Non-asbestos gaskets have fully replaced asbestos gaskets for decades as studies demonstrated the risks (for human health) associated with the production, use, and disposal of asbestos materials. The ASME B16.21 specification covers non-asbestos sheet gaskets (types, sheet materials, dimensions, dimensional tolerances, and marking requirements).
The two main types of non-asbestos gaskets are the “full face” (FF) for FF flanges and the “flat ring” type for raised face flanges (RF) .
Non-asbestos gaskets are the simplest type of gasket for flanges and are produced by cutting graphite, organic or inorganic non asbestos sheets into shape (generally, with water jet cutting machines). This type of gaskets for flanges suits low pressure, low temperature, and non-critical piping and plumbing applications.
Learn about the 5 key flange gaskets types (used in the oil and gas industry): non-asbestos gaskets full and raised face (used for low-pressure, low-temperature and non-critical applications), spiral wound gaskets (for higher temperature and pressure oil and gas applications), Ring joint gaskets style R, RX, BX (for RTJ flange faces), Kammprofile and Jacketed gaskets. The article describes the scope of each type of gasket, the dimensions to ASME B16.20 and ASME B16.21, the materials and give some indications to select the right gasket for piping applications.
The terms, “flat-cut gaskets”, “die-cut gaskets”, “compressed sheet gaskets” and “asbestos-free gaskets” are synonyms to define this low-end family of flange gaskets.
To select the right material for non-asbestos gaskets , multiple factors shall be considered: fluid, temperature, pressure, fugitive emissions laws, and mechanical issues.
The most common materials used to manufacture compressed fiber gaskets are aramid fibers (Kevlar), glass fibers, elastomers, Teflon (PTFE), graphite, neoprene mixed with various binder materials (the most common binder is NBR, i.e. Buna-N):
For more information ring joint gasket, please get in touch with us!