A technical guide to opal diffuser sheets for LED lighting — what makes a diffuser “opal”, how transmittance and haze trade off across diffusion grades, PMMA vs polycarbonate vs polystyrene options, opal vs prismatic optics, and practical guidance on thickness, fabrication and applications.
A K12 prismatic sheet is a large-facet optical diffuser used in LED troffers, high-bay luminaires, and recessed ceiling panels. Known by many names — P12, Pattern 12, PL-21, Prismatic Louvre Panel, Troffer Lens Panel — this guide explains the geometry, how the codes relate, which material to choose, and what specs to check before sourcing.
A complete technical comparison of PMMA, polycarbonate (PC), and polystyrene (PS) for LED diffusers and optical sheets. Covers optical transmittance, impact resistance, fire ratings, UV stability, thermal behaviour, and application-by-application guidance to help engineers and buyers specify the right material first time.
Both Polycarbonate and Polystyrene prismatic diffusers can achieve TP(a) rigid fire classification under UK Building Regulations Approved Document B. See our SGS-certified test results and learn what TP(a) means when specifying UGR<19 lighting for commercial, educational, and public spaces.