BS EN ISO 13468-2:2006
$102.76
Plastics. Determination of the total luminous transmittance of transparent materials – Double-beam instrument
| Published By | Publication Date | Number of Pages |
| BSI | 2006 | 16 |
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 3 | Contents |
| 8 | Contents |
| 9 | Foreword |
| 11 | 1 Scope 2 Normative references 3 Terms and definitions 3.1 transparent plastics 3.2 total spectral transmittance 3.3 total luminous transmittance 4 Apparatus 4.1 The apparatus shall consist of the following elements: |
| 12 | Figure 1 – Schematic arrangement of the integrating sphere (baffles not shown) 4.2 The value of the total luminous transmittance determined by the instrument shall be accurate to ± 1,0 %. To fulfill this req… 4.3 The optical system shall produce two parallel beams; the angle which any ray of either of these beams makes with the axis of the beam shall not exceed 0,087 rad (5°). The beams shall not be vignetted at either port of the sphere. 4.4 Using this instrument, the repeatability standard deviation shall be 0,2 % or less. The within-laboratory reproducibility over long time intervals shall not exceed the repeatability by a factor of more than 3. 4.5 The design of the instrument shall be such that the total spectral transmittance is zero when the radiant flux incident on the specimen is zero. 4.6 The integrating sphere may be of any diameter as long as the total port area does not exceed 3,0 % of the internal area of the sphere. 4.7 The entrance and reference ports of the integrating sphere shall be circular and of the same size (see the note below). The … |
| 13 | 4.8 The photodetector shall be fitted with baffles to prevent light falling on it directly from the specimen. It shall also be shielded from light reflected from the internal surface of the sphere. 4.9 The surfaces of the interior of the integrating sphere and the baffles shall be of substantially equal luminous reflectance … 4.10 The apparatus shall be contained in a light-tight box. No radiant flux other than the sample and reference beams may enter the sphere. 4.11 The specimen holder shall be such as to hold the specimen rigidly in a plane normal ± 2° to the sample beam and as close as… 4.12 Errors caused by inter-reflections between the optics and the sample shall be minimized by tilting sensitive components or by applying an anti-reflection coating to them. 4.13 The apparatus shall allow the wavelength Æ to be varied over the range 380 nm u Æ u 780 nm in intervals of 5 nm. 4.14 By blocking each of the beams in turn, the radiant flux of each beam can be made equal to zero. The apparatus includes provision for recording the ratio 5 Test specimens 5.1 Specimens shall be cut from film, sheet or injection-moulded or compression-moulded mouldings. 5.2 Specimens shall be free of defects, dust, grease, adhesive from protecting materials, scratches and blemishes, and shall be free from visibly distinct internal voids and particles. 5.3 Specimens shall be large enough to cover the entrance port of the integrating sphere. 5.4 Three specimens shall be taken from each sample of a given material unless otherwise specified. 6 Conditioning 6.1 Prior to the test, condition the specimens in accordance with ISO 291, at 23 °C ± 2 °C and (50 ± 5) % relative humidity, for a length of time dependent on the specimen thickness and material such that the specimens reach thermal equilibrium. 6.2 Set up the test apparatus in an atmosphere maintained at 23 °C ± 2 °C and (50 ± 5) % relative humidity. 7 Procedure 7.1 Allow the apparatus sufficient time to reach thermal equilibrium before making any measurements. 7.2 Make the two readings described in Table 1. The specimen shall be mounted directly over the entrance port of the integrating sphere. Table 1 – Measurements 7.3 Repeat the readings fl1(Æ) and fl2(Æ) with the specimen in positions selected to determine uniformity. 7.4 Measure the thickness of the specimen in three places to an accuracy of 0,02 mm for sheet and 1 4m for film. |
| 14 | 7.5 Carry out the procedure on each of the three specimens in turn. 8 Expression of results 9 Precision 10 Test report a) all details necessary for identification of the test specimens and the source of the specimens; b) the thickness of the specimens (the average of the three measurements); c) the total luminous transmittance Ÿt for CIE standard illuminant D65 (the average of the three calculated results to the nearest 0,1 %). |
