What a verification fluid is, how it differs from a calibration fluid and a process-control standard, and where it fits in an ISO 11171:2022-compliant QC chain.
A verification fluid is a NIST-traceable reference material used to confirm that an optical particle counter’s existing calibration is still valid. It answers a specific question on a specific cadence: do I need to re-calibrate? The instrument was sized-calibrated some months ago against the primary standard; the verification fluid checks that the calibration is still holding before the lab commits to a measurement campaign.
It is the lightest-touch reference material in the lab’s QC chain. A full sizing calibration (against the CINSTAN Calibration Kit) is an annual or semi-annual event — substantial procedure, takes several hours. A process-control standard runs interleaved through every batch — substantial volume of usage. A verification fluid is run once at the start of a campaign — quick check, definite answer, no re-calibration required if it passes.
Three distinct reference materials, three distinct jobs.
| Calibration Fluid CINSTAN-CFK |
Verification Fluid CINSTAN-VF |
Process Control Standard CINSTAN-PCS |
|
|---|---|---|---|
| Question it answers | What are my channel-table values? | Is my calibration still valid? | Is my instrument in statistical control today? |
| Typical cadence | Annual | Start of each measurement campaign / after system change | Every production batch (start + end) |
| Time to run | Several hours (full sizing calibration) | One shot — minutes | One sample, runs in line with normal batch |
| Volume used per cycle | One full kit per annual calibration | One bottle per verification event | Several bottles per year, depending on PCS frequency |
| NIST traceability | Traceable to SRM 2806d | Traceable to SRM 2806d | Traceable to SRM 2806d |
| What you do if it fails | (Calibration is the corrective action) | Re-calibrate against CINSTAN-CFK | Lock the instrument, investigate cause, re-calibrate if needed |
All three are part of an ISO/IEC 17025-compliant QC chain. Accredited labs typically use all three together: annual calibration sets the channel table, periodic verification confirms the calibration is still valid between annual events, and per-batch process-control standards catch day-to-day drift. The three roles are complementary, not interchangeable.
ISO 11171:2022 does not prescribe a fixed verification interval — that’s a lab-specific decision driven by sample volume, accreditation requirements, and the lab’s observed PCS-trending pattern. Typical industrial practice falls into one of these patterns:
The verification result is binary in operational terms: either the measured counts agree with the certified counts (within the configured tolerance) and the instrument continues in service unchanged, or they do not agree and the lab triggers a full re-calibration before resuming production.
CINRG’s verification fluid product is CS-CINSTAN-VF. Key facts:
CS-CINSTAN-VF is available through the CINRG online shop or via the CINRG contact form for volume orders, international shipping, or first-time buyers requiring documentation in advance.
A verification fluid is a NIST-traceable reference material used to confirm that an optical particle counter’s existing calibration is still valid — typically as a one-shot check at the start of a measurement campaign. It is distinct from a calibration fluid (used to set the instrument’s channel table during annual sizing-calibration) and from a process-control standard (run repeatedly during production batches to confirm statistical control). Verification answers "is the calibration still good?" on a defined schedule.
Three distinct roles. Calibration fluid: used once a year to set the instrument’s channel table (CINSTAN-CFK). Verification fluid: used periodically — typically at the start of a measurement campaign or after a system change — to confirm the calibration is still valid (CINSTAN-VF). Process-control standard: used repeatedly during production batches, trended against upper/lower control limits, to confirm day-to-day instrument performance (CINSTAN-PCS). All three are traceable to the same NIST SRM 2806d primary.
Typical industrial practice: run a verification fluid at the start of any extended measurement campaign, after any system change (sensor cleaning, software update, hardware service), as part of monthly or quarterly QC routines depending on lab volume and accreditation requirements, and any time process-control standards start showing drift. The verification is faster than a full re-calibration and answers "do I need to re-calibrate?" rather than performing the calibration itself.
Yes. CS-CINSTAN-VF is prepared in accordance with ISO 11171:2022 and traceable to NIST SRM 2806d. Each shipment includes a Certificate of Analysis with the certified counts at 4, 6, 14, and 21 µm(c) particle sizes. Production dates are printed on each bottle.
24 months from production date, with a minimum of 12 months remaining when the customer receives the product. Production dates are printed on each bottle. The pack contains 4 × 400 mL bottles.
Yes. CINSTAN-VF is a NIST SRM 2806d-traceable secondary standard prepared per ISO 11171:2022 — that’s the universal verification standard for optical particle counters in oil-analysis labs, regardless of instrument manufacturer. Labs running PAMAS, KLOTZ, Hiac, or other counters use CINSTAN-VF the same way they use CINRG-line counters.
4 × 400 mL bottles, NIST SRM 2806d-traceable, with Certificate of Analysis.
Tell us about your throughput, your test methods, and your facility. A CINRG engineer will help you scope the right configuration — and put you in touch with your nearest dealer.