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How NSF Certification Is Earned

ANSI Flange Pressure Ratings, nsf 61 372б what is nsf certification
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An NSF certification mark can look like just another stamp on a spec sheet, but in reality, a rigorous, multi-step process stands behind it. Achieving true NSF certification requires independent chemical testing, a full manufacturing facility audit, and mandatory ongoing checks over time (not a one-time review). Understanding this complete process is essential when specifying flanges for drinking water – and it is what separates a verified, listed product from a supplier’s self-declared compliance claim. In this guide, we cover what actually goes into NSF certification.

Key Elements of NSF Verification

Certification Element

What It Confirms

Full disclosure

Manufacturer submits material formulation, process, and intended use

Technical review

NSF reviews the formulation and parts list line by line

Laboratory testing

Samples tested under simulated drinking-water contact conditions

On-site facility audit

Auditors confirm production matches what was disclosed

Ongoing surveillance

Certification is maintained through continued audits, not a one-time approval

1. Complete Formulation & Material Disclosure

Certification to NSF/ANSI/CAN 60 and 61 begins with full transparency. The manufacturer must submit complete documentation covering exact material formulations, chemical components, manufacturing processes, and intended use. NSF safety evaluators analyze these disclosures to determine the specific testing parameters required for the product.

2. Line-by-Line Technical & Toxicological Review

The second stage is a comprehensive technical review. NSF evaluators review the formulation and parts list line by line. For a flange, this involves evaluating the base metal alloy, internal protective linings or coatings, and all wetted surfaces. The evaluation extends to secondary assembly components such as gaskets and seals. Evaluators review each material to assess its potential for chemical leaching and to calculate surface-area-to-volume exposure ratios under field operating conditions.

3. Laboratory Testing, Not a Paper Exercise

Following technical clearance, physical product samples are submitted to accredited NSF laboratories for extraction testing. This is where NSF 61 earns its reputation as a health-effects standard. Samples are exposed to conditions designed to simulate real drinking water contact and are measured against strict contaminant thresholds to ensure full health effects compliance – far beyond a simple “pass/fail” label.

4. On-Site Manufacturing Facility Audits

Physical testing alone does not grant certification – this step is what separates third-party certification by NSF from a self-declared compliance claim (a reality unknown to most buyers). NSF auditors inspect the physical facilities where flanges are forged, cast, or machined and confirm the raw materials, alloy batches, supplier sources, and quality assurance processes active on the shop floor match the exact specifications disclosed during the initial technical review.

5. Certification Isn't a One-Time Event

NSF certification is an active, ongoing status rather than a one-time accomplishment. Certified facilities are subject to annual ongoing surveillance and routine product re-testing to ensure ongoing compliance with the standard. If a manufacturer changes a material formulation, alters raw material suppliers, or allows its listing to lapse, the product loses certified status immediately – regardless of what is printed on the label.

What NSF Certification Means for Flange Buyers

Third-party certification provides verifiable proof of safety that self-declared ‘compliance’ statements cannot offer. When specifying drinking water piping components, a supplier’s NSF 61 certification claim is backed by rigorous, independent third-party verification. To ensure full system integrity, buyers should evaluate key verification factors:
  • Confirm which specific parts, sizes, alloys, and grades are covered by the certification.
  • Verify the certifying body and product listing directly rather than relying only on a spec sheet claim.
  • Keep the manufacturer’s Mill Test Reports on file alongside the certification. They provide different information, and both may be required.

Conclusion

The NSF mark represents a specific, repeatable process: full disclosure, technical review, laboratory testing, an on-site facility audit, and ongoing surveillance to keep the certification current. Every flange in API International’s CleanLine series follows each of those steps. Explore the comprehensive range of flanges in our online product catalog, or contact us for custom machining on nonstandard sizes and configurations. Get connected with a dedicated sales representative today, or call us at 503.692.3800.

Frequently Asked Questions

Does NSF test the finished flange or just the raw material?

Both. The technical review looks at material formulation and the parts list, and the laboratory testing evaluates how the finished product behaves under simulated drinking-water contact conditions.

How often does a certified facility get audited?

Certification includes ongoing surveillance rather than a single inspection. Certified facilities undergo continued audits to confirm they still match what was originally disclosed and tested.

Can a manufacturer change a flange's material and keep the same certification?

No. A material or formulation change requires re-disclosure and, typically, re-evaluation. Certification is tied to the specific product as reviewed and tested, not to the manufacturer generally.

Is an on-site audit required, or just recommended?

On-site audits are a required part of the certification process. NSF evaluates the physical manufacturing facility as a standard, mandatory requirement - never an optional add-on.