O-Ring & Seals — validation & limitations

What it calculates

• 202 O-ring sizes by SAE AS568 dash number, each with a nominal ID, cross-section and tolerance — the tool names an orderable dash number. Covers the 000, 100, 200 and 300 series (1.78 / 2.62 / 3.53 / 5.33 mm wire); the 400 series (6.99 mm) is not included.
• Automatic size selection that picks the cross-section family from your groove depth, then the nearest inside diameter to the groove root
• Compression (squeeze) and diametral stretch check for static and dynamic applications
• Gland fill percentage and recommended groove dimensions (depth H and width W) by application type
• Pressure-dependent clearance-gap (extrusion) check — the maximum gap tightens from 0.08 mm at 50 bar to 0.01 mm at 300 bar
• Extrusion threshold check with single-, double- or no-back-up-ring recommendation by elastomer and pressure
• Material suitability across NBR, FKM, EPDM, PTFE, Silicone and HNBR — temperature range check (fluid compatibility is listed for reference only, not checked)
• Groove design reference table across all four application types: static face, static bore, dynamic reciprocating and dynamic rotary
• Gasket bolt-load calculator to ASME VIII Div. 1 Appendix 2 (seating and operating bolt-load, effective seating width)

Related standards — reference only, not implemented

• ISO 3601reference only — O-ring sizing, compression squeeze, gland fill, extrusion check and back-up ring selection for static and dynamic applications. Note the size list uses SAE AS568 designations, NOT the ISO 3601-1 metric series, and the squeeze/fill target bands are gland-design practice badged as estimates — this tool does not certify conformance to ISO 3601.

Validation evidence — independent reference cases (1)

Each case runs the tool's engine on a worked example whose values come from a published source or a hand derivation from the cited equations, and an automated regression test asserts the engine against those values within the stated tolerance. "Conservative" means the engine is known to sit on the safe side of the reference and the test asserts that side. Sources are cited; their text is not reproduced.

• Wide-gasket bolt load and bolt-area margin

  Agrees

  Source: ASME BPVC Section VIII Division 1, Mandatory Appendix 2, §2-5 and Tables 2-5.1, 2-5.2; ISO 724 thread minor diameter

  Inputs: D_go 200, D_gi 150 mm, soft aluminum, P 3.0 MPa, 12 x M20, S_b 172 MPa

  Quantity	Reference value	Tolerance
  effective seating width b (mm)	8.90926	0.1 % relative
  seating load W_m2 (kN)	309.3838	0.1 % relative
  required bolt area (mm2)	1798.74	0.1 % relative
  bolt-area margin	1.50231	0.1 % relative

  Conservative simplification: The engine carries y rounded to 60.7 MPa and the SI constant 2.52 for b, which differ from the hand values by 0.04 % and 0.003 %.

  tests/golden/REF-seals-gasket-wide.golden.test.ts

Limitations

Conservative simplifications

• Wide-gasket bolt load and bolt-area margin — The engine carries y rounded to 60.7 MPa and the SI constant 2.52 for b, which differ from the hand values by 0.04 % and 0.003 %.

Not checked by this tool

• Chemical / media compatibility of the elastomer — Only the temperature range is screened; check the seal maker's chemical resistance chart
• Dynamic wear and service life of the seal — Not evaluated; use the seal maker's life data for the duty
• Rapid gas decompression in gas service — Not assessed; specify a decompression-rated compound (ISO 23936-2 / NORSOK M-710)
• Shaft run-out and offset for lip seals — Not checked; compare with the lip-seal maker's dynamic run-out and offset limits
• Gasket flange design: flange moments, hub and ring stresses — Bolt loads only; complete the ASME VIII Appendix 2 flange stress checks or use EN 1591-1
• Gasket leak-tightness class — m and y factors only; for emission-critical joints use EN 1591-1 tightness classes