EN 479-2018 pdf download.Plastics – Poly ( vinyl chloride ) ( PVC ) based profiles Determination of heat reversion.
This EN 479 specifies a method for determining the heat reversion of unplasticized poly(vinyl chloride) (PVC-Li) profiles at 100°C in air.
It is also applicable to PVC-based profiles at specified temperatures/other test conditions.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.lso.org/obp
4 Principle
A test specimen of a specified length of profile is maintained in an oven at 100°C for 1 Ii.
A marked length of this test specimen is measured under identical conditions, before and after heating in the oven.
The heat reversion is calculated as the percentage change of the final length relative to the initial length per pair of marks.
5 Apparatus
5.1 Mr oven, thermostatically controlled, with forced air circulation, in which the test specimens can be exposed to a temperature of 100 °C.
The oven shall be equipped with a thermostat capable of maintaining the temperature at (100 ± 3) °C and a support system which keeps the specimen in position and enables heat transfer.
NOTE The use of talc or PTFE foil can be convenient to avoid sticking.
5.2 Measuring device, to measure the length of the test specimen to an accuracy of 0,1 mm.
6 Test specimens
6.1 The test specimen shall be of a minimum length of 250 mm of profile.
6.2 Prepare three similar test specimens per length of profile.
7 Conditioning
Condition the test specimens for at least I h at room temperature.
In cases of dispute the test specimens shall be conditioned at (23 ± 2) °C.
8 Procedure
8.1 Using, a scriber or similar implement, trace on each test specimen two marks, perpendicular to the profile axis, 200 mm apart, so that one of them is approximately 25 mm from one end of the test specimen.
8.2 Measure for every test specimen at room temperature the distance between the two marks in one pair with an accuracy of 0.1 mm.
8.3 Set the oven temperature to 100 °C.
8.4 When the oven has reached 100 °C, place the test specimens horizontally in the oven on the support system.
8.5 Maintain the test specimens in the oven for (60 0 mm, after the temperature has regained to
100°C.
8.6 Remove the support system with the test specimens from the oven and let them cool down in air
to room temperature on the support system.
Under identical conditions to those used in 8.2, measure the distance between the two marks per pair.
8.7 In cases of dispute the cooling of the profiles and the measuring of the distance between the
marks shall be performed at (23 ± 2) °C.
9 Expression of results
For each test specimen, calculate the heat reversion R for each pair of marks, as a percentage using the following formula
R=x10()
10
where
liLL0—L1
L0 is the distance between the marks before heating in the oven in millimetres;
L1 is the distance, between the marks, after heating in the oven in millimetres.
Where relevant, calculate for each test specimen the difference of the values of the heat reversion, R, expressed as a percentage, between the two opposing surfaces, as defined in the referring standard.
10 Test report
The test report shall include the following information:
a) reference to this document (i.e. EN 479);
b) the test laboratory;
c) full identification of the profile;
d) the date of testing;
e) the distance between the marks before heating in the oven (L0) for each pair of marks of each test specimen;
f) the distance between the marks after heating in the oven (L1) for each pair of marks of each test specimen;
g) the value R for each pair of marks for each test specimen;
h) the difference of the values of the heat reversion, 1R, for each test piece, where relevant;
I) all operating details not specified In this document, as well as any incidents likely to have influenced the results.EN 479-2018 pdf download.