Food grade is a term you will come across often at Qseals. It means that materials may come into contact with food, beverages and pharmaceutical products without affecting their quality or safety. Do you work in the pharmaceutical industry, biotechnology or medical technology? Then, alongside the FDA and EC 1935/2004, you will often meet a third requirement: USP Class VI. On this page you can read what USP Class VI is and what to look out for when choosing your mechanical seal.
What is USP Class VI?
The United States Pharmacopeia (USP) is an independent, non-profit American organisation that sets standards for the quality and safety of medicines, dietary supplements and ingredients. These standards are published in the USP-NF (United States Pharmacopeia – National Formulary), a reference work that the FDA also uses. Chapter <88> of the USP describes the Biological Reactivity Tests, In Vivo: tests that determine whether plastics and elastomers are biocompatible, in other words whether they cause no harmful reaction in living tissue.
Based on these tests, materials are divided into six classes, from Class I up to and including Class VI. Class VI is the strictest class. A material only receives this classification once it passes three tests:
- Systemic injection test: extracts of the material are injected to check for toxic effects throughout the body;
- Intracutaneous test: extracts are injected under the skin to assess local irritation;
- Implantation test: the material itself is implanted to assess the tissue reaction.
Different extraction media are used for the extracts, such as a saline solution, an alcohol-saline solution, polyethylene glycol and vegetable oil. This tests how the material behaves with a wide range of media.
Why is USP Class VI important for mechanical seals?
In the pharmaceutical and biotech industries, seals in pumps, mixers, agitators and bioreactors come into direct contact with the product. An O-ring or other plastic component that releases substances can make an entire production batch unusable. That is why many manufacturers and end customers require the secondary seals in a mechanical seal to be USP Class VI certified. Both the manufacturer and the patient want to be sure that the end product is safe.
Please note: USP Class VI applies to plastics and elastomers. For the seal faces and metal parts of a seal, you look at the requirements of the FDA and EC 1935/2004. These requirements are often combined: an O-ring that is both FDA compliant and USP Class VI certified can be used in the food industry as well as the pharmaceutical industry.
USP Class VI materials at Qseals
At Qseals we supply the plastic and elastomer parts of a mechanical seal in a USP Class VI version, so you can match the complete seal to your medium and your process.
Elastomers and O-rings
PTFE and FEP-encapsulated O-rings
State in your enquiry that you need a USP Class VI version. We will then make sure the right materials are used in your seal.
Food grade mechanical seals from Qseals
Looking for food grade mechanical seals? Take a look at our extensive range. Qseals has a very diverse range and a suitable solution for almost every application, from component seals and cartridge seals to compressor seals. Need something specific? In our factory in Wezep we make custom seals and parts, using the materials that suit your process and regulations. Our experienced technical specialists are happy to help you choose the right material.
Want to know which version suits your application? Contact us or request a quote directly.
