Document NZDQMe5wR72nZojR4G06V19y

Sprayed Mineral Fiber.Manufacturers Association, Inc. r. VCXKAtCM. hwMM U il< tiM Mnil Pratfwci* Ct*?Mr R. M. TOTH. Vic* U<> V ttmiir* Cwnr P.O. BOX 427. WESTFIELD, N. J. 07090 h. mTrrrop. saiuit -H.U. 1m.. . H. L. LCVIWe. TiiMvkM AikwiMir Crwmo * A. B. BtNCEX Eucvim Sicutur . *T Hr. William Tocha General Services Administration Public Building Service Specifications Branch - Roam 3033 19th and F Street, N.W. Washington, D* C. 20U05 Reference: GSA interim Guide Specification 22U-3A Mr. T. Reilly Standardization and Technical Services Division U. S. Naval Construction Battalion Center Davisville, _Rho.de^Island .028$li------ Reference: Federal Specification SS-S-IH, Subject: Air Erosion Test Method Gentlemen: The Sprayed Mineral Fiber Manufacturers Association has undertaken an extensive test program to evaluate the test method for air erosion or dusting of sprayed fiber as described in GSA Interim Guide Specification op Sprayed Fire Protection, 22U-3A, April 1966, paragraph OS Type XX. This work was done by the Kodaras Acoustical Laboratories, a recognised authority In the field of air-borne acoustics and vibration. The study indicated difficulty with the test method and its limits as follows: 1. When an impinging air velocity of 800 feet per minute is produced parallel to the specimen, there is no way to reduce the issuing velocity with any degree of accuracy down to 270 feet per minute. Therefore, the Association adopted a : test method using a constant velocity of 800 feet per minute .I nver the entire face of t*he specimen. 2. It was found that certain filter cloths are sufficiently hygroscopic to introduce a serious error in the final results. It was also found necessary to define the physical characteristics of both the black filter cloth and the filter used at the blower.end. -continued- Hr. Tocha, GSA Hr. Reilly, NCBC ------- '-- -2- February 7, 1968 3. Sufficient damage occurs to the test specimen during transportation and installation to necessitate a six hour purge prior to the 2U hour test period. ,, hm By conducting the test at the constant velocity . of 800 feet per minute on properly prepared specimens, an upper* limit of 0*025 grams per square feet of air erosion or dusting .. results* Ve therefore request GSA to revise this test method and limits, and suggest the following: Air erosion -not to exceed 0.025 grams per square foot when tested as specified. . Test shall be made In a suitable tight metal duct with a filter at the blower end having an efficiency of 95% in filter*' ing particles of 5 micron size or larger. The dust collecting black cloth shall be made of nylon fabric having a thread comb per inch of 102 for warp and 82.3 for filling, and calculated denier of 30 for both warp and filling. The cloth shall be dried to eonstant weight at 120F. before each weighing. Test specimen of the specified minimum density for the type of material proposed for use shall be placed in opening in side of duct so that face of sample and inside face of duct are in the same plane* r Air velocity shall be parallel to the face of the sample and maintained at a minimum of 600 feet per minute as determined by a standard vane type anemometer* The specimen shall be purged for six hours, after which it is tested for 2U. hours* Gain in weight of the black filter cloth or air ero sion for this test period shall not exceed 0.025 grams per square foot. Sincerely yours, SFRATED MINERAL FIBER MFRS. ASSN, INC. ras/ec ee: Hr. H. Levine Asbestospray Corp. 1060 Broad Street Newark, N.J. 07102 Mr. H. Wilson Baldwin-Ehret-Hill, Inc. 500 Breunig Avenue Trenton, N. J. 08602 P^3r. M. Lieff Smith It Xansler Co. lUlli E Linden Avenue Linden, N. J* 07036 Mr. J. F. 0'Rcurke U. S. Mineral Products Company Stanhope, N.` J. 07&7U Mr. A. E. Binger, Secretary Sprayed Mineral Fiber Kfrs. Assn, Inc. P. 0. Box L27 Westfield, N. J. 07090 ^