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.
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.
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 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).
NON-ASBESTOS GASKET MATERIALS
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):
- Aramid NBR binder
- carbon graphite reinforced
- glass reinforced (steam service gasket)
- PTFE bi-axially oriented (silica filler)
- SBR (styrene-butadiene)
- CR-chloroprene (Neoprene)
- EPDM gasket (ethylene propylene)
- fluorocarbon (Viton)
- BUNA-n-rubber (nitrile, NBR gasket)
- chlorosulfonated polyethylene (Hypalon gasket)
- aramid + SBR binder (premium type gasket)
- graphite + ss316/316l insert
- PTFE biaxially oriented (with hollow glass microsphere) blue
- PTFE biaxially oriented (pigment-free)-gray
- expanded PTFE gasket
- PTFE joint sealant
- PTFE envelope slit type
- PTFE envelope milled type
- PTFE envelope formed type
- MICA sheet
- ceramic fiber