EN ISO 9967:1995
(Main)Plastics pipes - Determination of creep ratio (ISO 9967:1994)
Plastics pipes - Determination of creep ratio (ISO 9967:1994)
Thermoplastische Rohre - Bestimmung des Kriechverhaltens (ISO 9967:1994)
Diese internationale Norm legt ein Verfahren zur Bestimmung des Kriechverhaltensvon thermoplastischen Rohren mit rundem Querschnitt fest.
Tubes en matières thermoplastiques - Détermination du taux de fluage (ISO 9967:1994)
Cevi iz polimernih materialov - Določevanje razmerja lezenja
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 9967:1997
01-februar-1997
&HYLL]SROLPHUQLKPDWHULDORY'RORþHYDQMHUD]PHUMDOH]HQMD
Plastics pipes - Determination of creep ratio (ISO 9967:1994)
Thermoplastische Rohre - Bestimmung des Kriechverhaltens (ISO 9967:1994)
Tubes en matieres thermoplastiques - Détermination du taux de fluage (ISO 9967:1994)
Ta slovenski standard je istoveten z: EN ISO 9967:1995
ICS:
23.040.20 Cevi iz polimernih materialov Plastics pipes
SIST EN ISO 9967:1997 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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INTERNATIONAL IS0
STANDARD 9967
First edition
1994-03-01
Thermoplastics pipes - Determination of
creep ratio
Dhtermina tl’on du taux de fluage
Tubes en mat&es thermoplastiques -
Reference number
IS0 9967: 1994(E)
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IS0 9967: 1994(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work
of preparing International Standards is normally carried out through IS0
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. IS0
collaborates closely with the International Electrotechnical Commission
(I EC) on all matters of electrotechnical standardization.
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.
International Standard IS0 9967 was prepared by Technical Committee
lSO/TC 138, Plastics pipes, fittings and valves for the transport of fluids,
Sub-Committee SC 1, Plastics pipes and fittings for soil, waste and drain-
age (including land drainage).
Annexes A and B of this International Standard are for information only.
0 IS0 1994
All rights reserved. No part of this publication may be reproduced or utilized in any form or
by any means, electronic or mechanical, including photocopying and microfilm, without per-
mission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
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IS0 9967:1994(E)
Introduction
Experience shows that, when a pipe is installed in the ground in accord-
ance with an appropriate code of practice, its increase in deflection virtu-
ally stops after a short period. This period varies depending on the soil and
installation conditions, but it does not exceed two years.
Therefore the two-year creep ratio as determined in accordance with this
International Standard is intended for use when long-term static calcu-
lations are carried out.
The theory of creep in thermoplastics materials is briefly explained in an-
nex A.
For experiments, the test can be carried out based on other ages of the
test pieces, other test temperatures and/or other testing times.
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INTERNATIONAL STANDARD IS0 9967:1994(E)
Thermoplastics pipes - Determination of creep ratio
1 Scope 4 Apparatus
This International Standard specifies a method of de-
4.1 Compressive-testing machine, capable of ap-
termining the creep ratio of thermoplastics pipes
plying to the pipe via plates (4.2), and maintaining to
having a circular cross-section.
within 1 %, both the applicable pre-load force F0 (see
7.4) and the necessary loading force F (see 7.5).
2 Symbols
4.2 Two steel plates, through which the
The following symbols are used in this International
compressive force can be applied to the test piece.
Standard:
The plates shall be flat, smooth and clean and shall
not deform during the test to an extent that would
Units
affect the results.
nominal diameter of pipe mm
4-l
The length of each plate shall be at least equal to the
inside diameter of pipe test piece m
4
length of the test piece. The width of each plate shall
F loading force kN
be not less than the maximum width of the surface
pre-load force N
FO in contact with the test piece while under load plus
25 mm.
L length of test piece m
measured initial deflection m
Yo
4.3 Measuring devices, capable of determining
calculated deflection at time t m
rt
extrapolated two-year deflection m
r2
- the length of the test piece to within 1 mm (see
.
6 vertical deflection used to determine the m
.
5 2) I
loading force
creep ratio
- the inside diameter of the test piece to within
Y
0,5 %;
3 Principle
- the change in inside diameter of the test piece in
the direction of loading with an accuracy of
A cut length of pipe is placed between two parallel flat
0,l mm, or 1 % of the deflection, whichever is the
horizontal plates and a constant compressive force is
greater.
applied for 1 000 h (42 days).
An example of a device for measuring the inside di-
The deflection of the pipe is recorded at specified in-
ameter of corrugated pipes is shown in figure 1.
tervals so as to prepare a plot of pipe deflection
against time. The linearity of the data is analysed and
the creep ratio is calculated. 4.4 Timer.
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IS0 9967: 1994(E)
Figure 1 - Example of a device for measuring the inside diameter of a corrugated pipe .
5.2.3 For pipes that have nominal diameters greater
5 Test pieces
than 1 500 mm, the average length, in millimetres, of
each test piece shall be at least 0,2&.
5.1 Marking and number of test pieces
5.2.4 Structured-wall pipes with perpendicular ribs
or corrugations or other regular structures shall be cut
The pipe for which the creep ratio is to be determined
such that each test piece contains the minimum
shall be marked on the outside along its full length
whole number of ribs, corrugations or other structures
with a line along one generatrix. Three test pieces, a,
necessary to satisfy the requirement on length given
b and c, respectively, shall be taken from this marked
in 5.2.2 or 5.2.3, as applicable (see figure2).
pipe such that the ends of the test pieces are per-
The cuts shall be made at the mid-point between the
pendicular to the pipe axis and their lengths conform
ribs, corrugations or other structures.
to 5.2.
L = 7p
5.2 Length of test pieces
- -
5.2.1 The length of each test piece shall be deter-
mined by calculating the arithmetic mean of three to
six length measurements equally spaced around the
perimeter of the pipe as given in table 1. The length
of each test piece shall conform to 5.2.2, 5.2.3, 5.2.4
or 5.2.5, as applicable.
Each of the three to six length measurements shall
be made to within 1 mm.
For each individual test piece, the smallest of the
three to six length measurements shall not be less
than 0,9 times the largest measurement.
Table 1 - Number of length measurements
0,5P
Nominal diameter d, of
Number of length
the pipe
measurements
e.g. p = 45 mm
mm
- Test piece cut out of a
Figure 2
d& 200 3
perpendicularly ribbed pipe
ZOO
d,> 500 6
5.2.5 For helically wound pipes (see figure3), the
length of each test piece shall be such that it contains
5.2.2 For pipes that have nominal diameters less the minimum whole number of helical windings
than or equal to 1 500 mm, the average length of necessary to satisfy the requirement on length given
each test piece shall be 300 mm & 10 mm. in 5.2.2 or 5.2.3, as applicable.
2
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IS0 9967:1994(E)
For pipes with helical stiffeners in the form of ribs,
6 Conditioning
corrugations, etc., the length of each test piece shall
be such that it comprises a whole number of
Condition the test pieces in air at the test temperature
stiffeners, with a minimum of three, and shall con-
(see 7.1) for at least 24 h immediately prior to testing.
form to 5.2.2 or 5.2.3, as applicable.
7 Procedure
L = 5p
7.1 Unless otherwise specified in the referring
standard, carry out the test procedure at
23 “C + 2 “C or, in countries where 27 “C is used as
the standard laboratory temperature, at 27 “C + 2 “C.
In cases of dispute, 23 “C + 2 “C shall be used.
-
7.2 If it can be determined in which position the test
piece has the lowest ring stiffness, place the first test
piece a in this position in the compressive-testing
machine.
Otherwise, place the first test piece in such a way
that the marking line is in contact with the upper
plate.
Rotate the two others b and c by 120” and 240”, re-
spectively, in relation to the first test piece when
P
placing them in the testing machine.
b---i
7.3 For each test piece, attach the deflection gauge
e.g. p = 65 mm
and check the angular position of the test piece with
respect to the upper plate.
Figure 3 - Test piece cut out of a helically
wound pipe
7.4 Lower the upper plate until it touches the upper
part of the test piece.
Apply one of the following pre-load forces Fo, as ap-
plicable, taking into account the mass of the upper
plate:
5.3 Inside diameter of test pieces
a) for pipes with di less than or equal to 0,l m, F0
Determine the inside diameters a&, dib and a& of the
shall be 7,5 N;
respective test pieces a, b and c (see 5.1) as the
arithmetic mean of four measurements obtained at
b) for pipes with di larger than 0,l m, calculate F0 in
45” intervals on one cross-section at mid-length, each
newtons, using the following equation and round-
measurement being made to within 0,5 %.
ing the result to the next highest whole number:
Record the calculated mean inside diameter dial Q& and
F. = 754
die for each test piece a, b and c, respectively.
where di is the numerical value of 4 measured in
Calculate the average value 4 of these three values
metres.
using the following equation:
7.5 Within 5 min of applying the pre-load force, set
di, + & + dig
.=
d
I the deflection gauge to zero and start applying a
3
steadily increasing compressive force such that, be-
tween 20 s and 30 s after starting, a loading force F
is reached. This force F shall be chosen such that af-
ter 360 s (6 min) the test piece shows a deflection
5.4 Age of test pieces
ratio of 1,5 % + 0,2 %, i.e.
-
6
At the start of the test, the age of the test pieces shall
- = 0,015 + 0,002
-
d
be 21 days + 2 days. i
At the moment when this full loading force F is
NOTE 1 For the determination of the creep ratio of pipes
with ages outside these limits, see annex B. rea ched, start the timer.
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IS0 9967: 1994(E)
7.6 Determine the i
...
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