“…The hygroscopic behavior of fiberboard has been investigated many times (Kollmann and Mörath, 1934;Vorreiter, 1941;Lundgren, 1958, Kaila, 1968. Hysteresis loops for moisture content, length change and thickness change in complete relative humidity cycles 0 to 85 to 0% at 20°0 temperature are reproduced in Fig.…”