| Short answer: ISO/IEC 17025 is an accreditation of a calibration laboratory — not a certificate issued for an individual sensor. Rheonics ships every sensor with a calibration certificate and provides a fully documented NIST-traceable chain back to national standards. For most audit and regulatory needs, including FDA 21 CFR 820.72 and ISO 9001, this is exactly what is required. |
What products are involved?
SRV – Inline Viscosity Meter | SRD – Inline Density & Viscosity Meter | DVP | DVM
What is the purpose of this article?
To clarify what ISO/IEC 17025 accreditation actually is, explain what calibration certificates Rheonics provides, and show how NIST-traceable calibration satisfies FDA and ISO 9001 requirements in the vast majority of regulated applications.
TABLE OF CONTENTS
- The common point of confusion
- 1. What ships with every Rheonics sensor
- 2. The sensor-specific certificate — option CUS/VCAL2
- 3. How traceability is maintained
- 4. Does this meet FDA and ISO 9001 requirements?
- 5. When a customer genuinely needs an accredited ISO 17025 calibration
- 6. Summary
The common point of confusion
Customers often ask for "an ISO 17025 certificate." There is no such thing as an ISO 17025 certificate for a product. The three terms below are closely related but answer different questions:
| Term | What it means |
|---|---|
| ISO/IEC 17025 accreditation | A statement about a laboratory's competence, granted by an accreditation body. It is not issued for a product or instrument. |
| Calibration certificate | A document issued for a specific instrument, recording how it was calibrated, against what reference standard, and with what result. |
| NIST-traceable calibration | Certifies that the reference standards used are linked — through an unbroken chain of comparisons — back to national standards (NIST or equivalent national metrology institute). |
A calibration certificate can be NIST-traceable without being issued by an ISO 17025-accredited laboratory. Traceability answers what the calibration was referenced to; ISO 17025 accreditation answers the demonstrated competence of the lab that performed it.
1. What ships with every Rheonics sensor
Every Rheonics sensor is factory-calibrated and delivered with a standard Type-SR calibration certificate. This confirms the unit has been calibrated at the Rheonics facility before shipment.
2. The sensor-specific certificate — option CUS/VCAL2
If a more detailed, sensor-specific calibration certificate is required, order option CUS/VCAL2. This certificate documents:
- the NIST-traceable reference fluid used,
- the accuracy and precision achieved for that specific sensor serial number.
| ⚠ Important — order CUS/VCAL2 with the sensor: The calibration data is captured during the factory calibration process. If requested after the sensor has shipped, additional charges will apply because the sensor may need to be returned or recalibrated. Specify CUS/VCAL2 on your purchase order if your quality system or auditor requires per-sensor calibration data. |
3. How traceability is maintained
Rheonics performs factory calibration using NIST-traceable viscosity and density reference fluids supplied by Cannon Instrument Company. Cannon holds:
- ISO 17025 accreditation for calibration,
- ISO 17034 accreditation for reference material production.
Because the reference fluids carry these accreditations, the traceability chain from your sensor back to national standards is complete and documented. In addition, the Rheonics quality management system is ISO 9001 certified.
4. Does this meet FDA and ISO 9001 requirements?
For the great majority of regulated applications, yes. Both FDA equipment-calibration expectations (21 CFR 820.72) and ISO 9001 require that calibration standards be traceable to national or international standards and that calibration activities be documented. The NIST-traceable Rheonics certificate and the documented traceability chain through Cannon Instrument Company satisfy both requirements.
5. When a customer genuinely needs an accredited ISO 17025 calibration
A small number of regulated applications specify that the calibration itself must be performed by an ISO 17025-accredited laboratory. In that case, the sensor should be sent to a third-party ISO 17025-accredited calibration laboratory whose accreditation scope covers viscosity and density measurement. The Rheonics certificate and traceability documentation support that process — they do not replace an accredited calibration.
| If you have this requirement, contact Rheonics Support and we will advise on the appropriate path. |
6. Summary
| What you need | What Rheonics provides |
|---|---|
| Proof the sensor is factory-calibrated | Standard Type-SR calibration certificate — ships with every unit |
| Per-sensor calibration data with NIST-traceable fluid, accuracy and precision | Sensor-specific certificate, option CUS/VCAL2 — must be ordered with the sensor (post-shipment requests incur additional charges) |
| Documented traceability to national standards | NIST-traceable reference fluids from Cannon Instrument Company (ISO 17025 / ISO 17034 accredited) |
| Quality management assurance | Rheonics ISO 9001 certified |
| Calibration performed by an ISO 17025-accredited lab | Use a third-party accredited lab with viscosity/density scope — contact Rheonics Support for guidance |
| Not sure which option your application requires? Contact Rheonics Support and we will help you identify the right certificate for your quality system or regulatory requirement. |
Further information
Calibration
- Calibration of inline process viscometer SRV in field and factory — what calibration is, why it matters, and how Rheonics performs it.
- Calibration for Type-SR sensors in field, verification and re-calibration — step-by-step field calibration procedure using reference fluids.
- Doing an air check in Rheonics sensors — how to verify whether a sensor needs recalibration.
- Measurement device (sensor) repeatability and reproducibility — understanding accuracy, precision, and R&R for Rheonics sensors.
- The myth of accuracy for inline viscosity measurements — why accuracy has a specific and limited meaning for inline viscometers.
Certifications overview
- Rheonics certifications and compliance: overview — a single-page guide to all Rheonics certificates and approvals, including Ex, cULus, EHEDG, CE, and ISO 9001.
Downloads
- Rheonics Certificates page — download all compliance and approval certificates directly.
References
- [1] Cannon Instrument Company — cannoninstrument.com
- [2] FDA 21 CFR Part 820.72 — Inspection, measuring, and test equipment — ecfr.gov
- [3] ISO/IEC 17025:2017 — General requirements for the competence of testing and calibration laboratories — iso.org