Laboratory tests and field exposure tests were conducted on four coated fabrics to determine their suitability for storage under Torrid Zone climatic conditions for a period of three years. The performance under exposure of dry-back adhesive, which is used to fasten strips of membrane together, was also observed. In the laboratory, the tensile strength of each membrane was determined before, during, and after the storage period; the effects of weathering were also determined by measuring thicknesses and weighing samples of the membranes before and after the three-year storage period. In the field, membrane rolls with wooden and cardboard cores were placed in a rack and exposed to prevailing weather conditions with no protection from rain or sun. The membrane materials were inspected periodically, and photographs were taken to record important developments. Temperature, rainfall, and relative humidity data were also recorded throughout the storage period. Pertinent findings of the study are as follows:na. Cotton fabric coated with 20 oz per sq yd of vinyl coating (10 oz per sq yd on each side of fabric) withstood three years open storage in the. Torrid Zone, but cotton fabric with vinyl coating of 16 oz per sq yd did not.nb. Neoprene and Government rubber-styrene coatings applied to opposite sides of cotton fabric at the rate of 24 oz per sq yd on each side enabled the fabric to withstand three years open storage in the Torrid Zone satisfactorily.nc. Neoprene coatings of 8 oz per sq yd applied on each side of cotton fabric do not provide sufficient protection to enable the fabric to withstand three years open storage in the Torrid Zone.nd. Wooden cores are satisfactory for open storage of membranes, but cardboard cores are not.ne. The dry-back adhesive used in this study is unsatisfactory for open storage.nf. A mildew-resistance treatment used on the cotton knit and cotton duck fabrics was unsuccessful.
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