SIST EN 295-3:2012

SLOVENSKI STANDARD
01-marec-2012
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SIST EN 295-3:1996
SIST EN 295-3:1996/A1:2000
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Vitrified clay pipe systems for drains and sewers - Part 3: Test methods
Steinzeugrohrsysteme für Abwasserleitungen und -kanäle - Teil 3: Prüfverfahren
Systèmes de tuyaux et accessoires en grès pour les réseaux de branchement et
d’assainissement - Partie 3: Méthodes d'essai
Ta slovenski standard je istoveten z: EN 295-3:2012
ICS:
23.040.50 Cevi in fitingi iz drugih Pipes and fittings of other
materialov materials
91.140.80 Drenažni sistemi Drainage systems
93.030 Zunanji sistemi za odpadno External sewage systems
vodo
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 295-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
January 2012
ICS 93.030 Supersedes EN 295-3:1991
English Version
Vitrified clay pipe systems for drains and sewers - Part 3: Test
methods
Systèmes de tuyaux et accessoires en grès vitrifié pour les Steinzeugrohrsysteme für Abwasserleitungen und -kanäle -
collecteurs et branchements - Partie 3: Méthodes d'essai Teil 3: Prüfverfahren
This European Standard was approved by CEN on 19 November 2011.

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 CEN-CENELEC Management Centre 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 CEN-CENELEC Management Centre has the same
status as the official versions.

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

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 295-3:2012: E
worldwide for CEN national Members.

Contents Page
Foreword .5
1 Scope .6
2 Normative references .6
3 Terms and definitions .6
4 Symbols and abbreviations .7
5 Test for squareness of ends .8
5.1 Test of squareness of ends for pipes according to EN 295-1:2012 .8
5.2 Test of squareness of ends for pipes according to EN 295-7:2012 .8
6 Straightness test .9
7 Crushing strength test . 10
7.1 General . 10
7.1.1 Preconditioning . 10
7.1.2 Testing machine. 11
7.1.3 Loading . 11
7.2 Bearers and bearing strips/facings. 11
7.2.1 Bearers . 11
7.2.2 Bearing strips/facings . 12
7.3 Support system . 12
7.3.1 Flexible hose system (for use with any length of pipe, or pipe section not less than 300
mm in length) . 12
7.3.2 Common hydraulic manifold system (for use with any length of pipe, or pipe section not
less than 300 mm in length) . 14
7.3.3 Rigid systems (restricted to use with pipes or pipe sections from 300 mm to 1 100 mm
nominal length) . 14
7.4 Test load application . 14
7.4.1 Plain ended pipes . 14
7.4.2 Socketted pipes . 14
7.4.3 Loading . 14
7.5 Results and reporting . 14
7.5.1 Acceptance (proof) tests . 14
7.5.2 Ultimate tests . 15
7.5.3 Disputes . 15
7.5.4 Test records . 15
8 Bending tensile test . 15
8.1 Preconditioning . 15
8.2 Test procedure . 15
9 Bending moment resistance (BMR) test. 17
9.1 General . 17
9.1.1 Preconditioning . 17
9.1.2 Testing machine. 17
9.1.3 Loading . 17
9.1.4 Choice of test method . 17
9.2 Four point loading test . 17
9.2.1 Test procedure . 17
9.2.2 Testing by attributes . 18
9.2.3 Testing by variables . 18
9.3 Three point loading test . 18
9.3.1 Test procedure . 18
9.3.2 Testing by attributes . 19
9.3.3 Testing by variables . 19
10 Bond strength of adhesive . 20
11 Tests for fatigue strength . 20
11.1 Preconditioning . 20
11.2 Test using a pipe or pipe section . 20
11.3 Test using sawn test specimens . 21
12 Test for watertightness . 22
12.1 General . 22
12.2 Pipes and junctions . 22
12.3 Fittings other than junctions and terminal fittings . 22
13 Chemical resistance test for pipes and fittings. 22
14 Determination of hydraulic roughness . 23
15 Abrasion resistance test . 23
16 Airtightness test . 25
17 Tests for resistance to high pressure jetting . 25
17.1 General . 25
17.1.1 Water source . 25
17.1.2 Pressure measurement . 25
17.1.3 Test temperature . 25
17.2 Moving jet test . 26
17.3 Stationary jet test . 26
17.3.1 General . 26
17.3.2 Apparatus . 26
17.3.3 Test pieces . 27
17.3.4 Procedure . 27
18 Hardness test for polyurethane . 28
18.1 Test pieces . 28
18.2 Test method . 28
19 Tests for material requirements of polypropylene sleeve couplings . 28
19.1 Melt flow index . 28
19.2 Tensile strength and elongation at break . 29
19.3 Elevated temperature test. 29
20 Performance test for polypropylene sleeve couplings . 29
21 Mechanical test methods for joint assemblies . 29
21.1 General . 29
21.2 Deflection test . 30
21.3 Shear resistance test . 31
21.3.1 Loading arrangements for shear resistance . 31
21.3.2 Short-term shear resistance test . 33
21.3.3 Long-term shear resistance test . 33
22 Continuity of invert test . 34
22.1 Test methods . 34
22.2 Pipes and fittings with top marking . 34
22.3 Pipes and fittings randomly jointed . 35
22.3.1 Sampling and dimensions . 35
22.3.2 Calculations . 35
22.3.3 Evaluation. 36
23 Chemical resistance test for joint assemblies . 36
23.1 Test solutions . 36
23.2 Procedure . 36
24 Thermal stability . 37
24.1 Thermal cycling stability . 37
24.2 Long-term thermal stability . 37
25 Creep resistance of rigid fairing materials . 38
25.1 Deformation . 38
25.1.1 Test samples . 38
25.1.2 Test apparatus . 38
25.1.3 Procedure . 38
25.2 Indentation . 38
25.2.1 Test samples . 38
25.2.2 Test apparatus . 39
25.2.3 Procedure . 39
26 Water tightness test for assembled components of manholes and inspection chambers . 39
27 Compressive strength of jacking pipes . 39
27.1 Test methods . 39
27.1.1 Testing machine. 39
27.1.2 Selection and preparation of specimens . 39
27.1.3 Test procedure . 41
27.1.4 Loading . 41
27.2 Calculation of compressive strength. 41
28 Water absorption . 41
28.1 Test specimen . 41
28.2 Water absorption test . 42

Foreword
This document (EN 295-3:2012) has been prepared by Technical Committee CEN/TC “Wastewater
engineering”, the secretariat of which is held by DIN.
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 July 2012, and conflicting national standards shall be withdrawn at the
latest by January 2013.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 295-3:1991.
The main changes with respect to the previous edition are listed below:
a) test method for resistance to high pressure water jetting added;
b) test method for water absorption added;
c) test methods from the previous parts 4, 5, 6 and 7 have been included in this European Standard;
d) editorially revised.
The standard series EN 295 "Vitrified clay pipe systems for drains and sewers" consists of the following parts:
 Part 1: Requirements for pipes, fittings and joints;
 Part 2: Evaluation of conformity and sampling;
 Part 3: Test methods;
 Part 4: Requirements for adaptors, connectors and flexible couplings;
 Part 5: Requirements for perforated pipes and fittings;
 Part 6: Requirements for components of manholes and inspection chambers;
 Part 7: Requirements for pipes and joints for pipe jacking.
This European Standard takes into account the requirements of EN 476.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland, Turkey and the United Kingdom.
1 Scope
This European Standard specifies requirements for testing of products manufactured from vitrified clay and
other materials specified in the following standards:
 pipes, fittings and joints according to EN 295-1;
 adaptors, connectors and flexible couplings according to EN 295-4;
 perforated pipes and fittings according to EN 295-5;
 components of manholes and inspection chambers according to EN 295-6;
 pipes and joints for pipe jacking according to EN 295-7.
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.
EN 295-1:2012, Vitrified clay pipe systems for drains and sewers — Part 1: Requirements for pipes, fittings
and joints
EN 295-4:2012, Vitrified clay pipe systems for drains and sewers — Part 4: Requirements for adaptors,
connectors and flexible couplings
EN 295-5:2012, Vitrified clay pipe systems for drains and sewers — Part 5: Requirements for perforated pipes
and fittings
EN 295-6:2012, Vitrified clay pipe systems for drains and sewers — Part 6: Requirements for components of
manholes and inspection chambers
EN 295-7:2012, Vitrified clay pipe systems for drains and sewers — Part 7: Requirements for pipes and joints
for pipe jacking
EN ISO 527-2:1996, Plastics — Determination of tensile properties — Part 2: Test conditions for moulding and
extrusion plastics (ISO 527-2:1993 including Corr 1:1994)
EN ISO 868, Plastics and ebonite — Determination of indentation hardness by means of a durometer (Shore
hardness) (ISO 868)
EN ISO 1133:2005, Plastics — Determination of the melt mass-flow rate (MFR) and the melt volume-flow rate
(MVR) of thermoplastics (ISO 1133:2005)
CEN/TR 14920:2005, Jetting resistance of drain and sewer pipes — Moving jet test method
3 Terms and definitions
For the purposes of this European Standard, the relevant terms and definitions specified in EN 295-1:2012,
EN 295-4:2012, EN 295-5:2012, EN 295-6:2012 and EN 295-7:2012 apply.
4 Symbols and abbreviations
Symbol Description
A Outside diameter of the spigot moulding
a Measurement from inside of pipe barrel to mid point of inside of socket fairing, in millimetres
M
(continuity of invert test).
a Width of top bearer, in millimetres (crushing strength test and bending tensile strength test).
p
B Nominal length of external barrel of pipe unobstructed by socket shape and/or jointing
configuration, in millimetres (crushing strength test).
B Distance from the outside surface of the spigot moulding to the internal surface of the pipe at
t
one point at which the outside diameter of the spigot moulding (A) was measured, in millimetres
(continuity of invert test).
b Specimen width, in millimetres (fatigue strength test).
C Distance from the outside surface of the spigot moulding to the internal surface of the pipe at the
t
opposite end to B of the diameter measured as the outside diameter of the spigot (A), in
t
millimetres (continuity of invert test).
c Concentration of solution, in moles per litre (chemical resistance tests).
c Factor for the upper (0,4) or lower (0,1) limit of the load (fatigue strength test).
i
D
Inside diameter of the socket moulding
DN Nominal size - a numerical designation of size which is a convenient round number equal to or
approximately equal to the internal diameter, in millimetres (bending moment resistance test).
D Deviation from straightness
S
d
Barrel internal diameter, in millimetres (bending tensile strength test).
E Distance from the internal surface of the socket moulding to the internal surface of the pipe at
t
one point at which the inside diameter of the socket moulding (D) was measured, in millimetres
(continuity of invert test).
F Force for upper and lower limit, in kilonewtons (fatigue strength test).
i
F Crushing strength, in kilonewtons per metre.
N
F Distance from the internal surface of the socket moulding to the internal surface of the pipe at
t
the opposite end to E, of the diameter measured as the inside of the socket moulding (D), in
t
millimetres (continuity of invert test)
G Mean annular gap, in millimetres (continuity of invert test).
m
IRHD International Rubber Hardness Degrees of bearing strips/facings, in degrees IRHD (crushing
strength test).
k Hydraulic roughness in millimetres
s
l Centre line distance between supports, in millimetres (fatigue strength test).
L Nominal length of the pipe
N
L Test length
T
M Bending moment resistance, in kilonewton metres (bending moment resistance test).
M Bending moment, in Newton millimetres (bending tensile strength test).
b
M Mean particle size, in millimetres (abrasion resistance test).
p
M Test piece mass before treatment, in grammes (chemical resistance test).
M Test piece mass after treatment, in grammes (chemical resistance test).
S Support span in metres
s Specimen wall thickness, in millimetres (bending tensile test).
S S Extreme values of difference in invert, in millimetres (continuity of invert test).
min, max
S Standard deviation, in millimetres (continuity of invert test).
t
s Specimen wall thickness, in millimetres (fatigue strength test).
f
t
Time.
U
Degree of non-uniformity of particles (abrasion resistance test).
W
Water addition in 15 minutes, in litres per square metre (watertightness test).
Half the depth of a socket fairing, in millimetres (continuity of invert test).
β
∆ a Measurement of difference in invert levels, in millimetres (continuity of invert test).
∆s Deviation from squareness in millimetres.
Deformation of rigid fairing materials (creep resistance of rigid fairing materials test).
ε
i j 2
σ σ Restoring stress at t = 10 and t = 10 , in N/mm (polyurethane relaxation tests).
i, j
Bending tensile strength, in Newtons per square millimetre (bending tensile strength test).
σ
bz
5 Test for squareness of ends
5.1 Test of squareness of ends for pipes according to EN 295-1:2012
A whole pipe shall be placed horizontally on two supports which have a distance of 75 mm from each end of
the barrel for up to and including DN 500 and 100 mm for pipes greater than DN 500.
The deviation from squareness shall be measured as the maximum difference, at either end, between
distances from any point on the end of the barrel to a plane rectangular to the line joining the points of
support. Any suitable apparatus may be used. An example is given in Figure 1.

Figure 1 — Measurement of squareness of ends
5.2 Test of squareness of ends for pipes according to EN 295-7:2012
A whole pipe shall be placed on a horizontal support according to Figure 2. The gauge shall be clamped to the
ground ends of the pipe. The pivot arm is located approximately 100 mm away from the cut end.
The distance between the pivot arm and the cut end is measured at 90° intervals. The deviation from
squareness is the difference between the maximum and minimum measurements. This procedure shall be
performed for both ends of the pipe. Any suitable apparatus may be used. An example is given in Figure 2.

Key 4 calliper gauge
1 gauge 5 pivot arm
2 clamp 6 spirit level
3 support
Figure 2 — Gauge for squareness of ends
6 Straightness test
The deviation from straightness of a pipe barrel is the maximum distance from the centre of a straight line
equal to the test length spanning any concave curve on the outside of a pipe barrel to the pipe surface, D , as
s
shown in Figure 3. It is permissible to test for straightness using any suitable apparatus.
The test length shall be 150 mm less than the nominal length of the pipe to allow for clearance at the shoulder
of any socket and at any jointing material at the spigot end.
Key
L is the nominal length of the pipe
N
is the test length
L
T
D is the deviation from straightness
s
L = L – 150 mm at DN ≤ 500
T N
L = L – 200 mm at DN > 500
T N
Figure 3 — Straightness test method
7 Crushing strength test
7.1 General
7.1.1 Preconditioning
Prior to crushing strength tests, sample pipes or pipe sections shall be preconditioned by either:
a) complete immersion in water at ambient temperature for the minimum times given in Table 1, where the
wall thickness is the mean wall thickness of the batch,
Table 1 — Preconditioning time for strength tests
Minimum preconditioning time
Wall thickness
Unglazed, glazed only on interior or Ceramic glazed

exterior surface, salt glazed
mm
h h
up to 20 18 42
42 66
> 20 to ≤ 35
> 35 66 90
or
b) by complete immersion in a water pressure tank at ambient temperature for 24 h at a pressure of 250 kPa
(2,5 bar).
An example of the pressure tank is given in Figure 4.
Figure 4 — Example of pressure tank for preconditioning
7.1.2 Testing machine
The testing machine for crushing shall be capable of applying compressive loads and shall be substantial and
rigid throughout, so that the distribution of the load will not be affected by the deformation or yielding of any
part. The machine and bearers shall be designed to transmit the load in a vertical plane through the
longitudinal centre lines of the bearers and pipe.
The load shall be applied to the top bearer in such a way that the combination of support, bearers and bearing
strips is free to rotate in a vertical plane through the longitudinal centre lines of the top and custom bearers.
The testing machine load shall be verified by calibration to an accuracy of 1 % by an approved agency at
intervals of not more than 12 months.
7.1.3 Loading
The pipe or pipe section of no less than 300 mm long shall be placed between the bearer strips. When using
the rigid system described in 7.3.3 the plane of any permitted longitudinal curvature shall be approximately
horizontal.
The load shall be applied to the pipe or pipe section without vibration or sudden shock, at a uniform rate
between 0,40 kN/m of pipe per second and 0,60 kN/m of pipe per second, or in increments of not more than
0,50 kN/m at the same rate, up to the point of failure or, in the case of acceptance (proof) testing, to the load
corresponding to the required strength.
7.2 Bearers and bearing strips/facings
7.2.1 Bearers
The bearers shall consist of metal, teak or similar hard wood, be straight and free from knots, warping or
twisting, and shall be centrally located on their supports.
The top and bottom bearers shall both have a minimum thickness of 25 mm. When bearing strips are used the
widths of the bearers shall be not less than those of the corresponding bearer strips as shown in Figure 5 a).
Bearers shall be located such that they are aligned both longitudinally and transversely.
When bearing facings are used, the widths shall be as necessary to support the pipe and the width of the top
bearer shall not be less than the values given in Table 2, see Figure 5 b).
The cross-sectional shape of the bearers shall be in accordance with Figure 5. The slope of the V surface of
the bottom bearer shall be between 0° and 5°.
Table 2 — Width a of the top bearer when bearing facings are used
p
DN 100 to 225 and 300 350 400 450 500 600 700 800 900 1000 > 1000
200 250
a 25 30 35 45 50 55 60 75 85 95 105 115 DN/9
p
7.2.2 Bearing strips/facings
Bearing strips shall consist of elastomeric material having a hardness of (55 ± 10) IRHD.
Strips shall be of rectangular cross section having a width of (50 ± 5) mm and a thickness of not less than
25 mm or more than 40 mm. The 50 mm dimension shall be in contact with the pipe.
The top bearing strip shall be concentric with the top bearer. The bottom bearing strips shall be symmetrically
arranged on the bottom bearer, of equal thickness and parallel to one another at a distance apart of
(25 ± 5) mm.
Facings shall be either
a) of elastomeric material of thickness not less than 15 mm nor more than 30 mm and of hardness
(55 ± 10) IRHD, or
b) of felt of thickness (20 ± 2) mm and a density of (0,3 ± 0,025) g/cm .
7.3 Support system
7.3.1 Flexible hose system (for use with any length of pipe, or pipe section not less than 300 mm in
length)
The overall bearer length shall be (B - 50) mm for pipes up to and including 1 500 mm nominal length and
(B - 100) mm for pipes greater than 1 500 mm nominal length, where B is the nominal length (in millimetres) of
the external barrel unobstructed by socket shape and/or jointing configuration at either end (see Figure 6).
The top and bottom bearers shall be divided, along their length, into separate segments. These segments
shall be supported by flexible high pressure hoses which are closed at each end. These hoses shall be filled
with liquid and carried in U shaped channels below the bottom bearers and above the top bearers. Each
segment shall be of the same length which shall not be greater than 300 mm except for individual shorter
sections used to make up the overall bearer length. Alternatively, any excess of bearer length over the total
length of segments may be distributed evenly as gaps between the segments. No gap shall be greater than
one third of the length of a bearer segment. The length of each bearing strip or facing may be equal to the
length of its appropriate segment.
a) — Bearer shape for bearing strips
b) — Bearer shape for bearing facings
Key
a width of the top bearer 5 bearing strip
p
6 bottom bearer
1 load
7 facing
2 top bearer
8 elastomeric or felt facing
3 bearing strip
9 slope of the V surface (0° to 5°)
4 gap width (25 ± 5) mm
Figure 5 — Bearer shape
b) — Example pipe length > 1,5 m
a) — Example pipe length ≤≤≤≤ 1,5 m
NOTE Segmented bearers can be used for all nominal pipe lengths. Rigid bearers can only be used for pipes of
nominal length ≤ 1,1 m.
Key
1 load
2 top bearer
3 bottom bearer
B pipe nominal length
Figure 6 — Typical arrangement for crushing strength test
7.3.2 Common hydraulic manifold system (for use with any length of pipe, or pipe section not less
than 300 mm in length)
The overall bearer length shall be (B - 50) mm for pipes up to and including 1 500 mm nominal length and
(B - 100) mm for pipes greater than 1 500 mm nominal length, where B is the nominal length (in millimetres) of
the external barrel unobstructed by socket shape and/or jointing configuration at either end of the pipe (see
Figure 6).
The top and bottom bearers shall be divided along their length into separate segments. Each segment shall
be supported by a common hydraulic system to provide uniform load along the length of the pipe barrel. The
segments shall be of the same length which shall not be greater than 300 mm.
The length of each bearing strip or facing shall be equal to the length of each bearer segment.
The distance by which the overall bearer exceeds the total length of the bearer segment shall be distributed
evenly as gaps between the segments. No gap shall be greater than one third of a bearer segment. No part of
any bearer segment shall overhang either end of the pipe.
7.3.3 Rigid systems (restricted to use with pipes or pipe sections from 300 mm to 1 100 mm nominal
length)
The overall length of each bearing strip/facing shall be (B - 50) mm, where B is the nominal length (in
millimetres) of the external barrel unobstructed by socket shape and/or jointing configuration at either end (see
Figure 6).
The overall bearer length shall not be less than the length of the bearer strip/facing. No part of any bearing
strip or facing shall overhang either end of the pipe.
7.4 Test load application
7.4.1 Plain ended pipes
The test load shall be applied at the longitudinal centre of the overall bearer length for the systems described
in 7.3.1 and 7.3.2, and at the longitudinal centre of the overall bearing strip/facing length for the system
described in 7.3.3.
7.4.2 Socketted pipes
The test load of the systems described in 7.3.1 and 7.3.3 shall be applied at the positions given in 7.4.1. For
the system described in 7.3.2 the position of the application of the test load should be adjusted to maintain
horizontal stability.
7.4.3 Loading
The loading of the pipe shall be continuous operation. The pipe shall not be allowed to stand under load
longer than is required to apply the load and to record the results when proof tests are being conducted.
7.5 Results and reporting
7.5.1 Acceptance (proof) tests
For tests on pipes sampled for testing by attributes the total test load to be applied in kN shall be calculated by
multiplying the required crushing strength in kN/m by the nominal inside length of the barrel in m.
7.5.2 Ultimate tests
For tests on pipes sampled for testing by variables the crushing strength in kN/m is calculated by dividing the
ultimate applied load at failure by the nominal inside length of the barrel in m.
If the bending tensile strength σ is required, it can be calculated from the following equation using the
bz
symbols from 8.2
d + s 6
1 1
σ = 0,3 ⋅ F ⋅ ⋅α (1)
bz N K
s
7.5.3 Disputes
Where any dispute over the verification of crushing strength arises, the tests shall be carried out using the
same method as the manufacturer.
7.5.4 Test records
As well as the test results and other relevant details, the records shall contain the following additional informa-
tion:
a) method of preconditioning;
b) angle of slope of the lower support bearer;
c) whether bearing strips or facings were used, if so whether elastomeric material or felt;
d) type of support system, 7.3.1, 7.3.2 or 7.3.3, if 7.3.1 or 7.3.2, the nominal segment length.
8 Bending tensile test
8.1 Preconditioning
Prior to bending tensile test, test pieces shall be preconditioned by complete immersion in water for the
minimum times given in 7.1.1.
8.2 Test procedure
The bending tensile test shall be carried out on ten specimens having parallel surfaces, sawn from broken
pieces distributed over the length and circumferences of a pipe. The dimensions shall be selected so that their
length is approximately five times their wall thickness and their width approximately three times the wall
thickness.
The long sides of the specimens shall be at right angles on the pipe axis. The specimens shall be supported
so that free movement of one bearer is ensured. The force shall be applied centrally by means of a steel
pressure beam with a rubber facing (Shore A hardness: (60 ± 5); thickness 3 mm). The width, a , of the
p
pressure beam (top bearer) shall correspond to one tenth of the wall thickness of the specimen (see Figure 7)
with a minimum of 2,5 mm.
a) Elevation b) Cross-section A - A
Key
L centreline distance between supports
1 pressure bar 4 rubber facing
2 pressure beam a width of top bearer
p b specimen width
3 rubber facing
F force at failure
B s specimen wall thickness
Figure 7 — Test arrangement for bending tensile strength
The test force shall be increased steadily and smoothly until the specimen fails. The bending tensile strength
determined from the force at failure can be calculated from the following equation:
α 1000 F ⋅ L 6
K B 3
σ = M ⋅ = ⋅ ⋅α (2)
bz b K
W 4b s
3 1
with
3 d + 5 s
1 1
α = (3)
K
3 d + 3 s
1 1
The corresponding crushing strength shall be calculated from the following equation:
1000 2 F ⋅ L
B 3
F = ⋅ ⋅ (4)
N
0,3 d + s 4 b
1 1 3
where
σ  is the bending tensile strength, in N/mm ;
bz
F  is the force, at failure, in kN;
B
L  is the centre line distance between supports, in mm;
b is the specimen width, in mm;
d is the barrel internal diameter, in mm;
s is the specimen wall thickness, in mm;
α  is a correction factor;
k
F is the crushing strength, in kN/m;
N
M is the bending moment, in Nmm;
b
W is the section modulus, in mm .
The testing machine load shall be verified by calibration to an accuracy of 1 % by an approved agency at
intervals of no more than 12 months.
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