Spiral Wound Gasket
Product Description
Metal-wound gasket with alternating metallic and filler layers, providing excellent sealing under high pressure and high temperature with superior recovery characteristics.
Available in all standard sizes and pressure classes, with custom dimensions per drawing. Each gasket is marked per standard requirements for full traceability.
Applications
Spiral wound gaskets are the industry standard semi-metallic seal for high-pressure, high-temperature flanged joints in refineries, power plants, and petrochemical facilities. The alternating V-shaped metal winding and soft filler (flexible graphite or PTFE) provide excellent spring-back under cyclic thermal conditions, sealing reliably from -200°C up to 600°C in steam and non-oxidizing service, and pressures up to Class 2500.
Typical installations include steam turbine piping, boiler main steam connections, refinery catalytic reformer and hydrocracker flanges, hot oil thermal transfer systems, and compressor discharge piping. The controlled density design prevents gasket blowout under pressure and compensates for flange rotation and bolt relaxation.
Inner and outer rings are available for centering and anti-ejection in wide-face flanges. Standard sizes cover NPS 1/2″ through 24″ per ASME B16.5 and up to 60″ per B16.47 large-diameter flanges. SS316L winding with graphite filler handles most refinery services; PTFE filler is used for corrosive chemical duty.
Quality Assurance & Certification
Each spiral wound gasket is manufactured to ASME B16.20-2023 dimensional and material specifications, with winding thickness, density, and compressibility measured per standard tables. We supply EN 10204 3.1 certificates for metal winding material (chemistry and hardness) and filler material compliance data.
Dimensional checks confirm inner diameter, outer diameter, and thickness against ASME B16.20 tables for each class and size. Marking on the outer ring identifies size, class, winding material, filler type, and manufacturer per standard requirements. Third-party inspection by SGS, BV, or TUV is available for power and refinery projects.
Gaskets are packed individually in polybags with labels, then cartoned for export. Graphite-filled gaskets are protected from moisture; PTFE-filled units are stored flat. Shipping cartons are marked with product description, quantity, and lot number for warehouse traceability.
ASME Standard Data
Dimensions for spiral-wound gaskets used with ASME B16.5 flanges, transcribed from ASME B16.20-2023, Table SW-2.1-1: Dimensions for Spiral-Wound Gaskets Used With ASME B16.5 Flanges. NPS 1/2–24. The SI (mm) table is reproduced below; the companion U.S. Customary (in.) table has the same NPS range and column layout (see original standard). Gasket thickness (t) is not dimensioned in this table — see Figure SW-2.1-1; inner-ring thickness per GENERAL NOTE (a): 2.97 mm to 3.33 mm (0.117 in. to 0.131 in.).
1. Spiral-Wound Gasket Dimensions — Table SW-2.1-1 (SI, mm)
Source: ASME B16.20-2023, Table SW-2.1-1 (SI mm). Notes: (1) Gasket OD tolerance: NPS 1/2-8 ±0.8 mm (±0.03 in.); NPS 10-24 +1.5/-0.8 mm. (3) Gasket ID tolerance: NPS 1/2-8 ±0.4 mm; NPS 10-24 ±0.8 mm. (4) Centering-ring OD tolerance ±0.8 mm. (5) No Class 400 in NPS 1/2-3 1/2 (use Class 600); no Class 900 in NPS 1/2-2 1/2 (use Class 1500). (6) No flanges in NPS 3 1/2 and NPS 22 at Class 900/1500; no Class 2500 at NPS 3 1/2 or NPS 14 and larger. U.S. Customary (in.) companion table — same layout, see original standard (not duplicated here). “[Note (5)]” / “[Note (6)]” entries are transcribed verbatim from the standard and refer to notes (5) and (6) above.
Spiral-Wound Gasket Dimensions — ASME B16.20-2023
Spiral-Wound Gasket Dimensions — ASME B16.20-2023 Table SW-2.1-1
Dimensions for spiral-wound gaskets used with ASME B16.5 flanges, NPS 1/2–24, Class 150–2500. All values in millimeters (SI).
Notes — ASME B16.20-2023 Table SW-2.1-1
- Note (1): O.D. of gasket is common to the classes shown in the column heading.
- Note (2)/(3): I.D. of gasket by class; [Note (5)] in a cell means that size/class combination is not listed in the standard table (refer to the standard original).
- Note (5): Values not dimensioned in the extraction corpus for that class-size combination; preserved exactly from the ASME B16.20-2023 source.
- “—” = value not fully rendered in the PDF text-layer conversion; refer to the standard original.
- Data extracted and verified against the ASME B16.20-2023 source corpus; standard footnote numbering preserved as-is.
Spiral-Wound Gasket Dimensions — ASME B16.20-2023
Spiral-Wound Gasket Dimensions — ASME B16.20-2023 Table SW-2.1-1
Dimensions for spiral-wound gaskets used with ASME B16.5 flanges, NPS 1/2–24, Class 150–2500. All values in millimeters (SI).
Notes — ASME B16.20-2023 Table SW-2.1-1
- Note (1): O.D. of gasket is common to the classes shown in the column heading.
- Note (2)/(3): I.D. of gasket by class; [Note (5)] in a cell means that size/class combination is not listed in the standard table (refer to the standard original).
- Note (5): Values not dimensioned in the extraction corpus for that class-size combination; preserved exactly from the ASME B16.20-2023 source.
- “—” = value not fully rendered in the PDF text-layer conversion; refer to the standard original.
- Data extracted and verified against the ASME B16.20-2023 source corpus; standard footnote numbering preserved as-is.
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Frequently Asked Questions
All standard NPS sizes per ASME B16.20-2023, covering Class 150 through Class 2500. Custom dimensions available per drawing.
Yes — EN 10204 3.1 MTC with batch numbers, hardness reports for RTJ gaskets, and third-party inspection (BV / SGS) on request.
Yes, we manufacture non-standard sizes, special shapes, and non-standard materials per customer drawings within 15 days.