Document n9RoK8wjGVYQXYYRBjDk0dR7a

July 17, 1967 TO FROM: K. E. KEUPER, SAFETY SUPERINTENDENT CONSTRUCTION DIVISION ,. F. L. RUNT - W. H. ZANE ft, DESIGN DIVISION - POWER* In regard to the mineral wool preformed block insulation data I handed you on July 13, 1967. This material is available in block form only. Except for large lines, it cannot be used for insulation of pipe unless it is cut into lags and fabricated to fit the pipe. Since glass fiber will not cause asbestosis, it will be in corporated in project specifications. The objection to glass fiber by plant personnel is--the low resistance to abuse after installation; it is irritating to the skin; and is limited to services 70 to 350F. Therefore, we will continue with the conventional materials for temperatures above 350#F until a suitable replacement is developed. ' , ' The dust particle count being made at the various sites will help us determine the pipe insulation least hazardous to the health of the workmen. . Since mineral slag wool. Code 114, is an acceptable material and . is listed in the Engineering Standards, it will be included in the project specifications as an alternate to other acceptable blocks . (such as, calcium silicate, Unibestos, etc.) where bldtk insulation is required. . Sprayed Mineral Wool will replace the asbestos, spray material (Limpet) since the mineral wool contains 10J5 or less asbestos by volume as compared to Limpet having a 95$ or more asbestos fiber. Arrangements have been made for stress corrosion of S/S tests on mineral wool block. The mineral wool spray material has been tested and appears to be acceptable for use over S/S. WHZ/dp 094 DUP 0900842 SC-DP-01930