AS 1428.1-2009 PWD Code.pdf

AS 1428.1—2009                                          104



       (d)    If either building element is highly coloured, correct any significant deviation
              from the CIE V (λ) function by measuring the luminance of a white plate (L a)
              directly and then through a filter (L b) with nominally the same chromaticity as
              the building element and known luminous transmittance (τ ) = the correction
              factor (F) is defined as follows:
                             La
                        F=      ×τ
                             Lb
       (e)    When calculating the contrast between the building element use either one of
              the appropriate following equations:
                                              L2 − L1
                        If L2 > L1 then C =
                                                L2

                                              L1 − L2
                        If L1 > L2 then C =
                                                 L1
              Compliance is established using C as appropriate.
       (f)    To carry out wet measurements take measurements in at least 5 locations (on
              each building element) or on five units of the product (such as samples where
              5 units are available). Where the surface does not appear (visually) to be
              uniformly coloured, a minimum of 10 measurements have to be taken. Record
              the luminance reflectance (L value) for each individual dry measurement that
              is made. The luminance reflectance (L value) of the CIE 1964 colour system is
              recognized in AS/NZS 1580.601.2.
       (g)    Unless wet measurements are deemed to be inappropriate, wet the surface of
              the product and ensure that the surface remains wet (such that water ponds
              on the surface) for a minimum of 5 min. Take measurements as in Step (c) as
              soon as possible after removing any unabsorbed water from the surface with a
              cloth or sponge that does not leave any solid residue. Record the luminous
              reflectance (Y value) for each individual wet measurement that is taken.
              Determine the mean dry luminous reflectance (Ld) and the mean wet luminous
              reflectance (L aw ).
              NOTES:
              1   The use of standardized illumination conditions when making photometer
                  measurements could enable manufacturers to publish luminous reflectance values
                  that are consistent with those obtained using this Appendix.
              2   For standard colours, see AS 2700.
       B5.4 Report
       The following has to be reported:
       (a)    Full description of the building elements with product details where known.
       (b)    The instrument being a luminance meter with a 1° measurement area
              corrected to approximate the CIE 1931 Standard Observer.
       (c)    The location of the sample, if on-site.
       (d)    The location of the sample of the measurements on the first building element.
       (e)    A description of the light source(s) illuminating the sample, including type,
              e.g., fluorescent tube, incandescent, high pressure sodium discharge, metal
              halide, and colour (in general terms).
       (f)    The mean luminance reflectance of the second building element to the first
              building element under the conditions set out in Paragraph B5.3.

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