BS EN 17190-2018 pdf free download.Flexible sheets for waterproofing – Solar Reflectance Index
This European Standard gives a calculation method of the Solar Reflectance Index (SRI) and the determination of solar reflectivity and thermal emissivity for waterproofing flexible sheets for roofs with a slope smaller than 10°.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements 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 15976, Flexible sheets for waterproofing — Determination of emissivity
ASTM C1549-16, Standard test method for determination of solar reflectance near ambient temperature using a portable solar reflectometer
ASTM E1980-11, Standard practice for calculating Solar Reflectance Index of horizontal and low-sloped opaque surfaces
ASTM E903-12, Standard Test Method for Solar Absorptance, Reflectance, and Transmittance of Materials Using Integrating Spheres
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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.iso.org/obp
3.1
Solar Reflectance Index
relative temperature of a surface with respect to the standard white (SRI = 100) and standard black (SRI = 0) under the standard solar and ambient conditions
[SOURCE: ASTM E1980-11, definition 3.1.9]
3.2
solar reflectivity
ratio of the reflected irradiation to the solar irradiation from a surface of the sheet
3.3
thermal emissivity
emissivity of a material (usually written ε) is the ratio (proportion) of the energy radiated by a surface relative to the energy radiated by a blackbody at the same temperature; it is a measure of a material’s ability to radiate heat
[SOURCE: EN 15976:2011, definition 3.1]
4 Sampling
For initial values, take a (new) roll directly from the storage of the manufacture. Unroll the roll over at least 0,5 m and take 5 samples over the width of the sheet.
The surface should be clean to keep the radiative properties of the sheet.
5 Solar reflectivity
Solar reflectivity is measured according to:
— ASTM C1549-16; or
— ASTM E903-12.
Both shall be measured with the solar spectrum according to ASTM E1980-11.
NOTE 1 In the European interlaboratory test it was found within the scattering of the test methods the same results, see [1].
NOTE 2 For the variation of the solar reflectivity, see [1].
6 Thermal emissivity
Thermal emissivity is measured according to EN 15976.
NOTE 1 Thermal emissivity measured according to ASTM C1371 gives within the scattering of the test methods the same results, see [1].
NOTE 2 For the variation of the thermal emissivity, see [1].
7 Solar Reflectance Index
Solar Reflectance Index shall be calculated according to approach I of ASTM E1980-11 for medium wind speed with solar reflectivity measured according to 5 and thermal emissivity measured according to 6.
NOTE 1 The influence of the solar reflectivity is more than 5 times higher than the influence of thermal emissivity on the Solar Reflectance Index.
NOTE 2 Due to the manufacturing process of the sheet, the variation of the SRI can be up to +/-4..
NOTE 3 Due to contamination during the installation of roofs, the SRI value of installed membranes may change typically more than 10 %.
8 Expression of the results
Solar reflectivity and thermal emissivity are indicated as a 2 decimal number. Solar Reflectance Index is indicated as a 0 decimal number.
Average of solar reflectivity and thermal emissivity are used to calculate the SRI.
9 Test report
The test report shall include at least the following information:
a) reference to this document (EN 17190:2018) and any deviation from it;
b) all details necessary to identify the product tested;
c) information on sampling;
d) test methods used;
e) test results on solar reflectivity and thermal emissivity;
f) calculated Solar Reflectance Index value;
g) any peculiarities in the method employed or encountered during the test;
h) date of the test(s).BS EN 17190 pdf download