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Plastic Sheet, Acrylic, Heat Resistant
3. REQUIREMENTS q:alification. The acrylic sheets furnished under 3.1 this specification sh311 be products which are qualified for listing on the applicable qualified products list ac chg time set for opening of bids. (See 4.3 and 6.3.) Materials. The plastic sheet shall be an acrylic 3.2 type. The nanuEactucer is given a vide range in the selection Of mater— ials and unufacturing processes provided the furnished product is a transparent acrylic conforming to all the requirements of this specifi— cation and is suitable for the intended use (6. i) Color. Unless otherwise specified by the procuring 3..2.1 activity the naterial shall be colorless. Diænsions. Dimensions of sheets shall be as speci— 3.3 fied by applicable drawings or specifications. Unless otherwise speci— fled on the contract or order, a tolerance Of ±0.063 inch (1.6 m) will be allowed on length and width dinensions at 23±1 oc (73.5±2 OF) . Thickness. The actual thickness of the sheet at any point shall be within the tolerance specified in Table I. Thickness variations of sheets not included in table I shall not exceed the toler— ances for the next greater thickness listed in table I. Specific gravity. The specific gravity of the condi- 3.5 tioned material shall be I. 1920.01 when determined as specified in 4.6.1.
Water absorption. When determined in accordance with 3.6 4.6. I, che water absorption of che conditioned material shall not exceed values given in table I. the Rate of burning. tested as specified in 4.6. I, 3.7 rate of burning for a 0.500 inch (12.7 m) width of material shall the exceed the values given in table I. not Thermal exoansion. The coefficent of thermal expan- 3.8 'ion shall not exceed 0.00010 per degree centigrade (0.000055 per degree Fahrenheit) when tested in accordance with 4.6.2. Formability. Formability shall be determined as 3.9 specified in 4.6.3. Materials 0.500 inch (12.7 m) and less in thickness. 3.9.1 After heating in accordance with the manufacturer's suggested procedures, the material shall be suitable for forming into hemispheric shapes with the outside diamet•er of 10 inches (25.4 cm) and a draw of at least 4.5 inches (11.5 cm). Materials over 0.500 inch (12.7 m) in thickness. 3.9.2 When heated in accprdance with the instructions furnished by the manu- facturer, the sheets shall be quitable for bending into cylindrical forms of the radius given in table I without the appearance of crazing or other surface irregularities after accelerated weathering, Internal strain. The dimensional change after test— 3.10 ing in 4.6.4 shall not exceed I percent. Large values of dimensional change indicate the relief of high internal stress.