Overview
EN ISO 10545-18:2022 - Ceramic tiles, Part 18 - defines a laboratory test method to determine Light Reflectance Value (LRV) for ceramic tiles, including mosaic tiles. LRV is equivalent to the CIE tristimulus value Y (luminance factor) and is expressed as a percentage. The standard applies to solid‑coloured, multicoloured, non‑uniform shade, speckled, textured and flame‑effect tile surfaces with different finishes.
Key topics and requirements
- Scope and terms: Defines surface types (solid, multi‑coloured, non‑uniform shade, speckled, textured) and LRV as the CIE Y value.
- Principle: Measure visible light reflected by the tile across wavelengths weighted to human eye sensitivity to yield LRV.
- Instruments: Any reflectance spectrophotometer or tristimulus colorimeter capable of producing CIE X, Y, Z. Required performance: reproducibility ~1 ΔE (CIE Lab*) and repeatability σ = ±0.2 (five readings). Measurement area ≥ 8 mm diameter.
- Measurement conditions: Options include SCI (specular component included) with 2° or 10° observer and illuminants CIE D65, F2, A. Instruments must be calibrated per manufacturer guidance. Primary reference is barium sulfate; calibrated working standards (white glass, porcelain enamel, glazed tile) are acceptable.
- Specimen preparation:
- Solid tiles: at least three tiles, one specimen per tile.
- Multi‑coloured/non‑uniform/textured: select specimens representative of colour range; minimum numbers depend on tile area (see Table 1 in the standard). Mosaic: minimum 20 tesserae. Clean with a solvent (e.g., ethanol 96 %) and dry before testing.
- Wet testing allowed using grade 2 water (ISO 3696) with specimens kept wet for ≥5 minutes.
- Test procedure: Record CIE Y (LRV). For solid surfaces, take ≥4 readings per specimen positioned ~20 ± 5 mm from edges. For multi‑coloured surfaces, take readings per distinct colour area and calculate an area‑weighted average LRV.
Applications
- Product quality control and specification for tile manufacturers.
- Material selection for architects, interior designers, and lighting designers where surface reflectance influences daylighting, visual comfort and perceived brightness.
- Procurement and specification documents that require quantified LRV values for contrast, wayfinding, or aesthetic matching.
- Lab testing and certification bodies validating tile LRV claims.
Who uses this standard
- Tile manufacturers and R&D laboratories
- Test laboratories and certification bodies
- Architects, specifiers, and lighting consultants
- Interior designers and product compliance teams
Related standards
- Other parts of the ISO 10545 series (ceramic tile test methods) - consult the ISO catalogue for complementary test methods and requirements.
Keywords: EN ISO 10545-18:2022, LRV, Light Reflectance Value, ceramic tiles, mosaic tiles, CIE Y, spectrophotometer, SCI, CIE D65, tile testing, colour measurement.
