PTFE is chemically inert and non-shedding, so it is the usual choice for liners, gaskets, seals and tubing in clean service. Approval depends on resin, additives, process and documentation.
Approvals commonly asked for
| Area | Typical reference |
|---|---|
| Food contact (US) | FDA 21 CFR 177.1550 for perfluorocarbon resins |
| Food contact (EU) | Regulation (EC) No 1935/2004 and Regulation (EU) No 10/2011 where applicable |
| Pharmaceutical | USP Class VI and USP <87>/<88> biological tests |
| Medical | ISO 10993 series |
| Drinking water | National approvals such as NSF/ANSI 61 or WRAS (check which apply) |
| Hygienic equipment | EHEDG and 3-A guidance for design |
Approvals attach to a specific grade and processor, not to a polymer name. Ask for the declaration of conformity and the test report that covers your exact grade.
Grade guidance
- Virgin or modified PTFE only, no regrind, no pigments unless approved.
- Filled grades are usually not approved for food, with exceptions such as certain mineral-filled or carbon-filled grades declared compliant for specific temperatures.
- Semiconductor and ultra-pure chemicals use PFA and high-purity modified PTFE with low metal extractables. Machining and cleaning must keep ionic contamination down.
Keeping it clean
- Dedicated tools and clean benches. No cross-contact with bronze-filled or lubricated work.
- Cutting fluids that are food-safe or none at all.
- Final cleaning, drying and double-bag packaging.
- Lot traceability on the finished part.
- Cleanroom packing for semiconductor use.
Hygiene pitfalls
- Crevices and sharp grooves trap product. Design for cleaning (CIP/SIP).
- Dark fillers hide contamination.
- Gaskets that creep can form gaps where bacteria collect.
- Static charge may attract dust. Use grades with the right conductivity if explosion risk exists.
Documentation to keep
Declaration of conformity, material certificate, migration test results, lot record, cleaning record. Auditors in food and pharma check the trail.
About this article. It is original writing prepared from public sources, standards and general industry practice. It is not a copy of any book or standard and it is not engineering advice. Confirm values against the current edition of the standard and test in your own application. Only analyse material you own or are entitled to analyse.
