PTFE Gasket
Product Description
Virgin PTFE flat gasket with outstanding chemical resistance across virtually the entire pH range. Ideal for aggressive media in chemical, pharmaceutical, and food processing industries.
Available in all standard sizes and pressure classes, with custom dimensions per drawing. Each gasket is marked per standard requirements for full traceability.
Applications
Virgin PTFE gaskets provide unmatched chemical inertness across nearly the entire pH range, making them the sealing choice for corrosive acid and alkali piping in chemical processing plants, pharmaceutical manufacturing, and semiconductor wafer fabrication. They seal flange joints handling hydrochloric acid, sulfuric acid, caustic soda, and organic solvents at temperatures from -200°C to 260°C and pressures up to 40 bar depending on size and class.
Typical applications include acid transfer lines in pickling operations, bleach and chemical dosing skids, food and dairy processing CIP systems (FDA-compliant grades available), and ultra-pure water distribution in semiconductor fabs. PTFE’s non-stick surface prevents product buildup and simplifies cleaning in sanitary service.
They are also used in chlorine gas handling, photographic processing chemistry lines, and electroplating tank piping. The flat gasket conforms to ASME B16.21 dimensions for RF and FF flange faces in Class 150 through Class 900 ratings. Custom shapes, punchings, and envelope gaskets are available per drawing.
Quality Assurance & Certification
PTFE gaskets are die-cut from virgin PTFE sheet material sourced from certified manufacturers, with batch numbers linking each lot to raw material certificates. We supply EN 10204 3.1 documentation for the PTFE raw material, including density, tensile strength, and chemical resistance data. FDA-compliant grades are available for food and pharmaceutical service.
Each gasket lot undergoes dimensional inspection to confirm inner diameter, outer diameter, and thickness per ASME B16.21 tolerance tables. Visual inspection checks for cuts, bubbles, or delamination. Third-party material verification by SGS or BV can be arranged for regulated industry orders.
Gaskets are sealed in polybag packs with product labels identifying size, class, material grade, and lot number. They are packed in sturdy cartons for export shipping. PTFE is dimensionally stable and requires no special storage conditions beyond protection from sharp objects and direct sunlight.
ASME Standard Data
Dimensional data for non-metallic flat gaskets (PTFE gaskets included) transcribed from ASME B16.21-2021, Nonmetallic Flat Gaskets for Pipe Flanges. NPS 1/2–24, Class 150 and Classes 300/400/600/900. The 2021 edition merges SI (mm) and U.S. Customary (in.) into a single table; values are shown as mm (inches). Gasket thickness is selected by the user (the standard states ‘selection of gasket thickness is the responsibility of the user’) and is not tabulated below. Non-metallic flat gaskets are not used at Class 1500 / Class 2500.
1. Gasket Dimensions for ASME B16.5 Class 150 Flanges — Table 4.1-4 (mm / in.)
Source: ASME B16.21-2021, Table 4.1-4 — Gasket Dimensions for ASME B16.5 Class 150, Pipe Flanges and Flanged Fittings. GENERAL NOTE: Dimensions are in millimeters (inches), except hole diameter dimensions, which are in fractional inches (decimal inches). Values transcribed verbatim; no conversion applied. Gasket thickness: 待补 (selected by user, not given in the standard).
2. Flat Ring Gasket Dimensions for Classes 300/400/600/900 — Table 4.1-5 (mm / in.)
Source: ASME B16.21-2021, Table 4.1-5 — Flat Ring Gasket Dimensions for ASME B16.5, Pipe Flanges and Flanged Fittings, Classes 300, 400, 600, and 900. GENERAL NOTE: Dimensions are in millimeters (inches). ‘…’ = no listed size (e.g. Class 900 at NPS 3 1/2 and NPS 22). “…” denotes no listed size per the standard. PTFE is one of the non-metallic materials covered by B16.21; dimensions are common to all non-metallic flat gaskets (not per-material).
Nonmetallic Flat Gasket Dimensions — ASME B16.21-2021
Gasket Dimensions for ASME B16.5 Class 150 — ASME B16.21-2021 Table 4.1-4
Nonmetallic flat gasket dimensions for B16.5 Class 150 flanges, NPS 1/2–24. Values in mm (in.).
Flat Ring Gasket Dimensions, Classes 300–900 — ASME B16.21-2021 Table 4.1-5
Flat ring gasket dimensions for ASME B16.5 flanges, Classes 300, 400, 600 and 900, NPS 1/2–24. Values in mm (in.).
Notes — ASME B16.21-2021 Tables 4.1-4 / 4.1-5
- Gasket I.D. is common across all classes; O.D. varies by pressure class and flange facing (full face vs raised face).
- ASME B16.21-2021 covers nonmetallic gaskets through Class 900; Classes 1500/2500 are not included in this standard (see the standard’s foreword).
- “—” = value not fully rendered in the extraction corpus; refer to the standard original.
- Data extracted and verified against the ASME B16.21-2021 source corpus; footnote numbering preserved as-is.
Nonmetallic Flat Gasket Dimensions — ASME B16.21-2021
Gasket Dimensions for ASME B16.5 Class 150 — ASME B16.21-2021 Table 4.1-4
Nonmetallic flat gasket dimensions for B16.5 Class 150 flanges, NPS 1/2–24. Values in mm (in.).
Flat Ring Gasket Dimensions, Classes 300–900 — ASME B16.21-2021 Table 4.1-5
Flat ring gasket dimensions for ASME B16.5 flanges, Classes 300, 400, 600 and 900, NPS 1/2–24. Values in mm (in.).
Notes — ASME B16.21-2021 Tables 4.1-4 / 4.1-5
- Gasket I.D. is common across all classes; O.D. varies by pressure class and flange facing (full face vs raised face).
- ASME B16.21-2021 covers nonmetallic gaskets through Class 900; Classes 1500/2500 are not included in this standard (see the standard’s foreword).
- “—” = value not fully rendered in the extraction corpus; refer to the standard original.
- Data extracted and verified against the ASME B16.21-2021 source corpus; footnote numbering preserved as-is.
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Frequently Asked Questions
All standard NPS sizes per ASME B16.21-2021, covering Class 150 through Class 900. 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.