Document mbM1VEz2b4ybymGvxr63dyXd

M, 1970 4. ml SUp SB|lMerlBg Cmter Coda Ut pdtavills, Maryland . Attention: Me. inoa Bifnbwi **tleans: V After ntnelvr tasting at one H. K. Foetar Coaptny, Zac.. Ibtnrii MtUiac, Charlotte, berth CkoIIm plant Cor netkorfa to control airborne- tfnt released in tha handling* of Mbattoe elottt, mm propose that federal epeeif ication SS-C-4C6e he aandM asfolloMts action 1.2.1. Fern i-Cloth - Add (Txuted) To the following, grade*? tada 8.6. - 60 Farcent asbestos, blue stripe. Treated Ctade ill >90 " " rad stripe, ftttted beds AM - " ** green stripe.Treated Grade AM 75 " " plain weasc. 4t* insertion, no l.t Mftetoa dost and treatnant there of - the wtsc olskla treat* anht nhan applied to aateetos cloth (ell otylat) will ntet airborne hat hjr n Mniatss of fifty (50| percent when tested in accordsnee nith Paragraph 4.4.1.8. Varegrapfc 4.4.1.'2 Asbettoe Content - change to read as follens; Tha aebaato* content shell he determined in accordance otth the netfaof specifled is ASTH P 1916. after reaovel of the utter eolnhle treetaant sXida bp an appropriate method sash ae boiling in enter. 4.4.1.S Airborne Asbee toe fast - The airborne asbestos dust shell bn Atteroinsd by the vibrator tester antbod in accordance nfctb the fallowing procedure. Continued Ma*l Ships Engineering Center -2- Juua 16. 1970 *.4.1.8.1 SCOPS; ~ The test procedure is based upon a modification of the machine described for the vibration teat in HUitarg Specification MIL-I-159Q1C - Insulation Felt. Thermal, Asbestos Fiber. The vibrator is contained within an; enclosed chamber which has a volume of eight cubic feet ' <2* z 2* x 2*). The sample to be tested is oscillated at 7oo cycles per minute through a vertical meveoeet of one-ha If inch. Oust sampling is made by the ttifet Im pinger Method with the Impinger mounted inside the-enclosed chamber while the sample is vibrated. Air ia pulled through the Impinger by a MSA Permissible Air Samplimg Iw^. The pump ie connected to the Impinger inside the boa by a length of rubber tubing which extends from aa opening in the box. The sampling pump is calibrated to have a flour rate of one tenth cubic foot of air par minute. Sampling time is thirty minutes after vrtiich the Impinger end the - sample arc removed. 4.4.1.8.2 SAMPLING; - Obtain three samples from the test fabric. Each test . specimen shell be twelve (12) inches. Caution oust bm exercised to avoid particle loss due to excessive handling. 4.4.1.0.5 EQUIPMENT; Vibrator Ifcstcr Stop Watch MSA Samp ling Pump. calibrated to a flow rate of 0.1 cubic feet per minute. Midget Xmpingars Sampling reagent (distilled water, iaopropy*.alcohol, etc.) Hiscroacope equipped with Uhipple Disk reticle Slides Vacuum cleaner 4.4.1.8.4 PROCEDURE; Haunt teat specimen on sample holder with filling yarns in a horizontal position. Place Midget Impinger in special clamp mounted inside test chamber and connect with rubber hose to sampling puxp out side. Fasten door securely end start vibrator along with sampling pump- and atop watch. Continued. . M Ships SnglnMring Canter --3- i*. 1970 *.*.!..* pflocnogs - carniwasp Chock aanple for thirty uinuton. tuia off tfdpMi ahl ' remove laplsflit. Smooi Mtplt sad clcaa toot chinboc thoroughly with * vacuus dMMt prior to mounting now eheple. *.*.1.8.3 grstOATIfm OP TS3T 0A7A:* Sampling avaluation is and* after the dost paxticlao have been counted fra aach bpingar used dozing the tuttlig. This proeodure is heat perforand by someone that in ex perienced in the Midget Isspiogsr Method of coasting date particlea. . The average amber of dust particles found is five ciianftif is used in the following formulatiom: 4*vg. count - blau) a * x 1000 x voluoe in al. of hgigt reagent laping? rating z saqpliag tine in ainotes x 1.000,008 the answer obtained fcos the fernalatiea in expensed is a^Hioa pnrtidoa per cubic foot (IffCF). after tbs dh*& particle* have been calculated foe all samples, eltalt as average fro* tho throe tasplcr that were takes fees each fabric, this average can now be osod os * cooperiaea to shoo the aaooat of dust redaction or dust increase frees one group of samples to another. * Method ftor determining Asbestos Oust Concentration Approved by the asbestos Textile Institute October 8, 1985.. JWC:etg ec; FtMi willisas J. tf. Bchrrd Director of E.8 9.