Industrial gaskets are classified into three structural families — non-metallic (compressed sheet, rubber, PTFE), semi-metallic (spiral wound, kammprofile, metal-jacketed), and metallic (ring-joint, corrugated, lens) — and each family is tied to a defined pressure-temperature envelope in ASME B16.20 for metallic/semi-metallic and ASME B16.21 for non-metallic flat gaskets [S6].
The base decision is flange class, media chemistry, and thermal cycle: a 150# flange in hot oil needs a different gasket than a 600# flange in hydrofluoric acid, and conflating the two is the most common cause of leak path failures. For deeper service-duty selection logic, see the Gasket Selection Map: Material, Flange Class, and Service Duty reference.
Non-Metallic Gaskets: Compressed Sheet, Rubber, PTFE
Compressed non-asbestos (CNA) fibre sheet, graphite laminate, PTFE, and elastomer sheet (Neoprene, EPDM, Nitrile, Silicone, Viton) cover the bulk of low-to-mid pressure service and are dimensioned to ASME B16.21 / EN 1514-1 flat-gasket geometry [S3]. Compressed fibre with aramid/inorganic filler typically rates to ~150°C continuous and ~40 bar; flexible graphite with stainless tang/inlayer pushes continuous service to ~650°C in steam and hydrocarbon service [S3]. PTFE sheet is the default for strong oxidizers and pharmaceutical skids because of its near-universal chemical resistance, but its cold-flow (creep) above ~10 bar at 100°C+ means soft PTFE alone is rarely used on raised-face flanges above Class 150 — expanded or filled PTFE is substituted [S3].
Elastomer gaskets (EPDM, Nitrile, Neoprene, Silicone, Viton/FKM) are cut from roll stock or moulded for face-seal and sanitary ferrule joints; typical hardness bands are 60–80 Shore A and temperature ceilings sit between -50°C (EPDM lower limit) and +200°C (Viton upper limit) for static service [S3]. For static-service O-ring geometry on the same flanges, the O-Ring Seal Suppliers 2026: Vendor Map, Spec Bands, and Sourcing Tiers reference covers overlap, hardness, and compound sourcing.
Semi-Metallic Gaskets: Spiral Wound, Kammprofile, Metal-Jacketed
Spiral-wound gaskets (SWG) are built by helically winding a V-section metal strip (usually 304/316 stainless, Monel, Inconel) with a non-metallic filler (graphite, PTFE, mica) and an inner/outer compression ring; EN 1514-2 and ASME B16.20 size them, and the standard fill materials run graphite to ~650°C, PTFE to ~260°C, mica to ~1000°C [S6][S8]. SWG is the default for ASME Class 150–600 raised-face and tongue-and-groove flanges in refinery, hydrocarbon, and high-temperature steam headers because the metal winding gives blow-out resistance while the filler conforms to flange face imperfections [S8].
Kammprofile (camprofile) gaskets use a solid metal core — typically 316L, Monel 400, or Inconel — with concentric grooves and a soft facing layer (graphite or PTFE) bonded to both faces; rated to ASME Class 300–600 in heat-exchanger and pressure-vessel manways, with a soft-layer temperature ceiling matching the filler (graphite ~650°C, PTFE ~260°C) [S6]. Metal-jacketed gaskets (MJ) wrap a soft filler with a metal envelope for heat-exchanger tube-sheet and handhole joints; standard formats in production catalogues include MJ, MJ-XT1, and MJ-XT2 variants for different bore/centering arrangements [S6].
Metallic Gaskets: Ring-Joint, Corrugated, Lens
Ring-joint gaskets (RJ) are solid metal rings — octagonal or oval cross-section per ASME B16.20 — machined from soft iron, low-carbon steel, 304/316 SS, Monel, or Inconel; they self-energise inside RTJ groove flanges and rate to ASME Class 600–2500 in hydrocarbon service, withstanding ~600°C on stainless and higher on Inconel/soft-iron variants [S6]. The non-asbestos, EPA-compliant equivalent for RTJ groove work does not exist — this is the one gasket type where metal-on-metal seating is mandatory.
Corrugated metal gaskets and lens gaskets extend metallic sealing to high-pressure heat-exchanger and valve bonnet joints; corrugated designs combine a corrugated stainless core with a soft facing for Class 150–600, while solid lens rings sit in conical seats for Class 900+ high-pressure/temperature isolation [S6]. These three metallic styles — RJ, corrugated, and lens — are the answer to any service above ~40 bar / 500°C where soft fillers would creep or oxidise.
Material Selection: Filler, Facing, and Fluid-Compatibility Map
Filler chemistry is the single largest leak driver: graphite swells in hot concentrated sulfuric acid above 60%, PTFE is attacked by molten alkali metals and fluorine, and EPDM fails in hydrocarbon service despite its steam compatibility [S3]. Viton/FKM is the default elastomer for hydrocarbons up to ~200°C; silicone covers -60°C to ~230°C food/pharma sanitary service; nitrile (NBR) handles oil and petroleum up to ~110°C; neoprene is the budget ozone/weathering choice for outdoor flange covers [S3]. The 3-criteria comparison below lines up the four filler families used inside spiral-wound and kammprofile gaskets.
Comparison (spiral-wound filler vs. criteria, from supplier and manufacturer data [S3][S6][S8]):
• Graphite filler: max continuous ~650°C; chemical resistance strong in hydrocarbons/steam, weak in hot concentrated H2SO4 and strong oxidizers; cost band low-to-mid; standard ASME B16.20 + EN 1514-2.
• PTFE filler: max continuous ~260°C; chemical resistance near-universal except molten alkali metals and fluorine; cost band mid; ASME B16.20, FDA-grade options for pharma.
• Mica filler: max continuous ~1000°C; chemical resistance high in oxidizing atmospheres; cost band high; ASME B16.20, used in place of asbestos in legacy hot-service.
• Non-asbestos fibre (CNA) filler: max continuous ~200°C; chemical resistance medium (water, oil, mild chemicals); cost band low; ASME B16.20 + ASME B16.21.
Fabrication Methods: Die-Cut, CNC, Spiral, Moulded
Custom industrial gaskets are produced by four primary routes: steel-rule die cutting for flat sheet (Neoprene, EPDM, CNA, PTFE, graphite) in high-volume runs; CNC knife cutting and waterjet for prototype and small-batch precision parts; hand cutting and lathe-cut rings for low-volume specials; and spiral-winding or moulding for SWG, kammprofile, and elastomer O-ring geometries [S3][S10]. OEM gasket fabricators typically run tolerance bands of ±0.1 mm on CNC-cut parts and ±0.25 mm on die-cut parts, with material certificates traceable to ASTM F104 (sheet) and ASME B16.20 (semi-metallic) on request [S10].
For OEMs and stockists, the Metal Stamping Part Types, Spec Bands and 2026 Industrial Use Map reference covers how stamped metal flanges and clamp components interface with soft-cut gaskets in HVAC and automotive assemblies.
Failure Modes, Limits, and Sourcing Signals
The five recurring gasket failures are: (1) creep/relaxation of soft fillers above their temperature ceiling, (2) chemical attack of filler or binder, (3) over-compression on low-stress flange classes, (4) under-load seating leading to blow-out during pressure transients, and (5) thermal cycling fatigue on SWG with non-graphite fillers above 400°C — all of which are addressable by re-deriving the gasket from fluid chemistry + flange class + peak service temperature rather than defaulting to a stock SKU [S3][S6][S8]. A practical verification step: a Class 150 raised-face flange at 10 bar saturated steam at 184°C is within CNA or graphite sheet limits, but the same geometry at 40 bar and 400°C is not — it has to move to spiral-wound with graphite filler, EN 1514-2 dimensioning [S6].
Two trackable signals for procurement teams: (a) demand for NSF-61 and FDA-grade rubber gaskets in food/pharma and water skids has lifted CNC waterjet throughput at US fabricators in 2026 [S10]; (b) spiral-wound supply from Chinese mills (Ningbo Kaxite and regional peers) remains the price floor for ASME B16.20 SWG, with standard 316+graphite rings on 4-week lead time and exotic Inconel-wound rings on 10–14 weeks [S8].
Spec-level background on the components involved: gasket, industrial adhesive, and industrial borescope.