Document 0gQoeywJg5qQK964L380Z8YvM

U. S. DEPARTMENT OF COMMERCE NATIONAL BUREAU OF STANDARDS mm ^noKAt. bwau oe stjucuhos WAftHMOTON is. o. c. 20234 January 27, 1964 RmcRTo rax Me Id. 07 ?fr. Frank M* Stumpf Vfcce President - Research Columbia Acoustics and Fireproofing Stanhope, New Jersey 07874 Dear Hr. Stumpf: Thank you for sending the samples of your products for preliminary tests using the Ro-Tap machine. We have started testa on the two Sound-Shield specimens. The first spec imen lost 0.0207 g in the first half hour and 0.8048 in the following 23-1/2 hours from an area of 50.27 sq. In. We have just started running the second specimen, on the same machine, and it appears from the first two or three measurements that it is going to behave, in about the same way. We took weighings of the residue at one-hour Intervals, and, although the rate of dusting had decreased toward the end of the test, material was still coming off at an average rate of about 0.01 grams per hour. This is a far cry from the maximum of 0.020 grams per 7.5 sq. ft. (or per one sq. ft., whichever it*s meant to be) mentioned in the CS-219.01 Guide Specification and leads me to suspect that the treatment afforded the specimens by the Ro-Tap may be too severe* We are going to have to exper iment with other test methods of differing severity, by the modification of the Ro-Tap and by the use of other devices. For this purpose X need some more samples of the ssme material rather than of the three different products, made as nearly alike as you csn make them. Instead of cutting the samples in circles and clamping them in a ring as X discussed with Mr. Schneider, we merely clamped them over the top. of a pan and collected what fell inside* This avoided the problem of sealing the edges. However, the 12-in. specimen wss too wide to go in the machine and we had to cut 2-1/2 in. off one side* I would appreciate it if you could supply me with six or eight more spec imens of Sound-Shield, sprayed at the same time and cured under the same conditions and cut to 9-1/2 in. square. 2 We will, in the neantioe, continue testa with the Heat-Shield and Blase-Shield specimens. Sincerely yours, cc: Harry Schneider Getty Browning Howard T. Aral, Materials Engineer Inorganic Building Materials Section Building Research Division