Polysulfone FDA & Food-Grade Compliance
Polysulfone (PSU) and polyphenylsulfone (PPSU) carry the regulatory credentials required for food contact, medical device, and potable water applications. Both grades comply with FDA 21 CFR 177.1655 for repeated-use food-contact articles, USP Class VI biocompatibility protocols for medical devices, and NSF 51 for food equipment materials. This page explains each certification, what it covers, how to verify compliance for a specific lot of material, and which grade applies to which regulated end-use.
At a glance:
- FDA 21 CFR 177.1655: polysulfone for food contact — both PSU and PPSU
- USP Class VI: biocompatibility testing passed — both Udel and Radel grades
- NSF 51: food equipment materials certification for food-zone contact
- NSF 61: drinking water system components (Udel PSU specific)
- Steam autoclave compatible — 250–270°F (121–132°C) per standard hospital cycles
- Certificates of conformance and FDA compliance letters available per lot
FDA 21 CFR 177.1655 — Polysulfone for Food Contact
What the Regulation Covers
Title 21 of the Code of Federal Regulations, Part 177, Section 177.1655 specifically addresses polysulfone resins for use in articles that contact food. The regulation establishes:
- Composition requirements for the base polysulfone polymer
- Permitted adjuvants (stabilizers, processing aids) within defined concentration limits
- Conditions of use: repeated-use articles in contact with food under various temperature conditions
Both Solvay Udel PSU and Radel PPSU meet the compositional requirements of 21 CFR 177.1655 for the natural (uncompounded) grades stocked in sheet and rod form.
Conditions of Use
FDA food-contact regulations define conditions of use by temperature and food type. Polysulfone's approval under 177.1655 covers repeated-use contact including hot-fill conditions up to the material's rated service temperature. The continuous-use temperature of 300°F (PSU) or 350°F (PPSU) exceeds the thermal conditions of typical food-processing and food-service steam cleaning, steam-table holding, and CIP sanitation.
FDA 21 CFR 177.1655 compliance applies to the base resin. If a polysulfone part is fabricated using adhesives, coatings, pigments, or other secondary materials, those materials must also comply with applicable FDA food-contact regulations. Natural amber stock shapes without secondary processing are covered by 177.1655 as supplied.
USP Class VI Biocompatibility
What USP Class VI Means
United States Pharmacopeia (USP) Class VI is a biocompatibility testing protocol widely used in medical device qualification. It consists of three in vivo tests:
- Systemic injection test — acute systemic toxicity from intravenous injection of extraction solution
- Intracutaneous test — local tissue reaction from injection of extraction solution
- Implantation test — reaction to subcutaneous implantation of material samples
Passing all three tests establishes that extractables from the material under specified extraction conditions (physiological saline, cottonseed oil, alcohol, polyethylene glycol at defined temperatures and durations) do not produce acute toxic or inflammatory responses.
Both Solvay Udel PSU and Radel PPSU grades in their standard natural formulations have passed USP Class VI protocols. This biocompatibility classification is a standard requirement for materials used in reusable medical devices, surgical instruments, and fluid-contact medical equipment.
NSF 51 — Food Equipment Materials
NSF International Standard 51 covers materials that contact food in commercial food processing and food-service equipment. Certification under NSF 51 requires:
- Material composition compliance with FDA food-contact regulations
- Performance testing appropriate to the intended use
- Third-party listing and periodic facility audits
Solvay's Udel PSU and Radel PPSU grades in standard unfilled form carry NSF 51 listing, qualifying them for food-zone components in commercial equipment. This certification is commonly required for dairy processing equipment, commercial cooking equipment, and food-service machinery.
Applications utilizing NSF 51-certified polysulfone:
- Dairy processing fittings and sight glasses
- Steam-cleanable food-service equipment components
- Food-contact structural components in processing lines
- Commercial beverage dispensing equipment parts
NSF 61 — Drinking Water System Components
PSU for Potable Water
NSF/ANSI Standard 61 covers materials and components that contact drinking water. Udel PSU has been evaluated and listed under NSF 61 for potable water contact, supporting its use in:
- Hot water plumbing valves and fittings
- Water treatment equipment
- Municipal and commercial water distribution system components
NSF 61 is particularly important for applications where polysulfone contacts chloraminated municipal water supplies. Unlike polycarbonate, which can stress-crack from chloramine exposure, PSU maintains its integrity in these conditions.
NSF 61 listing is grade-specific and manufacturer-specific. When specifying polysulfone for drinking water contact, confirm the specific Solvay Udel grade being supplied carries active NSF 61 listing. PPSU's NSF 61 status should be verified at the time of material procurement — PSU is the more commonly certified grade for this application.
Autoclave Compatibility and Sterility Claims
Steam Sterilization Conditions
Polysulfone stock shapes are compatible with standard steam sterilization conditions used in healthcare:
| Sterilization Cycle | Temperature | Pressure | Compatibility |
|---|---|---|---|
| Gravity cycle | 250°F / 121°C | 15 psi | PSU and PPSU — both compatible |
| Prevacuum cycle | 270°F / 132°C | 27 psi | PSU — moderate cycles; PPSU — 1,000+ cycles |
| Flash / IUSS | 270°F / 132°C | 27 psi | PPSU preferred for repeated use |
| Class B dental | 273°F / 134°C | 29 psi | PPSU required |
Steam sterilization creates sterile surfaces — it does not affect the base material's FDA or USP compliance status. A polysulfone tray that complies with 21 CFR 177.1655 as a food-contact article before autoclaving continues to comply after sterilization cycles, provided the material is not degraded.
ETO and VHP Sterilization
Both PSU and PPSU are compatible with ethylene oxide (ETO) sterilization at room temperature. Hydrogen peroxide vapor (VHP) sterilization is also compatible with polysulfone and leaves no toxic residue on surfaces.
Obtaining Compliance Documentation
When polysulfone is used in a regulated product, procurement documentation should include:
- Certificate of conformance (C of C) — confirming the lot meets ASTM D6098 (PSU) or D6107 (PPSU)
- FDA compliance letter — from Solvay confirming 21 CFR 177.1655 compliance for the specific resin grade
- USP Class VI test report — third-party biocompatibility test report for the grade
- NSF listing verification — current listing from NSF International's online database (listings can expire)
Summary Compliance Matrix
Request FDA-compliant polysulfone with lot documentation
Request a Quote →More related guides
Cross-cluster suggestions to help shoppers and engineers explore adjacent topics:
Applications
Industries
Compare to other materials
Frequently asked questions — Polysulfone FAQ