Calibration FAQ Singapore: 40 Questions Answered by SAC-SINGLAS Experts

Start by listing every instrument in your facility used for quality-affecting measurements. Temperature, pressure, electrical, dimensional, or weighing. For each, note the parameter, range, and how it influences your product or service. Send that list to Unitest. Our team will advise which instruments require accredited calibration, recommend starting intervals, and sequence the first calibration run to minimise disruption to your production schedule.

Unitest holds SAC-SINGLAS accreditation (no. LA-2023-0845-C) covering electrical parameters (voltage, current, resistance, power, frequency), temperature (RTDs, thermocouples, thermometers, data loggers), pressure (gauges, transmitters, manometers), humidity, and related physical parameters. The full scope is available on our accreditation page and verifiable at sac.gov.sg. Contact us if your instrument type is not listed. We can advise on scope or refer you to an appropriate accredited provider.

Standard turnaround at Unitest is 5–7 business days for most instrument types. Priority turnaround is available on request and subject to scheduling. Instruments with complex multi-point calibrations, extended thermal soak requirements, or found-out-of-tolerance conditions requiring adjustment and re-measurement may take longer. We advise on expected turnaround at the time of receipt and will notify you promptly if any issue extends the timeline.

Yes. On-site calibration is available for instruments that cannot be removed from service or where calibration must be performed in the operating environment. Process-connected pressure transmitters, installed temperature sensors, and fixed-installation equipment. On-site calibrations are performed with portable reference standards that are themselves accredited-calibrated and traceable to NMC Singapore. Contact us to discuss instrument suitability and scheduling for on-site work.

Unitest serves manufacturers, electronics and semiconductor companies, pharmaceutical and medical device manufacturers under GMP, food and beverage producers under HACCP, marine and offshore maintenance, aerospace and defence MRO, utilities, building services contractors, and any organisation subject to ISO 9001, IATF 16949, AS9100, ISO 13485, or Singapore regulatory audit. If your quality system requires traceable calibration certificates, we have the scope, the accreditation, and the experience to serve you.

There is no formal minimum instrument count. We handle single-instrument submissions as well as fleet contracts covering hundreds of instruments. For single instruments, per-instrument handling and certification costs mean the unit price is higher than for batch submissions. We recommend batching instruments by parameter where possible to optimise turnaround logistics and overall cost. Speak to our team for pricing guidance on your specific instrument list.

Use the Request a Quote form on our contact page, or email us directly with a list of instruments (make, model, serial number, parameter, and range). We respond with a quotation typically within one business day. For large instrument lists or unusual parameters, a brief call with our technical team first will help scope the work accurately. You can also visit us at our Singapore laboratory. Contact us to arrange a visit or instrument drop-off.

It means the Singapore Accreditation Council has independently assessed the lab against ISO/IEC 17025 and confirmed its traceability chain, uncertainty calculations, equipment, and staff competence meet that standard. It is not self-declared. Assessors visit the lab and reassess it on a recurring cycle to keep the accreditation live. Unitest's number is LA-2023-0845-C.

Traceability means every reference standard used on your instrument is connected, through an unbroken chain of calibrations each with a stated uncertainty, back to Singapore's National Metrology Centre (NMC). ISO 9001 clause 7.1.5 requires it explicitly. Without a documented chain, a measurement result has no basis for trust. See our full traceability to NMC guide.

Go to sac.gov.sg, search Accredited Laboratories, and enter the lab's name or accreditation number. The listing shows whether it is current, its validity dates, and its exact scope of parameters and ranges. The check takes under two minutes and is free.

No. Accreditation is scope-specific. A lab accredited for electrical parameters may not be accredited for pressure or temperature, even if it sells that service. Always cross-check your specific parameter against the lab's published scope, not just its name.

The typical 15-30% premium covers ongoing accreditation costs: surveillance visits, periodic reassessment, proficiency testing, and the engineering time to validate a correct uncertainty budget for every method. See our full accredited vs non-accredited comparison.

Yes. SAC is a signatory to the ILAC Mutual Recognition Arrangement, so a SAC-SINGLAS certificate is recognised across all ILAC MRA member economies, including the US, EU, Australia, Japan, and China, without re-calibration.

Instrument ID (make, model, serial), calibration date, environmental conditions where relevant, measured results at each test point, stated measurement uncertainty, the reference standards used and their traceability, and the technician's signature. A certificate missing uncertainty is the single most common trigger for a clause 7.1.5 finding.

A quantified estimate of the doubt in a result, for example ±0.3°C at 95% confidence, calculated from the reference standard's own uncertainty, environmental effects, repeatability, and resolution. Without it, you know only what the instrument read, not whether that reading is fit for your tolerance.

Commonly three to seven years past decommissioning, depending on industry and regulation (GMP, medical device, and aerospace sectors often require longer). Retain certificates through any recall investigation covering the period the instrument was in use.

For ISO 9001, GMP, or any Singapore regulatory submission, an unaccredited overseas certificate has the same weakness as a local one: no independently verified traceability chain. Look for accreditation from a body that is itself an ILAC MRA signatory in that country.

"As found" is performance before adjustment, showing how far the instrument drifted since the last calibration. "As left" is performance after adjustment. As-found is the more important figure for your quality system: it tells you whether the instrument was actually within tolerance while in use.

For low-criticality use, possibly. For anything feeding an ISO 9001, GMP, or HACCP decision, a bare pass/fail gives you no drift data, no traceability evidence, and nothing an auditor can independently evaluate. Request full data certificates for quality-critical instruments.

Start conservative, typically 6 or 12 months, then adjust from the instrument's own as-found drift history over two to three cycles. Stable results support extending the interval with documented justification; drift near tolerance means shortening it. Application criticality matters too.

Yes, provided the decision is documented and based on objective evidence, typically a stable as-found history reviewed periodically. An interval extended without recorded justification is one of the two most common calibration findings we see, alongside missing uncertainty.

The instrument's accuracy from that point is technically unknown, not necessarily wrong. Quarantine it from quality-affecting use, recalibrate promptly, and if it comes back out of tolerance, run an impact assessment covering everything measured with it since its last valid calibration.

No. A blanket 12-month default without justification is itself a common finding. Stable, low-use references can often safely run 24 months with documented history; harsh-environment or tight-tolerance instruments may need 3 or 6 months. Follow the evidence, not a default.

A calibration register, spreadsheet, QMS module, or asset management tool listing every instrument, interval, last date, and due date is the minimum. Beyond roughly 50 instruments, most Singapore manufacturers move to dedicated software with automated recall alerts, since manual tracking reliably breaks down at that scale.

Generally yes, unless the manufacturer supplies a recent, valid, traceable certificate covering your required parameters. Many quality systems still require an independent initial calibration to establish the instrument's own baseline, especially for regulated or safety-critical measurements.

The instrument's as-found measurement, before any adjustment, fell outside the tolerance limits defined for its use. It is a factual finding about the instrument's state, and does not by itself tell you whether product was affected; that needs a separate impact assessment.

Open a nonconformance record, identify everything measured with the instrument since its last known-good calibration, and assess whether the drift found could plausibly have affected product conformity. Only then decide whether product needs review, rework, or recall.

Not automatically. It depends on the drift's magnitude relative to your process tolerance and how critical the measurement was. This is why a documented impact assessment, not a reflexive recall, is always the correct first step.

In most cases, yes, where the design permits it. We record as-found data first, adjust, then record as-left data confirming it is within tolerance. Both appear on your certificate. If it cannot be adjusted back into tolerance, we advise on repair or replacement.

Back to the instrument's last calibration confirmed within tolerance. This is a strong argument against extending intervals casually: a longer interval means a longer potential impact window if the instrument is later found OOT.

No. It reflects the instrument's own drift from wear, environmental exposure, or normal ageing, not a calibration error. A lab that never reports OOT results across a large fleet is more likely under-detecting than genuinely perfect.

Connected to a deadweight tester or precision pressure comparator, which applies known pressures traceable to NMC Singapore across the gauge's range. Deviation and uncertainty are recorded at each point. See our full pressure calibration guide.

Compared against a reference thermometer in a stable source, typically a dry-block, liquid bath, or furnace, at multiple points across its span. Thermal stabilisation time at each point matters significantly. See our temperature calibration guide.

A precision multi-function calibrator sources known voltage, current, and resistance across the meter's ranges, and displayed readings are compared to those known values. Environmental temperature is controlled since many electrical parameters are temperature-sensitive at the tolerances involved.

Applied to a calibrated torque transducer at multiple points across its rated range, in both directions if the tool supports it. For click-type wrenches, repeatability across repeat applications is also assessed. See our torque calibration guide.

By the sensor type built in. A temperature logger is calibrated like any temperature sensor, against known reference temperatures. Multi-channel loggers require each channel calibrated individually, since channels can drift independently.

Confirm your specific balance or scale class and range against our current accredited scope before submission. For legal-for-trade weighing, a separate statutory verification under the Weights and Measures Act may also be required.

Checked against calibrated gauge blocks or reference length standards across their range, assessing accuracy and repeatability. Environmental temperature control matters, since dimensional materials expand and contract measurably. See choosing a dimensional provider and common dimensional metrology errors.

Yes. EV charger test equipment combines electrical parameters (voltage, current, insulation resistance, RCD trip timing) within standard accredited electrical scope. See our EV charging test equipment calibration guide.

Contact us with the make, model, parameter, and range. If it falls within our accredited scope, we will confirm and quote directly. If it does not, our technical team can usually advise whether it falls under a related parameter we do cover, or point you toward an appropriately accredited provider elsewhere. We would rather refer you correctly than take on work outside our verified competence.