Document QJ5RKorZ0v2b2pjMxoJVzVLnk

ASBESTOS GASKETS ARE GETTING FEWER By now, everyone i3 aware of the health hazard of breathing asbestos fibers. On November 4, 1983 GSHA far ther tightened the regulations on air borne asbestos fibers to reduce the statistical probability of asbestosis and lung cancer. The allowable level was cut fran 2 to 1/2 fiber over 0.0002 in. long per cubic centimeter of air. This level approaches the practical limit for detection and will undoubtedly cause companies which sup ply and process asbestos to get out of the business. Garlock, the largest U.S. manufacturer of packings and gas kets, discontinued its entire asbestos line at the end of 1982. Since asbestos fibers in compre 3ed 3heet gasketing material are loeke^ in by the rubber binder which makes up about 20} of most sheets, they cause no health hazard to the gasket user with normal handling and use. How ever, cleanup of flanges from which asbestos gaskets have been removed and handling of used, dried out gaskets will release asbestos fibers. There fore, from a safety as well as a legal standpoint, many Du Pont locations ban any asbestos-containing materials at the site. Aimed primarily at pipe insulation, woven tapes and loose col umn packings, the ban also includes packing, brake linings, and compressed asbestos gaskets. Design Division's Technical Services Section and the Gasket and Packings Standards Subcommittee have begun a transition program to phase out asbes tos gaskets over the next few years. They plan to: o Advise plant personnel of the tran sition with articles such as this one, and letters where needed. o Highlight asbestos-containing gas kets and packings by bold print1 of their Du Pont codes in Engineering Standards U2A and U1C, and in Spec ifications SU2A and SU1C. DL>-f W AC/ rooKt- FsrB. o Begin listing alternative gaskets along with the G-1, G-2 and G-40 gaskets in all new P-codes, and revising existing P-codes and spec ifications. o Remove references to all gaskets containing asbestos from the Du Pont codes after a period of time. Generally, the stocks of asbestos gas kets on the plants should be used up and not discarded at this time, sub ject to plant and department policy. Wherever possible, non-asbestos gas kets should be used by plant main tenance personnel. ^ The Standards now list four sheet gas ket oodes for 'non-asbestos" gaskets which have been specified a3 substi tutes for G-1, G-2 and G-40 (com pressed asbestos sheet) gaskets. The new non-asbestos codes are S-80, S-8l, S-82 and S-83. The differences are in the rubber used to bond the sheets: 0 S-80 SBR (Styrene butadiene rubber) 0 S-8l NBR (Nitrile butadiene rubber) 0 S-82 CR (Neoprene) t 0 S-83 EPDM (Ethylene-propylene terpolymer elastomer--Nordel ) In summary--Du Pont is phasing out asbestos in gaskets and packings. New non-asbestos codes have been esta blished and brands are approved for use. Plants should start using the new non-asbestos gaskets, but only those listed in SU2A. For further information contact , C. P. Shaw or W. M. Bounds, ENGG, ~Tr=8233 (366-3661). DUP 1001564 DU 050316