BS 17317 pdf free download

BS 17317-2020 pdf free download.Resilient, textile, laminate and modular mechanical locked floor coverings — Light reflectance value (LRV) of a flooring surface.
6 Apparatus Sphere-type spectrophotometer, capable of measuring LRV to a precision compatible with the reproducibility of 1 unit ΔE CIE L*a*b*. The instrument shall have a spectral range capable of measuring the LRV of a specimen at 16 wavelength points spaced at 20 nm wavelength intervals from 400 nm across the visible spectrum. The instrument shall be capable of measuring a 10° visual field (Y 10 or the 10° standard colorimetric observer). The instrument shall be designed such that a correctly positioned specimen is irradiated uniformly from all directions within the hemisphere bounded by its plane. The instrument aperture shall be delimited by the area over which the receiver senses flux rather than the area illuminated. Radiation reflected at the sampling aperture shall be evaluated uniformly at all directions within 5° of the axis of the collection beam. The axis of the reflected beam shall be 8° off the normal of the centre of the specimen plane in which the specimen is placed during measurements. The reduction in sphere efficiency due to specimen absorption shall be corrected to produce a linear output. Where a single beam integrating sphere is used, the treatment of the outputs needs to include a correction for the reduction in sphere efficiency caused by specimen absorption. Without such a correction the instrument will give a nonlinear output. Standard illuminant, CIE D65. This is generally representative of a phase of daylight with a correlated colour temperature of approximately 6 500 K. Measurement area, of at least 7 mm diameter compatible with that provided by commercially available spectrophotometers. 7 Test specimens 7.1 General Three specimens shall be selected as being representative of the surface for the test. Where there is variability in the colour of the three specimens, then nine specimens shall be selected, see below note to decide on. NOTE Variability in the colour of the three specimens will be deemed to have occurred where the difference between the highest and lowest LRV is ≥ 4. 7.2 Preparations of test specimens The surface of the specimens shall be clean and representative of the surface of the material. There shall be no pressure marks on, or foreign matter attached to, the surface of the specimens to be tested. Cut pile carpets (textile floor coverings) shall be brushed with a clothing brush in the direction of the natural pile lay before measurement. Where there is concern with regard to the stability of the colour and appearance of a specimen over the period of the test, the specimen shall not be measured. Specimens shall be large enough to extend beyond the measurement area of the instrument. For specimens which do not have a patterned or textured surface a specimen size of 150 mm × 150 mm shall be used.
Where patterns on surfaces cannot be fully represented by a specimen of this size then a specimen size of 450 mm × 450 mm shall be used and the LRV measurements shall be taken at the 9 centre points of each of the 150 mm × 150 mm grid, set out to place the measurement point at the centre of equal areas of the specimen surface.
8 Test procedure
8.1 Calibration procedure
Switch on the instrument and allow sufficient time for stabilization in accordance with the manufacturer’s recommendations.
Where applicable, ensure that the instrument has the capacity to undertake the required measurements. The instrument shall be calibrated in accordance with the manufacturer’s recommendations.BS 17317 pdf download.