Document 5vdq30ObM9jEzrN9xa2pk6EJ

735 August 3 1961 Mr. B. 3wytnyk Underwriters' Laboratories Ino. P. 0. Box 247 Northbrook, Illinois He: File No. R4491 & 61K178 Dear Mr. Swytnyk: The formulation of the fireproofing plaster to be used on the floor & celling construction Is as follows: 3.67 cu. ft. of perlite (8 to 9i lbs. per cu. ft.) 43 lbs. calcined gypsum 14 lbs. 7D3 asbestos 5 lbs. High early strength cement 0.2 lbs. Ultrawet D3 0.15 to 0.2 lbs. commercial retarder The physical characteristics of the material will be about as follows: Water to plaster ratio - 130-140 parts water to 100 parts plaster Setting time - 12 to 16 hours Wet density - 39 to 44 lbs. Pr cu. ft. Dry density - 28-32 lbs. per cu. ft. Procedure for making testa: 1. Setting time - Add 135 co water to a quart mixing vessel, add 100 gma plaster, soak for 30 seconds and stir for 30 seoonds. Place mixed plaster Inside a brass or similar ring, 3A inches^and about 4 inches in diameter) the ring resting on a clean glass plate. Strike off the plaster level with the top of the ring, and determine the setting time with a l/4 lb. Oillmore needle) set being called when the needle falls to penetrate to the shoulder. Test eaoh hour and determine set to the nearest hour. 2* , Vet density - Add 135 oe water to a quart mixing bowl, soak /' 30 secone and mix for 2 minutes with a spatula (1" x 4" blade), / - u,ei:hg ab< /- / \ oXVlmowp />- 100 strokes per minute. Place plaster in a vessel me, weigh, and determine wedensity. \/ ft C ft iL f C--V . SGP 0019047 B. Svytnyk 2 - August 3, 1961 3, Dry density - Add 135 oo water to a quart container, add 1 oa of ootyi alcohol, and 100 gas of the plaster* Soak 30 aaaonds and stir for 2 ndnutas aa In #2, plaea In 2 inch euba melds, puddling to remove air voids aa oovered In ASTM G26 for waking oompraaaira strength* 3tora In humidity oabinat until set uaually 2k bourn la sufflolentf than remove and dry as In C26 and datarmlna dry density* Tha oatyl alcohol la a dafoaning agent and permits dataralnation of tha dry density very alnllar to that of tha plaatar after It la applied by maana of a plastering machine sprayer* Ve would suggest you hare your Inspector be la Orand Rapids early in tha week of August 21, to observe running tha material to be used in the test. Tour lnapeetor will, of oeurse, advise Up* Mesa at our Grand Rapids plant whan ha will be there* You have sat up label service on similar produets made by our ca^atltore, and we oaa be guided in part, at least, by the types of taste required in their inspeetlon services* We shall be pleased te hear any suggestions you ears to make* Tory truly yours, HB3TVALL OTPSUM COMPART CGS/md 0* G* Shuttleworth * Chief Ohemist CCi Mr. J. B* Mess - Grand Rapids Will you please make up a trial charge as follows and sand me a bag as soon as convenient so that ve can- teat .before tha U.L. inspector arrives. Use plain valve bags. If available, otherwise sack in Lite Acoustical bags, marking plainly what it is. Batch; 20 eu* ft. perlite (8 to 9$ lb.) 262. lbs. stucco GR-52 is. 7D3 asbestos 5 oz. Lujmite Cement - Universal Atlas - or equal IQ ozVGfttravet D3 oz. TeJarder CHarge rff H 4 D #222. Hold balance of charge until ve advise / i. /L^ SGP 0019048