Selecting the right sealing material involves more than temperature ratings, chemical compatibility, and pressure requirements. Many industries also require materials and components to meet specific regulatory, safety, and performance standards.
Whether you are sourcing O-rings for a drinking water system, specifying gaskets for food processing equipment, or selecting materials for an electrical enclosure, understanding applicable standards can help reduce risk, improve compliance, and simplify supplier qualification.
The challenge is that standards such as NSF, ASTM, FDA, ISO, and UL are often referenced together, despite serving very different purposes.
This guide explains what each standard covers, when it applies, and how manufacturers use these standards when selecting sealing materials and components.
| Focus | Common Applications | |
|---|---|---|
| NSF 51 | Food equipment materials | Food processing and beverage manufacturing |
| NSF 61 | Drinking water system components | Water treatment and potable water systems |
| FDA | Food-contact materials | Food, beverage, and pharmaceutical equipment |
| ASTM | Material classification and testing | Engineering and material specification |
| ISO | Quality management systems | Supplier qualification and manufacturing |
| UL | Product safety and performance | Electrical and industrial equipment |
NSF 51 establishes requirements for materials used in food equipment and food-contact applications.
The standard helps ensure materials can safely be used in environments where direct or indirect food contact may occur.
Applications often include:
Seals, gaskets, and O-rings used in these environments frequently require materials that meet NSF 51 requirements.
NSF 61 applies specifically to drinking water system components.
The purpose of the standard is to evaluate whether materials may introduce contaminants into potable water systems.
Common applications include:
| NSF 51 | NSF 61 |
|---|---|
| Food-contact applications | Drinking water applications |
| Food processing systems | Potable water systems |
| Food safety focus | Water quality focus |
FDA compliance is another commonly referenced requirement in food, beverage, and pharmaceutical applications.
FDA regulations establish requirements for materials that may come into contact with food products.
For elastomers and sealing materials, compliance typically relates to the ingredients and composition of the material itself.
Common FDA-compliant sealing materials include:
FDA and NSF are often discussed together, but they are not interchangeable.
FDA regulations generally address material composition.
NSF standards focus on how materials and products perform within specific applications.
For example, a food-processing seal may require both FDA-compliant materials and NSF 51 certification depending on the application.
Engineers often use ASTM standards when evaluating:
ASTM standards help ensure manufacturers are comparing materials using consistent testing methods.
One of the most commonly referenced standards in the sealing industry is ASTM D2000.
ASTM D2000 classifies rubber materials based on performance characteristics such as:
The standard allows engineers to compare compounds using a common classification system rather than relying solely on trade names or proprietary material descriptions.
Companies pursuing certification must demonstrate consistent processes for:
Benefits often include:
UL (Underwriters Laboratories) standards are commonly referenced in electrical and industrial applications.
UL-recognized materials have been evaluated according to specific safety and performance requirements.
Depending on the application, evaluation may include:
UL standards are particularly important in:
Sealing materials used in electrical equipment often need to meet specific performance criteria related to fire safety and environmental exposure.
Using UL-recognized materials can simplify compliance and support equipment certification requirements.
The appropriate standard depends on where and how the seal will be used.
| Application | Common Standards |
|---|---|
| Food processing | NSF 51, FDA |
| Beverage production | NSF 51, FDA |
| Drinking water systems | NSF 61 |
| Water treatment equipment | NSF 61 |
| Electrical enclosures | UL |
| Control panels | UL |
| Industrial manufacturing | ASTM, ISO |
| OEM production environments | ASTM, ISO |
| Pharmaceutical equipment | FDA, ASTM |
In many cases, multiple standards apply simultaneously.
For example, a food processing application may require materials that satisfy both FDA requirements and NSF 51 standards.
To learn more about sealing materials and compliance requirements, explore:
Understanding standards is only one part of selecting the right sealing solution. Material compatibility, environmental conditions, regulatory requirements, and application performance all play important roles in long-term success.
North Coast Seal helps OEMs and manufacturers evaluate sealing materials for food processing, water treatment, electrical equipment, industrial manufacturing, and other demanding applications.
