What ISO/IEC 17025 Means for Your Certificate

"ISO/IEC 17025 accredited" and "SAC-SINGLAS" are phrases you'll find on almost every calibration certificate issued in Singapore. Most people read them as "this lab is certified, everything's fine." The reality is more specific, and the gap between what people assume and what the standard actually says is exactly where audit findings, rejected certificates, and invalid measurements come from.

What ISO/IEC 17025 Actually Is

ISO/IEC 17025:2017 is the international standard for the competence of testing and calibration laboratories. It was published by ISO and IEC in late 2017, replacing the 2005 edition, and it covers two things: the technical competence of the lab (staff, equipment, methods, traceability, uncertainty) and the management system that supports that competence (document control, internal audits, corrective actions, impartiality).

The standard is organised around clauses covering general requirements, structural requirements, resource requirements, process requirements, and management system requirements. For anyone receiving a calibration certificate, the clauses that matter most are 6.4 (equipment), 6.5 (metrological traceability), 7.6 (measurement uncertainty), and 7.8 (reporting of results).

Accreditation vs Certification — Why the Distinction Matters

These words get used interchangeably, but they mean different things:

• Certification usually refers to ISO 9001 or similar quality management system certificates. It says the organisation follows a documented process. It does not say the organisation is technically competent to perform any specific measurement.
• Accreditation under ISO/IEC 17025 is stricter. It says the lab has been independently assessed as technically competent to perform specific measurements, within specific ranges, with specific stated uncertainties. Accreditation is granted against a defined scope — and anything outside that scope is not covered.

An ISO 9001 certified calibration company is not the same as an ISO/IEC 17025 accredited calibration laboratory. Only the latter can issue calibration certificates that carry the accreditation mark.

What SAC-SINGLAS Does

SAC-SINGLAS is Singapore's national accreditation body for laboratories. It's operated by Enterprise Singapore (formerly SPRING Singapore) and follows ISO/IEC 17011, the international standard for accreditation bodies. When a Singapore calibration lab displays "SAC-SINGLAS accredited," it means SAC assessors have audited the lab — typically every year for surveillance and every four years for full reassessment — and confirmed it meets ISO/IEC 17025:2017 for the specific calibrations listed on its scope.

Each accredited lab is assigned a unique identifier (for example, UT Metrology is LA-2022-0800-C) and issued a published scope document listing every parameter it is authorised to calibrate, the measurement ranges, and the best measurement uncertainty (called Calibration and Measurement Capability, or CMC).

The ILAC MRA — Why Singapore Certificates Work Worldwide

SAC-SINGLAS is a signatory to the ILAC Mutual Recognition Arrangement. ILAC (International Laboratory Accreditation Cooperation) runs a peer-evaluation process in which accreditation bodies around the world agree to recognise each other's accreditations. Because SAC is a signatory, a calibration certificate issued by a SAC-SINGLAS accredited lab is accepted by regulators, customers, and auditors in every other ILAC MRA signatory country — including the EU, US, UK, China, Japan, Korea, Australia, and most of Southeast Asia.

This matters for Singapore exporters. A product shipped to a customer in Germany, calibrated and tested with SAC-SINGLAS accredited equipment, does not need re-testing or re-calibration at the destination. The certificate is recognised as if it were issued locally.

What a Proper 17025 Certificate Looks Like

Clause 7.8 of ISO/IEC 17025:2017 specifies what must appear on an accredited calibration certificate. The essentials:

• Name and address of the laboratory, and the accreditation body mark (SAC-SINGLAS) with the lab's accreditation number
• Unique identification of the certificate and each page, with total page count
• Identification of the customer and the item calibrated (including serial number)
• Date of receipt, date of calibration, and date of issue
• The method used and any deviations from it
• Environmental conditions during calibration (temperature, humidity)
• Measurement results with stated measurement uncertainty and coverage factor (usually k=2 for approximately 95% confidence)
• A statement of traceability to SI units
• Name and signature of the authorised signatory

If any of these elements is missing, the certificate is not a compliant 17025 output and should be questioned.

What Accredited Labs Cannot Do

Accreditation has boundaries. A SAC-SINGLAS accredited lab cannot issue an accredited certificate for:

• A parameter or range outside its published scope (even if the lab has the equipment to perform the measurement)
• A measurement performed with better uncertainty than the lab's CMC value
• Work performed by staff who are not listed as approved signatories or have not been deemed competent for that specific calibration

When a lab does work outside its scope, it can still issue a report — but the accreditation mark must not appear on it. Anyone relying on the accreditation for audit or regulatory purposes should always confirm that the specific calibration is on the scope.

How to Verify a Singapore Calibration Lab

1. Ask for the lab's SAC-SINGLAS accreditation number (format: LA-YYYY-XXXX-X).
2. Confirm the lab is currently listed on the SAC-SINGLAS directory, and request the current issue of the scope document.
3. Check that the parameters, ranges, and uncertainties you need are on the scope.
4. Confirm the signatory on your certificate is listed as an approved signatory for that scope.

This takes about ten minutes and can save you weeks of rework if an auditor later rejects an improperly issued certificate.

UT Metrology's Accreditation

UT Metrology Pte Ltd is accredited by SAC-SINGLAS under ISO/IEC 17025:2017 (accreditation number LA-2022-0800-C, Issue 5, valid until 19 January 2030). Our scope covers dimensional, mechanical, temperature, and time/frequency calibration across 40+ instrument types. You can view our full accredited scope on our website, and we're happy to provide the full scope document on request for any tender or audit documentation.