FDA-compliant O-rings: materials and approval
FDA-compliant O-rings are mandatory in the food, beverage and pharmaceutical industries. We explain what FDA compliance means, what FDA 21 CFR 177.2600 regulates, how it differs from USP Class VI and 3-A, and which NH O-RING materials are FDA-compliant.
- FDA-compliant means that the material meets the FDA requirements for food contact. What is approved is the formulation, not the individual O-ring.
- The central regulation is FDA 21 CFR 177.2600, a list of the approved elastomer constituents with extraction limits for aqueous and oily media.
- FDA, USP Class VI, 3-A and EC 1935/2004 test different things and complement one another depending on the industry and process.
- FDA-compliant at NH O-RING are FKM 75 FDA, the FFKM compounds NH4700, NH7700 and NH5750, FEP-FKM, FEP-silicone and PTFE60.
- ECOLAST NH4700 has the broadest certification: FDA, USP Class VI and 3-A, suitable for demanding pharmaceutical and food applications.
What does FDA compliance mean for O-rings?
The Food and Drug Administration (FDA) is the US authority responsible for the supervision and regulation of food, medicines, medical devices, tobacco products and cosmetics in the United States. Its task is to protect public health. It ensures that products are safe, effective and correctly labelled, for domestic as well as imported goods.
When people speak of an FDA-compliant O-ring, this does not refer to an approval of the individual sealing ring as a product. What is meant is that the material used consists of constituents that are listed as safe in the relevant FDA regulations for food contact. The O-ring itself does not undergo any official approval procedure. The decisive factor is the formulation of the elastomer or plastic.
For sealing technology this comes down to one clear question: is the material suitable for contact with food, beverages, drinking water or pharmaceutical media? This is precisely what the relevant section of the FDA regulations governs, which we look at below.
FDA 21 CFR 177.2600: the rule for rubber in food contact
The governing provisions are set out in the Code of Federal Regulations (CFR), Title 21. For elastomers and rubber that come into contact with food, regulation FDA 21 CFR 177.2600 is central. It is found in Title 21, Chapter 1, Subchapter B, Part 177, Subpart C.
At its core, this provision is a list of the approved base elastomers and vulcanization materials that may be used in rubber production and are regarded as safe. It also contains requirements for extraction tests, which determine how many constituents a material releases on contact with aqueous and oily media.
For the compatibility of rubber with food, the FDA distinguishes two categories:
| Food class | Description | Examples |
|---|---|---|
| Class I | Food with a fat and oil content. Materials that pass here are also suitable for Class II. | Edible oils, butter, milk and dairy products, cooking oils |
| Class II | Aqueous media without edible oils or dairy products. | Water, non-alcoholic beverages, alcoholic beverages, aqueous solutions |
Materials that meet these requirements are used in seals, conveyor belts, guards and similar components in food processing. Typical environments are dairies, breweries, beverage filling, commercial kitchens, pharmaceutical operations and the cosmetics industry.
Distinction: USP Class VI, 3-A and EC 1935/2004
FDA compliance is not the only requirement in hygienically sensitive industries. Depending on the application, further standards come into play, each of which serves a different purpose. These standards do not replace one another but complement each other.
For a pure food application, FDA compliance is often sufficient, supplemented in Europe by EC 1935/2004. For pharmaceutical processes, USP Class VI is also customary, and in dairy processing the 3-A standard. Which combination you need depends on your industry and your process.
Which NH O-RING materials are FDA-compliant?
At NH O-RING we offer FDA-compliant compounds in several material families. These cover requirements ranging from simple food contact through to pharmaceutical processes. The following overview shows our FDA-compliant materials with their operating temperatures and additional approvals.
| Material | Family | Operating temperature | Approval | Hardness |
|---|---|---|---|---|
| FKM 75 FDA | FKM | −25/+200 °C | FDA | 75 ±5 Shore A |
| ECOLAST NH4700 | FFKM | −20/+270 °C | FDA, USP Class VI, 3-A | 70 ±5 Shore A |
| ECOLAST NH7700 | FFKM | −20/+270 °C | FDA, USP Class VI | 70 ±5 Shore A |
| ECOLAST NH5750 | FFKM | −25/+270 °C | FDA | 75 ±5 Shore A |
| FEP-FKM | FEP-encapsulated | −25/+205 °C | FDA | 90 ±5 Shore A |
| FEP-silicone | FEP-encapsulated | −60/+205 °C | FDA | 90 ±5 Shore A |
| PTFE60 | PTFE | −250/+250 °C | FDA | 60 ±5 Shore D |
Within the FFKM family, ECOLAST NH4700 is the most broadly certified compound: alongside FDA compliance it also holds USP Class VI and the 3-A standard, making it suitable for particularly demanding applications in pharmaceuticals and food processing. NH7700 adds FDA and USP Class VI, and NH5750 covers FDA compliance.
In the FKM family, FKM 75 FDA provides a proven and economical solution for food contact. For particularly broad chemical resistance or high temperatures, the FFKM materials are recommended.
For the FEP-encapsulated O-rings, both FEP-FKM and FEP-silicone are FDA-compliant. The FEP jacket offers almost universal media resistance, while the core provides the restoring force. PTFE60 as a solid material is also FDA-compliant and, at −250/+250 °C, covers an exceptionally wide temperature range.
How to choose the right FDA-compliant O-ring
Selecting an FDA-compliant O-ring follows the same basic rules as any material choice, supplemented by the question of the required evidence. Three points are decisive here.
Medium and chemical resistance. Which substances contact the O-ring in operation? For aggressive media, frequent cleaning cycles with harsh cleaning agents (CIP and SIP) or solvents, FFKM is the most robust choice. For many aqueous and fatty foods, FKM 75 FDA is sufficient.
Temperature. The operating temperature narrows down the materials. FKM 75 FDA covers −25/+200 °C, the FFKM compounds reach up to +270 °C, and PTFE60 covers the widest range at −250/+250 °C. FEP-silicone, at −60 °C, is suitable for particularly low temperatures.
Required evidence. Clarify early on whether, in addition to FDA compliance, further standards such as USP Class VI or 3-A are required. This determines whether a standard FDA material is sufficient or whether a more broadly certified compound such as NH4700 is needed.
Which material suits your specific medium can be narrowed down with our resistance table. If in doubt, we will review your operating conditions and recommend the suitable material together with the necessary certificates.
Frequently asked questions
What does FDA-compliant mean for an O-ring?
Which regulation governs FDA-compliant elastomers?
Which NH O-RING materials are FDA-compliant?
How do FDA, USP Class VI and 3-A differ?
Do I also need conformity to EC 1935/2004 in Europe?
Which FDA-compliant material is suitable for high temperatures?
Do I receive an FDA certificate with the O-rings?
