Asbestos compressed

Code designation, for gasket materials a = asbestos, white (compressed or woven) b = asbestos, blue (compressed or woven) c = asbestos (compressed and rubber-bonded) d = asbestos (woven and rubber-frictioned) e = CR-S or natural rubber 1 = Teflon... 

Gaskets in both dry gas and Hquid chlorine systems are made of mbberi2ed compressed asbestos. Eor wet chlorine gas, mbber or synthetic elastomers are acceptable. PTEE is resistant to both wet and dry chlorine gas and to Hquid chlorine up to 200°C. Tantalum, HasteUoy C, PTEE, PVDE, Monel, and nickel are recommended for membranes, mpture disks, and beUows. 

Energy Use and Conservation. A variety of materials are needed for high performance thermal insulation, particularly as components of nuclear reactors. Replacements for asbestos fibers are needed for components such as reactor core flooring, plumbing, and packaging. The fibers must be very resistant to high temperatures with outstanding dimensional stabiHty and resistance to compression. 

Compressed asbestos-rubber sheet To 700 Large number of combinations available properties vary widely depending on materials used. 

The leaks that lead to explosions in compressor houses are often not from a compressor but from other equipment, such as pipe joints. One such leak occurred because a spiral-wound gasket had been replaced by a compressed asbestos fiber one, probably as temporary measure, seven years earlier. Once installed, it was replaced by a similar one during subsequent maintenance [30]. 

The size and frequency of leaks can be reduced by using spiral-wound gaskets in place of compressed asbestos fiber ones. Screwed joints should not be used. 

GASKETS Xs" Thick, Compressed Asbestos Flat Ring Type. (JM 60 or Equal) 300°F and above, use Flexitallic CG. 

Compression and injection molding are used with amino resins to produce articles such as radio cabinets, buttons, and cover plates. Because melamine resins have lower water absorption and better chemical and heat resistance than urea resins, they are used to produce dinnerware and laminates used to cover furniture. Almost ah molded objects use fillers such as cellulose, asbestos, glass, wood flour, glass fiber and paper. The 1997 U.S. production of amino resins was 2.6 billion pounds. 

The textile fibers have a limited range of application. They may be used with hot or cold water, steam, oils and ammonia up to a maximum temperature of 100°C (212°F). Asbestos fiber is more versatile, can be used as compression packing material with hot water, super-heated steam, hot oils and gases up to 310°C (590°F). 

Flange face areas experience stagnant conditions. Additionally, some gasket materials, such as asbestos fiber, contain leachable chloride ions. This creates crevice and stress corrosion cracking problems on sealing surfaces. Where necessary, flange faces that are at risk can be overlaid with nickel-based alloys. Alternatively, compressed asbestos fiber gaskets shrouded in PTFE may be used. 

Compressed asbestos 250 General resistance to organic chemicals... 

Piston type aerosol system, 1 784 PIT (powder-in-tube) conductors, critical current density in, 23 833-834. See also PIT technique Pitch-based carbon fibers, 26 733-735 asbestos substitute, 3 314t compressive strength versus tensile modulus for, 26 742-743 Pitch-based fibers, 26 760 Pitch binders, 12 724-726 Pitchblende, 25 396-397 Pitch control, 10 304 Pitched blade turbine (PBT), 16 672 Pitches... 

US military requirements for crude asbestos are given in specification MIL-A-13651 and for asbestos sheet, compressed, MIL-A-7021A... 

This situation was inadvertently created when someone installed a compressed asbestos gasket (the nearly universal gasket for this chemical complex at that time) on a thermocouple flange in the vapor space. Specifications dictated a metallic nickel gasket, but the compressed asbestos was installed in error. 

As Compressed Asbestos Gaskets Are Phased Out, Other Leaks Will Occur... 

Compressed asbestos gaskets have been available for over 120 years. They are resistant to high temperatures and are inert to many alkalis, acids, oxygen, high temperature steam, petroleum products, and organics solvents. They are strong and relatively inexpensive. In many plants they have been the universal gasket material. 

It is disappointing, but the compressed asbestos gasket has no universal substitute. In many cases, it requires two, three, or more different, limited-application substitutes. Many substitute gaskets will cost between three and ten times higher than the compressed asbestos they replace. 

A petroleum refinery was in the process of phasing out compressed asbestos gaskets to conform to new U.S. laws. Asbestos gaskets had been used for years without any significant problems. During the conversion the company mistakenly assumed the nonasbestos substitute gasket would seal the same fluids as the asbestos products if the gaskets were used within the manufacturers temperature limitations. 

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