This category spans two very different uses: field thermometers for HVAC and maintenance work, and reference thermometers, dry-wells and baths for calibration laboratories.

Field instruments

Infrared thermometers are specified by distance-to-spot ratio rather than range. A 12:1 instrument measures a 25 mm spot at 300 mm; a 50:1 instrument measures the same spot at over a metre, which is what matters when the target is behind a guard.

Emissivity adjustment separates a professional instrument from a consumer one. Without it, readings on shiny metal surfaces are meaningless.

Laboratory temperature standards

Reference thermometers such as the Fluke 1523 and 1524 paired with secondary PRTs form the readout end of a calibration chain. Dry-well calibrators and micro-baths provide the stable source.

Probe condition matters as much as the readout. We inspect sheaths and connectors and state the calibration status of both parts separately.

Common questions

What is a good distance-to-spot ratio?

For general maintenance, 12:1 is adequate. For electrical inspection at distance or high-temperature process work, 30:1 or better.

Do reference probes come calibrated?

Calibration status is stated per item. Probe and readout are typically calibrated as a matched pair for best uncertainty.

Are dry-wells worth buying used?

Yes. The heating block and control electronics are durable, and calibration restores the specification.

Related categories

Process Calibrators →Thermal Imagers →Calibration & Metrology Standards →Guide: What "calibrated" actually means when buying used →

Ask about temperature instruments

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