- Author
- Jessup, D. A. | Weber, C. G. | Weissberg, S. G.
- Title
- Stability of Fiber Building Boards as Determined by Accelerated Aging.
- Coporate
- National Bureau of Standards, Washington, DC
- Report
- BMS 50, May 13, 1940, 8 p.
- Keywords
- building boards | fibers | stability | aging (materials) | exposure | tests | moisture content | humidity | thermal conductivity
- Abstract
- Fiber building boards were aged by exposure to cycles of wetting, freezing, drying, and baking and to outdoor weathering. The boards were tested before and after aging to determine the changes produced, and judgment of stability was based on the changes. The properties tested were weight, thickness, expansivity, thermal conductivity, flexural properties, nail-holding strength, water absorption, ash, rosin, and permeability to air and water. Data were obtained on the relationship between the moisture contents of the boards and the relative humidity of the surrounding air and on the resistance of the boards to rot-producing fungi. In general, the retention of the most essential properties - namely, thermal conductivity and strength - was excellent. Furthermore, the boards did not support the growth of rot-producing fungi except at relative humidities above 85 percent. At the high humidities, the fiber boards are subject to mold growth, but it was shown that the growth can be prevented, or at least appreciably retardced, by use of fungicides.