Document ID: chunk:federal_register_of_legislation:F2015C00542:reg:254:p4
Version: federal_register_of_legislation:F2015C00542
Segment Type: reg
Provision Reference: reg 254 (pt 4/18)
Character Range: 108626–111801

having a fixing hole 6.4           mm in diameter drilled in the center, if necessary.

              4.4. Procedure

               The abrasion test shall be carried out on that surface of the test piece which represents the outside face of the glazing when the latter is mounted on the vehicle and also on the inner face if of plastics material.

              4.4.1. Immediately before and after the abrasion, clean the test pieces in the following manner:

                  (a) Wipe with a linen cloth under clear running water,

                  (b) Rinse with distilled or demineralized water,

                  (c) Blow dry with oxygen or nitrogen,

                  (d) Remove possible traces of water by dabbing softly with a damp linen cloth. If necessary, dry by pressing lightly between two linen cloths.

               Any treatment with ultrasonic equipment shall be avoided. After cleaning, the test pieces shall be handled only by their edges and shall be stored to prevent damage to, or contamination of, their surfaces.

              4.4.2. Condition the test pieces for a minimum time of 48 hours at
              20 °C ± 5 °C and 60 ± 20 per cent relative humidity.

              4.4.3. Immediately place the test piece against the entrance port of the integrating sphere. The angle between the normal (perpendicular) to the surface of the test piece and the axis of the light beam shall not exceed 8°.

               Take four readings as indicated in the following table:

Reading  With test piece  With light-trap  With reflectance standard  Quantity represented
T1       No               No               Yes                        Incident light
T2       Yes              No               Yes                        Total light transmitted by test-piece
T3       No               Yes              No                         Light scattered by instrument
T4       Yes              Yes              No                         Light scattered by instrument and test piece

 Repeat readings for T1, T2, T3, and T4 with other specified positions of the test piece to determine uniformity.
               Calculate the total transmittance Tt = T2/T1.

               Calculate the total transmittance Td as follows:

               Calculate the percentage haze, or light, or both, scattered, as follows:

               Haze, or light, or both, scattered, =

               Measure the initial haze of the test piece at a minimum of four equally-spaced points in the unabraded area in accordance with the formula above. Average the results for each test piece. In lieu of the four measurements, an average value may be obtained by rotating the piece uniformly at 3 rev/sec or more.

               For each type of safety glazing, carry out three tests with the same load. Use the haze as a measure of the subsurface abrasion, after the test piece has been subjected to the abrasion test.

               Measure the light scattered by the abraded track at a minimum of four equally-spaced points along the track in accordance with the formula above. Average the results for each test piece. In lieu of the four measurements, an average value