Document ID: chunk:federal_register_of_legislation:F2015C00542:reg:254:p9
Version: federal_register_of_legislation:F2015C00542
Segment Type: reg
Provision Reference: reg 254 (pt 9/18)
Character Range: 122587–125678

source. No recirculation of the spray water or immersion of the test specimens in the water shall be permitted.

              6.4.1.3.9. The test specimens shall be rotated about the arc in order to provide uniform distribution of the light. All positions in the exposure apparatus shall be filled with test specimens or surrogates to ensure that a uniform temperature distribution is maintained. Test specimens shall be held in frames with backs exposed to the cabinet environment. However, reflections from cabinet walls shall not be permitted to strike the back surface of specimens. If necessary, samples may be backed to block such reflections so long as free circulation of air at the specimen surface is not impeded.

              6.4.1.3.10. The exposure apparatus shall be operated to provide continuous light and intermittent water spray in 2 h cycles. Each 2 h cycle shall be divided into periods during which the test specimens are exposed to light without water spray for 102 minutes and to light with water spray for 18 minutes.

              6.4.1.4. Evaluation

               After exposure, the test pieces may be cleaned, if necessary, by a practice recommended by their manufacturer to remove any residues present.

               Evaluate the exposed test pieces visually with respect to the following properties:

                  (a) Bubbles

                  (b) Colour

                  (c) Haze

                  (d) Noticeable decomposition

               Measure the luminous transmission of the exposed test pieces.

              6.4.1.5. Expression of results

               Report visual evaluations of exposed test pieces, comparing the appearance of each with that of the unexposed control.

               The regular light transmittance measured shall not differ from the original test on unexposed samples by more than 5 per cent and shall not fall below:

               70 per cent in the case of a windscreen and other glazing that is located in a position requisite for driving visibility.

  7.  Resistance-to-humidity test

              7.1. Procedure

               Keep three samples or three square test pieces of at least 300 mm x 300 mm in a vertical position for two weeks in a closed container in which the temperature is maintained at 50 °C ± 2 °C and the relative humidity at 95 ± 4 per cent. In the case of rigid plastic glazings and rigid plastic double glazed units, the number of samples shall be ten.

               The test pieces shall be prepared in such a way that:

                  (a) At least one edge of the test pieces coincides with an original edge of the glass pane,

                  (b) If several test pieces are tested at the same time, adequate spacing shall be provided between them.

               Precautions shall be taken to prevent condensate from the walls or ceiling of the test chamber from falling on the test pieces.

              7.2. Indices of difficulty of the secondary characteristics

                Colourless Tinted

               Colouring of interlayer 1 2

               The