Document nEbJg3QnreJJ49q5roQZRVnG

O'vens-Illinois Glass Company `miT nr olms' V. MAirerAornaia or Ci^kaa Pkoddcti General optxocs TOIiEDO February 12, 1943 Dr. I. U. Gardner, Saranac Laboratories, Saranac Lake, New York Dear Sir: You will recall an extensive investigation which you conducted for this company several years ago as to the air hygiene aspects of fiberglas. T7e have now in the pilot plant stage a new material regarding which we need some guidance as to what is indicated as necessary fraa that same standpoint. The material is a hydrous calcium silicate. Silica of 200 mesh per inch and finer is incorporated with calcium 4 hydroxide in a water suspension. After sufficient preliminary reaction to convert a portion of the reactants to a gelatinous form of such consistency as to suspend the remainder of the reactants and avoid settling, the material is poured into molds which are then placed in a steam cylinder similar to those cons only used in the manufacture of sand lime brick and subjected to 12S lbs. per square inch pressure of steam and its resultant temperature for approximately ten hours. During this time a crystallization occurs although the material is still wet when renoved from the cylinder. It is then dried and yields a porous mass which can be sawed like lumber. It is intended to use this material for certain interior structural uses, also as an industrial thermal insulating material for pipe, etc. The material contains no free calcium hydroxide but does contain a very slight amount of unreacted silica, presumably the larger particles of silica which have persisted while the available calcium hydroxide has been consumed in the formation of the hydrous calcium silicate. The following points merit consideration: 1. - Does the hydrous calcium silicate of itself constitute any air hazard from an air hygiene standpoint? 2. - Are the few residual particles of silica of such size and fre quency as to constitute a hazard? 3. - It should be considered from the standpoint of employees working in the plant where the material is made or where it may be sawed to desired dimensions, and also considered from the standpoint of applicators or erectors at the point of use. ** Owens-Illinois Class Company )HC M* rs- Dr. L. U. Gardner, Saranac Lake, Kew York. February 12, 1943 We are forwarding to you by nail two camples - one which will repre sent the material which collects in our dust-collecting system, and the other represents material, presumably finer, which has settled from the atmosphere in a finishing roam where cutting of the material is done. We would like to have your opinion tentatively as to the situation for our present needs and your suggestion as to a suitably comprehensive program to permit a final determination of its status. The writer recalls very pleasantly having lunch with you and Ur. Walters at Baltimore a few years ago during a meeting of the American Ceramic Society. Very truly yours. U. E. Bowes jg cc - Ur. A. C. Hirth Ur. U. U. Olander Ur. E. E. Renn Ur. David Innes - Berlin Director of Research