external surface of a component shall be either flat or radiused;
c) the contact surfaces of the instrument shall have a hardness not less than 500 HV when tested in accordance
with ISO 6507-1.
4.2.1.3 Micrometer callipers shall conform to ISO 3611 if applicable. Vernier callipers shall conform to ISO 3599 if
applicable.
4.2.1.4 If the measuring instrument incorporates a dial gauge, it shall conform to ISO/R 463.
4.2.1.5 If the device comprises a circumference tape (π tape), it shall be graduated in diameters expressed in
millimetres. When a force of 2,5 N is applied in the longitudinal direction to the extremities of the tape, the
elongation of the tape shall not exceed 0,05 mm/m.
4.2.1.6 Measuring instruments may be used in conjunction with a setting standard of calibrated thickness or
length, and then used as a comparator, i.e. to measure small differences between the setting piece and the
measured dimension on the test piece.
NOTE This is particularly recommended when measuring large diameter or thick walled components.
4.2.1.7 Go/no-go gauges may be used for checking conformity to specific limits.
4.2.1.8 Contact instruments other than those mentioned in 4.2.1.3, 4.2.1.4, 4.2.1.5 and 4.2.1.7 may also be used.
Ultrasonic measuring devices shall be regarded as non-contact instruments (see 4.2.2).
4.2.2 Non-contact instruments
If non-contact instruments or devices based on e.g. optical or ultrasonic scanning devices are used, the accuracy
of measurement shall conform to accuracy levels specified in the relevant subclause of Clause 5 or their use shall
be restricted to finding relevant positions for measurements to be made by other means, e.g. points comprising
maximum or minimum dimensions.
5 Determination of dimensions
5.1 General
5.1.1 Ensure that measurement of dimensions is carried out by personnel trained in the applicable equipment
and procedures.
5.1.2 Unless otherwise specified in the referring standard, ensure that either:
a) the temperature of the measuring device, the test piece and the ambient air temperature are at (23 ± 2) °C; or
b) results are correlated by calculation or experience to their value at 23 °C.
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SIST EN ISO 3126:2005
EN ISO 3126:2005 (E)
5.1.3 Examine the test piece surface for any features that could affect dimensional measurements, e.g. marking,
parting lines, blisters or inclusions. If found, record their nature and effects on the measurement.
5.1.4 For selection of the cross-section(s) in which to make measurements, one or more of the following shall
apply, as applicable:
a) select cross-section(s) as specified by the referring standard;
b) identify a cross-section not less than 25 mm from the end or in accordance with the component manufacturer's
specification;
c) for measurements of a dimension associated with another dimension, e.g. to enable calculation of a further
dimension, the cross-section shall be appropriate to the dimension to be calculated.
5.1.5 Results of measurements are rounded as specified in 5.2.3, 5.3.3 and 5.3.4. When determining mean
values the rounding shall be done after the arithmetic mean value has been calculated.
5.2 Wall thicknesses
5.2.1 General
Select instrument(s) or device(s) and associated procedures for measuring wall thickness so that the accuracy of
the result is within the limits given in Table 1, unless otherwise specified in the referring standard.
Table 1 — Measurement of wall thickness
Dimensions in millimetres
Required accuracy of Round arithmetic mean
Wall thickness
a
individual result value to the nearest:
≤ 10 0,03 0,05
> 10 and ≤ 30 0,05 0,1
> 30 0,1 0,1
a
 Exactly intermediate values shall be rounded up.

5.2.2 Maximum and minimum wall thicknesses
Move the measuring device until the positions of the maximum and/or minimum wall thicknesses as appropriate in
the selected cross-sections are found and record the observed value(s).
5.2.3 Mean wall thickness
In each selected cross-section, take at least six measurements of the wall thickness at regular intervals around the
circumference.
From the values obtained, calculate the arithmetic mean value, round in accordance with Table 1 and record the
answer as the mean wall thickness, e .
m
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SIST EN ISO 3126:2005
EN ISO 3126:2005 (E)
5.3 Diameters
5.3.1 General
5.3.1.1 Select the instrument(s) or device(s) and associated procedures for measuring diameters (outside or
inside) of the test piece at the selected cross-section(s), so that the accuracy of the result is in accordance with
Table 2, unless otherwise specified in the referring standard.
Table 2 — Measurement of diameter
Dimensions in millimetres
Nominal diameter Required accuracy of Round arithmetic mean
a
DN individual result
value to the nearest:
≤ 600 0,1 0,1
600 < DN ≤ 1600 0,2 0,2
> 1600 1 1
a
 Exactly intermediate values shall be rounded up.

5.3.1.2 For measuring the diameter(s) of components, select the relevant cross-section(s) in accordance
with 5.1.4.
5.3.2 Measurement of maximum and minimum diameter
Move the measuring device in each selected cross-section until the appropriate extreme value(s) of the diameter
are found and record the observed value(s).
5.3.3 Mean outside diameter
The mean outside diameter, d , may be determined from either:
e,m
a) direct measurement using a π-tape; or
b) a calculated value derived from a series of individual measurements conforming to Table 3, taken at regular
intervals around each of the selected cross-sections.
In case of item b), calculate the arithmetic mean of the individual measurements, round in accordance with Table 2
and record the answer as the mean outside diameter, d .
e,m
Table 3 — Number of individual diameter measurements
for a given nominal size
Nominal size of pipe Number of individual diameter measurements
or fitting required in a given cross section
≤ 40 4
> 40 and ≤ 600 6
> 600 and ≤ 1600 8
> 1600 12

5.3.4 Mean inside diameter
Using a device conforming to 5.3.1.1, determine either:
a) a series of individual measurements conforming to Table 3 at regular intervals; or
b) direct measurement using an inside π-tape.
Calculate the arithmetic mean of the individual measurements obtained in a), round in accordance with Table 2 and
record it as the applicable mean inside diameter, d .
i,m
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SIST EN ISO 3126:2005
EN ISO 3126:2005 (E)
5.3.5 Neutral diameter
Using the values determined in accordance with 5.2 and/or 5.3 without rounding, calculate the mean diameter, d ,
m
using one of the following equations as applicable:
d = d − e ;
m e,m m
d = d + e ;
m i,m m
d = 0,5(d + d ).
m e,m i,m
where:
d is the mean outside diameter at the appropriate cross-section;
...