Document k9ap1oRgxkXn5Jp5zga7kbw5q

i . Lester Divs. - Stds. Eng U'' May 22, 1972 tote SuSjcct Turbine Insulation General-Order Projects South Mr. J. D. Dickinson CC: . -A3-E------ Mr-H^-r-L-^-Shollenberger* , A3S_2 Dr. B.B.Seth f This is in reply to your letteror 5/8/Y2 requesting a list of all insulation materials used on our turbines containing motg asbestosJjian allowed by OSHA. In actuality, the limitation by OSHA is not to materials containing asbestos, but to the amount of airborne asbestos dust to which employees ?re exposed. OSHA states the 8 hour time weighted averay- o'rbcrnc concentration of asbestos dust shall not exceed 5 fibers per milliliter greater than 5 microns in length. Higher concentrations are allowed for shorter periods cf time. Various methods to meet these exposure limits are recommended, i.e./ enclosures, vacuum sweeping and exhaust ventilation. When these methods are not feasible or effective, respirators are prescribed. ' Our process specifications call for several asbestos or asbestos containing materials, as follows:- Material Process Spec. Applications 54251AH (Calcium silicate pipe covering - molded) 600433 Pt. 2 Pipe insulation up to 10 in. dia. incl Temp, to 1050 incl. 4660IBA (Calcium silicate plus diatomaceous earth pipe covering - molded) 600433 Pt.2 Pipe insulation up to 10 in. dia incl. Temp, over 1050F 46102BB (Calcium silicate block) 54Z5\AC. (600*30 IKiSOuiVToteQ i2E.il(0 J FlU-ne. 600433 Pt. 1 boo\{\ Pipe over 10 in. dia. or Small Turb. ' Cylinder Insulation Temp, to 1050F incl. T'J&SiJofc. tNiSuwvT Produced 3/93 28002840 Mr. J. D. Dickinson -2 - May 22, 1972 Material Process Spec, Applications 46601AA 600433 Pt. 1 (Hi-temp. cal. silicate or diatomaceous earth - block) . Pipe over 10 in. dia. orSmallTurb. cylinder insulation temp, over 1050 41511AP (12 oz./sq. yd. asbestos cloth) 600433 Pt. 2 &3 Pasted over pipexovering and gas turbines. 46110BA (asbestos finishing cement) 600433 Pt. 1, 2 & 3 Finishing coat over pipe & block insulation. 41511BF (2.5 Ib./sq. yd. 600359 Pt.l Blanket insulation covering for temperature to 600F incl. (To be asbestos cloth replaced by high temp, blanket using A'lZ^ AA. CA^ESToS (poolzc\ knitted wire.) isou\TioO JcikiT In the table preceding, the only materials containing large amounts of asbestos are the cloths and finishing cement. The calcium silicates have from 6 to 14% asbestos depending on the supplier and the diatomaceous earths are believed to contain about the same percentages. Since diatomaceous earth is only used at temperatures over 1050F (mostly on pipe) there is believed to be practically no application for this material. I am informed by insulation manufacturers that in the plants where calcium silicate is produced there is no problem in complying with OSHA asbestos dust requirements and that insulation contractors using reasonable precautions should have no problem meeting these requirements. If, however, due to customer demands there is no alternative but to supply an asbestos free insulation, the following may be substituted: Present Material Proposed Replacement and Supplier Asbestos Cloth (over pipe covering) Asbestos Cloth (blanket covering) Fiberglass cloth (Louis Halprin & Son, J. P . Stevens) Aluminum sheet Knitted Cloth ( ' (Presently used for hi-temp. blankets) Asbestos Finishing Cement k*j>6Ei>ToS Pi\Pr*2 oO|j Dl<MyciOiSii_ Mineral Wool Hydraulic Setting Cement Philip Carey - ivi`vV - one.48 Insulations Q.:i ... ^ Frglo-Picher - One Cote j Johns-Manville - 301jKccne - Super Powcrhons F6ei2dLAe*> CmXTH p*? Op U6MCA.O '0 mc Produced 3/93 ~ ~ 2800284 ; $. D. Dickinson -3 May 22, 1972 ** 7. Present Material Proposed Replacement and Supplier Calcium Silicate and Diafomaceous Earth Block and Pipe covering Expanded Perlite . Philip Carey - Careytemp Pabco in California is supposed to have an asbesi free insulation but markets only as far east as Chicago. While Careytemp can withstand temperatures up to 1500 F and has a good K factor there are several problems. It has rather low mechanical strength (compressive, tensile, abrasion resistance as compared to most calcium silicates. A long lead time (12 weeks at present) is required to obtain delivery due to Carey's limited facilities and heavy backlog. Johns - Manville and Owens - Corning are developing asbestos free calcium silicates which are expected to be available abput July at a premium price. Attached is a copy of a letter from Johns - Manville which should be of some interest on this subject. Lester Divisions - Standards Engrg. - Materials & Processes - M. Dorfman df ' Attachment Produced 3/93 28002842