Fiberboards 2887 



Table 23-16. — Ejfect of relative humidity on moisture content, linear expansion, 



and thickness swell of six 'A-inch tempered commercial hardboards evaluated by 



Werren and McNatt (1975; see text footnote 5)'-^ 



At relative humidity of — (percent) 

 Hardboard type 



and statistic 30 64 80 90 97 



Percent 



Type A 



Moisture content 3.7 7.1 10.0 12.8 24.3 



Linear expansion .18 .32 .36 .45 .64 



Thickness swell 2.0 4.3 6.7 10.6 20.8 



Type C 



Moisture content 2.8 5.4 8.3 10.6 28.2 



Linear expansion 10 .20 .30 .33 .68 



Thickness swell 1.2 3.3 6.8 10.3 24.2 



Type E 



Moisture content 2.9 5.6 8.0 9.7 17.2 



Linear expansion 16 .32 .35 .48 .62 



Thickness swell 8 2.9 5.8 7.5 13.7 



Type G 



Moisture content 3.3 6.2 9. 1 1 1 .4 24. 1 



Linear expansion .18 .33 .39 .49 .67 



Thickness swell 8 3.3 6.3 9.2 21 .4 



Type J 



Moisture content 3.9 7.5 10.8 13.5 32.0 



Linear expansion .25 .45 .53 .63 .84 



Thickness swell 1.3 4.2 8.0 11.7 28.3 



Type L 



Moisture content 3.8 7.1 10.3 13.2 32.5 



Linear expansion .20 .35 .46 .52 .85 



Thickness swell 1 .7 3.8 7.9 11.7 30.6 



'Values expressed as a percent of ovendry value; each value is based on one specimen except those 

 at 97 percent relative humidity are the average for two specimens. 

 ^See table 23-11 for description of hardboards. 



