Acceleration of the weathering test －effects of changing water spray, temperature, and irradiance－

Abstract

Several accelerated weathering tests were conducted using uncoated sugi (Japanese cedar, Cryptomeria japonica D. Don) heartwood or sugi coated heartwood with penetrating or film-forming coating; test S (standard) based on JIS K 5600-7-7^:2008 (filtered xenon-arc radiation, method 1, cycle A, 38°C, irradiance 60 W/m²), tests W2 and W3 with 2-fold and 3-fold water spray, tests T48 and T58 performed at 48°C and 58°C, and tests C1 (3-fold water spray, 48°C, 1.75-fold irradiance) and C2 (3-fold water spray, 48°C, 2.5-fold irradiance). We found that C2 was the fastest among these tests, and we were able to estimate the changes in the wood during natural weathering in Tsukuba city by tilting 45° south facing 2.2 to 8.9 times faster compared with the S test.