When you send an instrument out for calibration, you get a certificate back. But a certificate is only as trustworthy as the laboratory that issued it — and that's exactly what ISO/IEC 17025:2017 accreditation is designed to establish. For Phoenix manufacturers, especially those serving aerospace, defense, semiconductor, and medical customers, understanding the difference between an accredited and a non-accredited calibration can be the difference between passing and failing an audit.
What ISO/IEC 17025 actually is
ISO/IEC 17025:2017 is the international standard for the competence of testing and calibration laboratories. It is not a product certification and it is not the same as ISO 9001. It sets requirements for a laboratory's technical competence, its measurement traceability, its uncertainty budgets, its equipment, its personnel, and its quality-management system. A lab cannot simply claim 17025 compliance — it must be assessed and accredited by a recognized accreditation body.
Accreditation body vs. self-declaration
This is the crucial distinction. Many labs say they are 'ISO 17025 compliant' or 'work to 17025.' Genuine accreditation means a third-party accreditation body — such as the International Accreditation Service (IAS), A2LA, or NVLAP — has audited the lab and issued a certificate with a specific accreditation number and a defined scope. Field Calibrations, Inc. is accredited by IAS under certificate CL-112. That number is verifiable, and the scope defines exactly which measurements the accreditation covers.
Why measurement traceability matters
An accredited calibration is traceable to the SI units through an unbroken chain of comparisons, each with stated uncertainty, leading back to national standards maintained by NIST. Traceability is what makes a measurement defensible. If your customer or a regulator asks 'how do you know this gauge reads correctly?', traceability to NIST through an accredited lab is the answer that ends the conversation.
Expanded uncertainty and k=2
Every accredited certificate reports an expanded measurement uncertainty, usually at a 95% confidence level with a coverage factor of k=2. This tells you the range within which the true value lies. A certificate without a stated uncertainty is far less useful — you can't perform a proper tolerance or guard-band analysis without it. Accreditation requires that uncertainties be rigorously evaluated and reported.
Alignment vs. certification
An important nuance: ISO/IEC 17025 accreditation establishes our competence as a calibration laboratory; it does not, by itself, mean FCI is certified to customer-industry standards like ISO 13485 or AS9100 unless separately stated in writing. What accredited calibration does is supply the traceable, documented evidence those standards require of your measuring equipment. See our alignment page for how this maps to each industry.
The bottom line for Phoenix businesses
If you supply aerospace, defense, semiconductor, medical, or government customers, accredited calibration isn't optional — it's the baseline. Field Calibrations, Inc. has provided IAS-accredited, NIST-traceable calibration from Phoenix since 1983. To verify a certificate or request our scope, contact us for a quote within one business day.