SAC-SINGLAS Accreditation: What It Is, Why It Matters, and How to Verify a Laboratory

What SAC is and how SINGLAS fits

The Singapore Accreditation Council (SAC) is Singapore's national accreditation body, established under the Standards, Productivity and Innovation Board (SPRING, now Enterprise Singapore / A*STAR). SAC operates multiple accreditation programmes across different conformity assessment activities: SINGLAS (laboratories (testing and calibration), SAC-ACRA (certification bodies), ISO 9001, ISO 14001), SAC-STAR (inspection bodies), and SAC-MLA (management systems).

SINGLAS itself has two sub-programmes: testing laboratory accreditation (chemical, biological, mechanical, environmental) and calibration laboratory accreditation. Both operate under ISO/IEC 17025:2017, but the parameters, traceability requirements, and assessment focus differ. This guide focuses on calibration laboratory accreditation. The mark that matters when you need a calibration certificate to satisfy an ISO 9001, GMP, HACCP, or regulatory audit in Singapore.

SAC is a signatory to both the ILAC (International Laboratory Accreditation Cooperation) Mutual Recognition Arrangement and the APLAC (Asia Pacific Laboratory Accreditation Cooperation) MRA. These memberships mean that SAC-SINGLAS accredited certificates carry the same standing as certificates from UKAS (UK), A2LA (USA), DAkkS (Germany), NATA (Australia), CNAS (China), and IAJapan, in each other's markets, without re-calibration.

What ISO/IEC 17025:2017 requires of a calibration lab

ISO/IEC 17025:2017 is the international standard that SAC-SINGLAS accreditation verifies compliance with. Understanding what the standard demands clarifies what an accreditation assessment actually checks, and why the accreditation number on a certificate means more than a self-declaration of competence.

Organisation requirements

The lab must be a legal entity, have defined accountability for its activities, demonstrate impartiality (freedom from commercial pressure to produce biased results), protect the confidentiality of client information, and have a documented structural arrangement showing independence between technical and commercial functions. SAC assessors review these arrangements to confirm the lab can say no to a client whose instrument has failed calibration, and say it without commercial consequence.

Resource requirements

Personnel must be competent for the specific parameters they calibrate. Assessed through training records, internal authorisation, and witnessed calibrations. Facilities and environmental conditions (temperature, humidity, vibration) must be monitored and controlled where they affect measurement results. Equipment must be calibrated at defined intervals and traceable to national standards. Externally provided reference standards must be sourced from laboratories whose own traceability is verified. SAC assessors walk the floor, inspect the environmental monitoring logs, check the reference standard calibration certificates, and witness calibrations in progress.

Process requirements

The lab must formally review each calibration request to confirm it falls within scope, select validated methods appropriate to the required measurement uncertainty, maintain technical records for each measurement, and report results with full traceability and stated measurement uncertainty. ISO/IEC 17025:2017 tightened the previous edition's requirements on measurement uncertainty estimation. Every result on an accredited calibration certificate must be accompanied by the expanded uncertainty and the coverage factor used.

Management system requirements

Document control, records management, internal audit, management review, nonconformity management, and corrective action must all be in place and functioning. SAC conducts surveillance assessments (typically every 12 to 18 months), as well as full reassessments on a cycle, to verify that the management system remains effective and that technical competence is maintained between initial accreditation and reassessment.

The accreditation scope. The most important thing to check

The scope document is the heart of any SAC-SINGLAS accreditation. It defines precisely what the laboratory is accredited to calibrate and at what level of performance. A laboratory may be highly competent for some parameters and not accredited for others. The scope is the definitive boundary.

The scope lists: the specific measurement parameters (temperature, pressure, electrical (voltage, current, resistance, capacitance), dimensional, mass, torque, flow, and others); the measurement ranges within each parameter (for example, temperature: −80°C to 1200°C); the calibration methods and reference instruments used; and the Best Measurement Capability (BMC). The smallest uncertainty the lab can achieve under ideal conditions for each parameter. When a lab quotes its capabilities to a customer, those capabilities must be within the BMC published in the scope.

A lab accredited for temperature calibration is not automatically accredited for pressure calibration. If your pressure transmitter is sent to a lab whose accredited scope covers only electrical parameters, the pressure calibration certificate is not covered by the accreditation. Even if the accreditation number appears on the document. Before sending instruments, request the current scope and verify your required parameter, range, and method are explicitly listed.

Traceability chain. How Singapore connects to the SI

One of the core functions of the SAC-SINGLAS assessment is verifying the metrological traceability chain. The unbroken sequence of calibrations, each with a stated uncertainty, that connects a laboratory's working reference instruments to the internationally agreed SI units.

In Singapore, the national measurement standards are maintained by the National Metrology Centre (NMC) under A*STAR. NMC maintains primary standards that realise the SI base units. The kelvin for temperature, the ampere for electrical quantities, the pascal for pressure, the metre for length and dimension. NMC calibrates the reference standards of SAC-SINGLAS accredited laboratories. Those laboratories calibrate the instruments of their customers using those reference standards. Each step is documented in calibration certificates, with stated measurement uncertainties.

The complete chain is: your instrument → lab's working standard → lab's reference standard → NMC Singapore primary standard → SI units. When a customer in Germany, Japan, or the USA receives your product with a Singapore calibration certificate, the ILAC MRA means the entire chain is accepted without re-calibration or independent verification. That acceptance is only possible because the traceability chain has been independently verified by SAC at every level of the laboratory's operation.

How to verify a lab's SAC-SINGLAS accreditation. Step by step

Verification is free, takes under two minutes, and should be standard practice before selecting any calibration laboratory or before accepting a calibration certificate from a new supplier.

1. Go to sac.gov.sg.
2. Navigate to "Accredited Organisations" and select "Calibration and Testing Laboratories."
3. Search by laboratory name or by the accreditation number printed on the certificate.
4. The result shows: accreditation number, laboratory name, physical address, current accreditation status (current, suspended, or withdrawn), and a link to the scope document.
5. Download the scope and verify that the parameter and measurement range you require is explicitly listed.

Check the accreditation number on the certificate. A certificate showing an accreditation number that does not appear (or appears as suspended or withdrawn), on the SAC website is not a compliant accredited certificate. It should not be accepted as evidence of traceable calibration under ISO 9001, GMP, or regulatory requirements. Always verify the number, not just the presence of a logo or claim of accreditation.

What SAC-SINGLAS accreditation does not guarantee

Intellectual honesty about the limits of accreditation is as important as understanding what it asserts.

It does not mean the instrument passed. The calibration certificate reports measurements. The deviation of the instrument from the reference standard. Whether those deviations are acceptable depends on the instrument's specification or the tolerance required by your process. An accredited certificate may show an instrument that is significantly out of specification; that result is more valuable, not less, because it is trustworthy. Accreditation does not produce a pass, it produces a reliable measurement.

It does not mean every measurement from the lab is perfect. Accredited labs can make mistakes. What accreditation means is that the quality management system is structured to catch and correct mistakes, that uncertainty is properly characterised so mistakes affecting the stated result are bounded, and that an independent body has verified these systems are functioning. The uncertainty stated on the certificate quantifies the remaining doubt. It does not claim zero doubt.

Accreditation for one parameter does not cover others. This cannot be over-stated. An accredited electrical calibration does not become an accredited temperature calibration because they are on the same certificate. Read the scope before assuming coverage.

The currency of the calibration is separate from the accreditation of the lab. If a calibration was performed three years ago by an accredited lab, the accreditation of the lab at the time does not make the instrument's current state traceable. Instruments drift. The calibration certificate is evidence of the instrument's state at the date of calibration. Maintaining a calibration schedule (returning instruments within the required interval), is a separate obligation from using an accredited lab, though both are required.

Why ISO 9001 auditors look for SAC-SINGLAS

ISO 9001:2015 clause 7.1.5.2 requires that measuring equipment used to verify conformity of product and service "shall be calibrated or verified at specified intervals or prior to use, against measurement standards traceable to international or national measurement standards." The same clause requires that such equipment be "identified to determine its calibration status" and that "calibration status and subsequent recalibration dates" be preserved.

A SAC-SINGLAS accredited certificate satisfies the traceability requirement directly. The chain to NMC Singapore and thence to SI units is independently verified and documented. The accreditation number on the certificate is searchable on the SAC website, and the scope published there confirms the parameter is covered. An auditor from SGS, Bureau Veritas, TÜV, or LRQA (any body conducting third-party ISO 9001 certification in Singapore), has a clear and defensible evidence trail to accept.

A certificate from an unaccredited source may claim traceability. It cannot demonstrate independent verification of that claim. During a major ISO 9001 surveillance or recertification audit, an auditor checking clause 7.1.5.2 will look at: the certificate format (does it state uncertainty?), the accreditation number (is it verifiable?), whether the parameter is within scope (is the coverage confirmed?), and whether the calibration is current (is it within the required interval?). An unaccredited certificate frequently fails on the second check. There is no accreditation number that a third party can verify.

The ILAC and APLAC MRA. International recognition

ILAC (International Laboratory Accreditation Cooperation) is the global apex body for national laboratory accreditation bodies. Its Mutual Recognition Arrangement (MRA) is the mechanism by which member economies agree to accept each other's accredited certificates without re-testing or re-calibration. As of 2025, the ILAC MRA covers accreditation bodies in more than 90 economies representing virtually every significant manufacturing and trading nation.

APLAC (Asia Pacific Laboratory Accreditation Cooperation) is the regional equivalent for the Asia-Pacific region, and SAC is a signatory to both. The practical consequence for Singapore manufacturers and calibration customers is significant:

A calibration certificate issued by a SAC-SINGLAS accredited laboratory is accepted without further evidence in: all EU member states (through EA and national bodies such as DAkkS, UKAS, COFRAC, ACCREDIA), the USA (A2LA, NVLAP), Japan (IA Japan), Australia (NATA), China (CNAS), Malaysia (DSM), South Korea (KOLAS), Thailand (TISI), and more than 80 other economies.

For a Singapore manufacturer exporting calibrated instruments or products requiring calibration evidence to any of these markets, there is no need to arrange recalibration in the destination country. The Singapore certificate is the accepted evidence. This is not a courtesy. It is a formal, legally recognised bilateral commitment between national accreditation bodies, enforced through peer evaluation of SAC by ILAC and APLAC.

How accreditation is assessed and kept current

Accreditation is not a one-time certificate that a laboratory earns and then holds indefinitely without further scrutiny. The process begins with an initial assessment: the laboratory submits a formal application detailing its proposed scope, quality management system documentation, and evidence of technical competence, after which SAC assigns a lead assessor and one or more technical experts matched to the specific parameters being applied for. The initial on-site assessment typically takes one to several days depending on scope size, and covers document review, witnessed calibrations across a representative sample of the proposed scope, interviews with technical staff, and inspection of reference standards and their own traceability records. Nonconformities raised during this assessment must be closed out with documented corrective action before accreditation is granted, and it is common for a first application to require at least one round of corrective action before the scope is confirmed.

Once granted, accreditation is maintained through a cycle of surveillance assessments, typically conducted every 12 to 18 months, which re-examine a sample of the laboratory's activities rather than the full scope each time. A full reassessment, covering the entire scope in the same depth as the initial assessment, occurs on a longer cycle, generally every four years. Between assessments, accredited laboratories are also expected to participate in proficiency testing (PT) or interlaboratory comparison programmes relevant to their scope, where multiple laboratories calibrate or measure the same reference item and their results are statistically compared. A laboratory that consistently produces outlier results in PT programmes will face additional scrutiny from SAC, up to and including scope restriction or suspension, regardless of what its internal quality system claims. This continuous verification cycle, rather than the initial certificate alone, is what gives an accreditation number its ongoing credibility, and it is why checking a certificate's currency on sac.gov.sg at the time you receive it matters more than trusting a printed accreditation logo that may be years out of date.

When a laboratory's scope changes, or accreditation is suspended

Accreditation scopes are not static. A laboratory can apply to extend its scope (adding new parameters, wider measurement ranges, or improved best measurement capability) as its capability genuinely improves, and SAC will assess only the specific extension being requested rather than re-running a full assessment of the existing scope. Conversely, a laboratory can voluntarily reduce its scope, for example if it retires a piece of reference equipment and chooses not to replace it, or SAC can restrict a scope following a nonconformity or a poor proficiency testing result that calls a specific parameter's competence into question. This is precisely why the scope document, not the accreditation certificate's headline claim, is the authoritative reference, and why a scope check should be repeated periodically for any long-term supplier relationship rather than performed once at onboarding and never revisited.

In rarer cases, SAC can suspend or withdraw a laboratory's accreditation entirely, typically following a serious nonconformity that the laboratory fails to correct within the required timeframe, a finding of data integrity issues, or voluntary withdrawal by the laboratory itself. A suspended laboratory's certificates issued during the suspension period are not valid accredited evidence, and any customer holding a certificate issued shortly before a suspension took effect should treat it with caution and, where the measurement is compliance-critical, arrange independent verification. The sac.gov.sg lookup shows current status precisely so that this situation is discoverable rather than hidden, which is one of the clearest practical advantages accredited calibration holds over an unaccredited provider's own self-declared quality claims.