Documented dimensions required — geometry only
Annular Gasket Geometry
Calculate nominal geometry from an identified gasket inner diameter,outer diameter and uncompressed thickness. No standard size,material or bolt load is inferred.
Nominal geometric results
Ideal annulus formulas
For documented inner diameter Di,outer diameter Do and uncompressed nominal thickness t,the radial width is b=(Do−Di)/2 and mean diameter is G=(Do+Di)/2. Subtracting the two circle areas gives the gross nominal plan area:
Inner,outer and mean circumferences are πDi,πDo and πG. The ideal rectangular radial section is b·t and the solid annular-envelope volume is A·t. For a spiral-wound,serrated,porous,composite or otherwise non-solid gasket,this envelope volume is not the actual constituent material volume or mass.
Not an effective seating area
A is only the area of the nominal planar annulus. It is not automatically the effective gasket reaction area and must not be multiplied by an assumed y value to claim seating load. Compression behaviour,flange facing,standard-specific effective width,service conditions,qualified gasket parameters and the full joint method determine design quantities.
Standards context — tables are not implemented
ASME B16.20—2023 is the current metallic-gasket edition identified by ASME and covers standardized metallic gasket constructions within its scope. ASME B16.21—2021 covers types,sizes,materials,dimensions,tolerances and markings for nonmetallic flat gaskets suitable for referenced flange standards. Their licensed dimensional tables are not reproduced or inferred here.
ASME B16.5—2025 covers ratings,materials,dimensions,tolerances,marking and testing for its specified flanges;flange bolting data must not be silently treated as a B16.20 gasket table. ASME PCC-1—2022 provides pressure-boundary bolted-joint assembly guidance within its scope;this elementary geometry is not a PCC-1 load calculation.
All selected-unit dimensions remain in that unit. NIST defines1in exactly as25.4mm,so area scales by25.4² and volume by25.4³ between equivalent inch/mm inputs. Sources checked12July2026. No closed clause,table,standard size,m/y factor or material limit is asserted.
Selection warning: verify flange standard/edition,NPS,class,facing,gasket construction,dimensions,tolerances,materials,marking,manufacturer data,fluid,temperature,pressure and applicable law. A geometric match alone does not establish suitability.
Nikolai Shelkovenko
Nikolai Shelkovenko is a vibration analysis engineer and the founder and CEO of Vibromera. For more than 15 years he has balanced rotating equipment in the field rather than on a test bench: mulchers, industrial fans, crushers, centrifuges, shafts and spindles. That work is what the Balanset instruments grew out of — they were designed as a tool a specialist can carry to the machine and use alone, on site, not as laboratory equipment. Vibromera was founded in 2017 and has been based in Porto, Portugal, since 2023. Development, assembly and support of the Balanset line all happen here. The flagship instrument is the Balanset-1A, a portable analyser for single- and two-plane balancing and for vibration diagnostics. Nikolai is personally involved in customer support, in working through difficult balancing cases and in the development of the software. He works with customers worldwide, in any language.
