Extensive Requirements Needed for Use
Food grade o-rings are designed to be used in specific applications or with precise purposes. However, these seals come in many available material choices to give you the ability to match your application with the appropriate solutions.
To earn ‘food grade’ status, an o-ring (or another seal) must meet standards for quality and cleanliness, and do so while still maintaining characteristics needed by food manufacturers to perform in hostile environments. In food processing, factors such as high temperatures, steam, and chemical contaminants are common.
The Food and Drug Administration (FDA) has approved several materials for use in sealing products designed for food, medical, and pharmaceutical production. These materials have been determined to meet the safety conditions set forth by the organization, while also complying with the needs dictated by the application (chemical and temperature resistance, etc.).
Seals in the food processing sector are required to be both safe and resilient, even in dynamic applications. Food grade o-rings also need specific properties to be effective, given the nature of the industry in which they operate. Some of these other properties include:
- Resistant to bacterial build-up
- Operate in a wide range of temperatures
To ensure sealing materials meet all of these requirements, there are a number of standards to meet from government and public organizations tasked with making sure any elements in food processing, water, and bio or pharmaceutical industries won’t harm consumers.
Requirements of Food Grade O-Rings
Let’s examine the compliance measures used to judge or indicate which o-ring and sealing materials are suitable and approved for use in applications that have human-centric endpoints.
FDA Compliant per CFR 21.177.2600
The FDA is the U.S. government agency responsible for food safety and ensuring human pharmaceuticals, biological products, and medical devices are safe and effective (among other duties). Through its Code of Federal Regulations, the FDA manages a list of materials and chemicals that are approved for contact with foods.
FDA CFR 21.177.2600 describes the regulations for ‘Rubber articles intended for repeated use.’ In short, a material must be on this list to be used in products intended for repeated use in all stages of food manufacturing, preparation, and transportation.
Furthermore, the statute goes on to specify limits on extractible products if the FDA rubber seal is to be used in contact with aqueous or fatty foods. The regulation specifies extraction test limits in water and n-hexane. It should be noted that while a component may be made from an FDA rubber material that is suitable for food contact; this does not mean that the part is technically suitable for its intended application.
USP Class VI Compliant
This is a set of biocompatibility testing requirements established by the U.S. Pharmacopeia (USP), a non-profit organization whose standards also inform decision making conducted by the FDA. By ensuring that material is non-toxic, and won’t result in rejection by the body, biocompatibility testing ensures that a rubber is safe for use with living tissue. This standard is vital for materials like medical silicone, which is used in stents and catheters.
3A Dairy Compliance
In order to get a 3A certificate, an organization must prove to an independent assessor that their product is on the FDA list of approved substances, and that their facilities, procurements, and procedures all meet established standards. Compliance is measured through both procedure and traceability. There are several 3A compliance measures; in this case, it means the material is approved for use in the dairy industry.
NSF 61, KTW, WRAS Compliant
The National Sanitation Foundation (NSF) develops the standards for testing and measures the amount of lead and other heavy metals, and organic materials that are released into the water supply when the product is used. NSF-61 is a standard addressing material certification related to the sanitary and potable water industry, including joints, seals, and custom molded parts. KTW (Germany) and WRAS (United Kingdom) represent other standards developed in Europe.
FDA Compliant Food Grade O-Ring Materials
While there are many standards to meet and many attributes required from materials used in seals in this space, there remain many options to consider in this realm. Let’s look at the materials that are commonly used for food grade o-rings, and some specific formulation examples for each.
One of the more popular food grade o-ring materials, silicone is highly stable and can operate in a wide range of temperatures. It is an excellent material choice when avoiding cross-contamination is a priority.
Marco Rubber formulation: S1146 — USP Class VI compliant, this material is suited for static, bio-related applications. Manufactured and packaged in a ‘clean room’ environment.
Nitrile Rubber (Buna-N)
Known for excellent impact resistance and the ability to remain flexible through temperature cycles, this material displays remarkable durability even after repeated cycles. It’s a common choice for food and medical processing.
Marco Rubber formulation: B1105 — This FDA compliant material provides strong general purpose usage due to tear and abrasion resistance, and basic resistance to common lubricants.
Ethylene propylene diene monomer is perhaps the most widely-used food-grade material and is able to withstand a wide array of temperatures and provides resistance against phosphate esters and lipids.
Marco Rubber formulation: E1097 — EPDM’s wide range of temperature resistance is augmented in this particular formulation, which is FDA compliant, and has NSF 61 and 3A Dairy compliance.
FKMs don’t absorb water and bring excellent high-temperature resistance to the table as well. When you have applications using steam or hot liquids are present, this material is a strong choice.
Marco Rubber formulation: V1118 — This FKM from Viton® is both FDA and Class VI compliant, and has excellent resistance to mineral oil, greases, and many organic solvents and chemicals.
FFKM is regarded as the best performing material available for sealing solutions, particularly in demanding environments, and has the best temperature resistance and chemical resistance available.
Marco Rubber formulation: Z1318 — This Markez® formulation is a top-of-the-line material designed for high-temperature and chemically abrasive medical and food applications. It is FDA and Class VI compliant and can be manufactured and packaged in cleanroom conditions.
Find Your Food Grade O-Ring with Marco Rubber
Marco Rubber & Plastics produces FDA-grade o-rings, gaskets, rubber seals, and custom-designed components from the full range of compliant materials.
With access to more than one billion sealing solutions throughout our expansive production network, we offer a comprehensive line of food grade o-rings and other sealing solutions. However, the ultimate performance of a seal will depend on how well it matches the application itself. It’s important to discuss all aspects of your application with an application engineer to find and consider all the right potential solutions. With more than 14,000 repeat customers worldwide, Marco Rubber has proven it can be counted on to find the ideal match between application and sealing solution.