Accelerated swelling of wood for rapid dimensional stability

Abstract

Dimensional stability of wood can be determined by measuring the total swelling percentage between 0% and FSP moisture content according to the ABNT NBR 7190 (Associação Brasileira de Normas Técnicas [ABNT], 1997). Wood dimensional variation by the moisture content modifications must influence both structural elements and connections into timber structures. The wood swelling procedure according to the Brazilian code for saturation of wood samples can take more than a month, but the use of autoclave devices may accelerate this activity, making easier the dimensional stability determination. This paper aims to investigate the possibility of accelerating the wood swelling activity using an autoclave device, considering the Brazilian code for thirteen Brazilian commercial wood species.  Contrast test for comparison between accelerated process (Stage 4 – 225 min. at 0.49 MPa pressure) and the conventional procedure for wood swelling resulted in p-value equal to 0.0730 and the average difference between groups about 1.1307% (varying between -0.0541 and 2.3156 with 95% confidence level). According to results, 225 min. at 0.49 MPa pressure provides an equivalent wood swelling compared to the conventional procedure, which can make faster the wood dimensional stability evaluation according to the ABNT NBR 7190 (ABNT, 1997).