ISO, ASTM, and community protocols governing spectral emissivity and thermal radiation measurement.
Defines the nomenclature and wavelength boundaries for infrared spectral bands (near-IR, mid-IR, far-IR). Essential for unambiguous reporting of which spectral region an emissivity measurement covers. The standard establishes the vocabulary used across all emissivity literature when referring to wavelength ranges.
Standard test methods for total normal emittance of surfaces using inspection-meter techniques. Test Method A uses a reflectance-type meter with heated cavities as the radiation source; Test Method B uses an emission-type meter calibrated against reference standards. Both are comparative techniques; neither is an absolute method. Applicable to opaque surfaces at near-ambient temperatures. Widely used in industrial quality control for coatings and surface treatments.
Standard test method for solar absorptance, reflectance, and transmittance of materials using integrating spheres. Although focused on the solar spectrum (0.3–2.5 µm), it is frequently paired with thermal-IR emissivity measurements to characterise selective surfaces for solar-thermal applications. Defines the measurement geometry and reference standards required.
Standard test method for total hemispherical emittance of surfaces from 20 °C to 1400 °C. Uses a calorimetric technique in which a resistively heated metal strip specimen, bare or coated, radiates in a vacuum enclosure with cooled walls; the emittance follows from the electrical power balance. The method yields the total hemispherical emittance, which is the quantity needed for radiative heat-transfer calculations. Its scope is electrically conductive strip specimens and coatings applied to them, not bulk ceramics or refractories.
Practical guidance on converting directional measurements at near-normal incidence into hemispherical values, including the angular integration methods and their limitations. Authors: Adibekyan, Andersson, Arduini-Schuster, Cucchi, Hameury, Kamml, Manara, Razouk, Sprengard, Pattelli, Monte. A deliverable of the PaRaMetriC project (EPM 21GRD03), written by the participating institutes PTB, CAE, RISE, FIW München, LNE and INRIM. Published on Zenodo, 30 September 2025.
Fine ceramics (advanced ceramics, advanced technical ceramics) — measurement method for normal spectral emissivity using blackbody reference with an FTIR spectrometer. Applies to opaque ceramic specimens over 1.67–25 µm, comparing the sample's emitted spectrum with that of a blackbody reference. The 2025 edition supersedes ISO 19618:2017.
Standard practice for measuring and compensating for emissivity using infrared imaging radiometers. Essential for anyone using thermal cameras who needs to correct for the emissivity of the target surface.
Standard test method for determination of emittance of materials near room temperature using portable emissometers. The go-to standard for field measurements and rapid quality control of building and industrial materials.
Supplementary comparison of infrared spectral normal emittance/emissivity organised under the Consultative Committee for Thermometry (CCT). Pilot laboratory: NPL; participants: NMIJ, LNE, NIST, INRIM and PTB. The comparison covered 2–14 µm and 23–800 °C. Final report: Metrologia 53 (2016), Technical Supplement 03001.
What follows is a proposal for how laboratories in the network could report new spectral emissivity measurements so that they are comparable across institutions. It is a discussion document, not an adopted standard, and it is not a submission requirement of EKHI. EKHI itself stores curve-level data digitised from the published literature, held as JSON records whose provenance chain runs from the source-publication DOI to the TPRC table and curve identifier.
Spectral emissivity measurements would be traceable to a characterised blackbody reference. The proposal specifies minimum requirements for blackbody cavity geometry (effective emissivity ≥ 0.999), temperature uniformity (≤ 0.5 K across the aperture), and calibration interval. Laboratories using commercial blackbody sources would provide the manufacturer calibration certificate and any in-house verification data.
Surface condition dominates emissivity at short wavelengths and moderate temperatures. The proposal calls for documentation of surface preparation method (polishing grade, cleaning solvent, annealing history), surface roughness (Ra or Sa), and any coatings or oxide layers. For comparative studies, reference samples of known roughness could be circulated between laboratories.
Each reported dataset would include a GUM-compliant uncertainty budget. The proposal identifies the dominant uncertainty components for spectral emissivity measurements: blackbody temperature, detector non-linearity, atmospheric absorption correction, sample temperature measurement, and angular alignment.
A reported record would carry: