NSF/ANSI 51: What Food Equipment Materials Certification Means for Sealants
A sealant going into a food plant, a commercial kitchen, or a walk-in cooler gets asked one question no residential caulk ever faces: can you document that this material belongs in a food area? NSF/ANSI 51 is the standard that answers it. Here is what the certification actually covers, how it differs from a "food grade" claim on a datasheet, and how to verify a listing before an auditor asks.
Last updated: August 14, 2026
The short version
- NSF/ANSI 51, Food Equipment Materials, certifies materials used to build and seal commercial food equipment and food areas. For a sealant, the cured material is what gets evaluated.
- Certification is third-party: formulation review, testing, facility audits, and a public listing. A "food grade" claim on a datasheet is usually self-declared.
- The standard is voluntary until a health inspector, buyer spec, plan review, or food safety audit references it. In food facilities, one of those almost always does.
- Listings state conditions of use, including a maximum use temperature. Match the listing to the zone and the duty, not just the brand name.
What NSF/ANSI 51 covers
NSF/ANSI 51 is the American National Standard for materials used in the construction of commercial food equipment: work surfaces, tanks, hoses, gaskets, coatings, plastics, and the sealants that join and seal all of it. It is a materials standard. It does not certify the design of a piece of equipment, and it does not certify a company. It certifies that a specific named material, in its end-use condition, is acceptable for a stated level of food contact.
For a sealant, the end-use condition is the cured bead, not the paste in the cartridge. Certification covers the formulation as reviewed, which is why a listing names an exact product rather than a product family, and why a manufacturer cannot substitute ingredients without going back through the process.
NSF certification carries three things a datasheet claim does not: testing of the material for its stated use, audits of the plant that makes it, and a public listing that anyone, including the inspector standing in your facility, can look up on the spot.
Food, splash, and nonfood zones
Food equipment standards divide surfaces by how likely food contact is. A food zone surface normally contacts food, or food may drain from it back into the product. A splash zone gets soiled by food in normal use but does not return food to the product. A nonfood zone is everything else.
A material is certified for a stated end use, and the zone is part of it. A listing that covers splash-zone use does not automatically cover food-zone use. When you check a listing, match it to where the sealant is actually going, and when in doubt specify to the stricter zone. The joints around a food plant most often land in splash and food zones: equipment perimeters, sink and counter joints, wall and panel seams in processing and storage rooms.
Practical rule: if a cleaning crew hoses it, wipes it, or food can touch it, treat the joint as needing a certified material. The cost difference against an uncertified sealant is small, and the documentation question disappears.
"Food grade" vs NSF-51 certified
Sealant marketing uses "food grade," "food safe," and "FDA compliant" almost interchangeably. Those phrases usually mean the ingredients conform to an FDA composition regulation for materials that may contact food. That conformity is real, but it is typically self-declared: the manufacturer states it, and nobody outside the company verifies it or audits the plant.
| Claim | Who verifies it | What you can show an auditor |
|---|---|---|
| "Food grade" / "FDA compliant" | The manufacturer, self-declared | A datasheet sentence |
| NSF-51 certified | NSF: testing, formulation review, plant audits | A public certification listing |
In a regulated food facility the difference is not academic. Inspections and audits run on documentation. A certification listing closes the question in thirty seconds. A marketing phrase invites a follow-up you may not be able to answer.
Where certification gets asked for
The standard itself is voluntary. What makes it binding in practice is being referenced, and in food environments it is referenced constantly:
- Health department plan reviews and inspections. Health codes require food-area surfaces to be smooth, durable, nonabsorbent, and easily cleanable. Certification is the accepted evidence that a sealed joint qualifies.
- Third-party food safety audits. Audit schemes used by food manufacturers and their customers ask for material documentation on food-area construction and repairs.
- Buyer and engineering specs. Equipment schedules and facility specs commonly call for NSF-listed materials in food and splash zones as a blanket requirement.
- Facility types: food and beverage processing plants, commercial kitchens, bottling and packaging lines, and cold storage, including walk-in coolers and freezers in food service.
What NSF-51 means when you are buying sealant
For sealant selection the certification interacts with three other requirements. First, chemistry: 100% silicone is the usual certified choice because it cures to a nonabsorbent, cleanable bead and tolerates wide temperature swings. Second, temperature: the listing states conditions of use, so check them against the duty, from freezer service to hot wash-down. Third, the joint itself still needs a sealant that performs mechanically, which is where ASTM C920 classifications come in. A food-area joint spec often reads as both: an ASTM C920 silicone that is also NSF-51 certified.
For cold storage specifically, our commercial freezer and walk-in cooler sealant guide covers where to seal, application temperature limits, and cure behavior in rooms that stay cold. For plant-wide zone requirements, the food processing sealants guide maps NSF requirements to each area of a facility.
NSF-51 Certified Sealants, Stocked by the Case
How to verify a listing
- Search the certified products database at nsf.org by manufacturer or product name.
- Match the exact product name on the cartridge to the listing. Certification attaches to a named product, not a brand or a product family.
- Read the conditions of use: the zone the listing covers and the maximum use temperature.
- Keep a copy of the listing with your facility documentation so it is on hand at inspection or audit time.
Watch for: datasheets that say "meets NSF requirements" or "NSF compliant" without a listing. If the product is not in the database, it is not certified, whatever the datasheet implies.
Frequently Asked Questions
What is NSF/ANSI 51 certification?
NSF/ANSI 51, Food Equipment Materials, is the American National Standard for materials used in the construction of commercial food equipment, including the sealants that join and seal it. Certification means NSF has reviewed the product formulation, tested the material for its stated end use, audits the manufacturing facility, and publishes the product in its certification listings. It is a third-party certification of the material itself, not a marketing description.
Is "food grade" the same as NSF-51 certified?
No. "Food grade" or "FDA compliant" on a datasheet usually refers to the ingredients conforming to an FDA composition regulation, and it is typically a self-declared claim by the manufacturer. NSF-51 certification is verified by a third party and backed by a public listing you can pull up during an inspection or audit. When a spec, auditor, or health inspector asks for documentation, a certification listing answers the question and a "food grade" claim does not.
Do walk-in cooler and freezer joints need NSF-51 sealant?
When the room stores or handles food in a regulated facility, the safe answer is yes. Health codes require food-area surfaces to be smooth, durable, nonabsorbent, and easily cleanable, and third-party food safety audits routinely ask for material documentation on anything sealing a food area. A certified silicone costs little more than an uncertified one, so specifying NSF-51 for cooler and freezer panel joints removes the question entirely.
Is NSF-51 required by law?
The standard itself is voluntary. It becomes binding when something references it: a health department plan review, a buyer or engineering spec, an equipment schedule, or a food safety audit scheme. In practice, food facilities treat certification as the default because it is the accepted evidence that a material is suitable for a food area, and arguing the point with an inspector costs more than the sealant.
What is the difference between NSF/ANSI 51 and NSF/ANSI 61?
NSF/ANSI 51 covers materials for commercial food equipment. NSF/ANSI 61 covers components in contact with drinking water, such as pipes, fittings, and plumbing sealants in potable water systems. A sealant certified to one is not certified to the other. Match the standard to the application: food equipment and food areas point to 51, potable water systems point to 61.
How do I verify a product is actually NSF-51 certified?
Search the certified products database on nsf.org by manufacturer or product name. The listing states the exact product name, the standard, and the conditions of the certification. Match the product name on the cartridge to the listing exactly, and keep a copy of the listing with your facility documentation so it is on hand at audit time.
Does an NSF-51 listing cover temperature?
Listings state conditions of use, including a maximum use temperature. Check that the listed conditions cover your service range. Cold rooms are rarely the limiting case, since freezer service temperatures are well within what a cured silicone tolerates, but hot equipment, wash-down, and cook areas can be, so verify the listed temperature against the actual duty.
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