Frost/Dew Point Temperature and Relative Humidity Measurements: Primary and Secondary Calibration Methods

Humidity measurements are crucial across various industries to ensure product quality, safety, and process efficiency. These measurements can be expressed as absolute quantities, such as frost/dew point, temperatures point, tf/td, or as relative humidity, U, which relates to saturation at a given te...

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Main Authors: Furtado Andreia, Zenebe Fitsum, Subas Özkan, Schwinghammer Michael, Giri Praveen
Format: Article
Language:English
Published: EDP Sciences 2025-01-01
Series:EPJ Web of Conferences
Online Access:https://www.epj-conferences.org/articles/epjconf/pdf/2025/08/epjconf_cim2025_07003.pdf
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author Furtado Andreia
Zenebe Fitsum
Subas Özkan
Schwinghammer Michael
Giri Praveen
author_facet Furtado Andreia
Zenebe Fitsum
Subas Özkan
Schwinghammer Michael
Giri Praveen
author_sort Furtado Andreia
collection DOAJ
description Humidity measurements are crucial across various industries to ensure product quality, safety, and process efficiency. These measurements can be expressed as absolute quantities, such as frost/dew point, temperatures point, tf/td, or as relative humidity, U, which relates to saturation at a given temperature. Chilled-mirror hygrometers are widely used in high-precision industrial and research applications due to their broad measurement range, stability, and accuracy. Ensuring metrological traceability requires rigorous calibration using traceable methods. The DAkkS-accredited Calibration Laboratory of Process Insights follows DKD-R 5-8 [1] guidelines and meets ISO 17025 [2] requirements, employing both primary and secondary calibration methods for tf/td over the range [-90, 95] °C, and U over the range [1, 98] %rh. Primary calibration achieves the lowest uncertainties using in-house 1-pressure and 2-pressure humidity (Utf/tf : 0.4 K - 45 mK and UU: 0.10 - 0.39 %rh), while secondary calibration relies on stable CM hygrometers and commercial humidity generators (Utf/tf : 0.54 K - 70 mK and UU: 0.10 - 0.49 %rh). For relative humidity calibration, both tf/td [1] and temperature [3] sensors require calibration. Humidity calculations follow established references, ensuring high accuracy [4, 7-8]. This work outlines the methodologies and challenges in maintaining traceability and accuracy in high accuracy humidity measurements at PI Cal.
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spelling doaj-art-4b6d456e418b40fc92d2ff6a665d95cc2025-08-20T03:08:20ZengEDP SciencesEPJ Web of Conferences2100-014X2025-01-013230700310.1051/epjconf/202532307003epjconf_cim2025_07003Frost/Dew Point Temperature and Relative Humidity Measurements: Primary and Secondary Calibration MethodsFurtado Andreia0Zenebe Fitsum1Subas Özkan2Schwinghammer Michael3Giri Praveen4Process Insights GmbH, Calibration CenterProcess Insights GmbH, Calibration CenterProcess Insights GmbH, Calibration CenterProcess Insights GmbH, Calibration CenterProcess Insights GmbH, Calibration CenterHumidity measurements are crucial across various industries to ensure product quality, safety, and process efficiency. These measurements can be expressed as absolute quantities, such as frost/dew point, temperatures point, tf/td, or as relative humidity, U, which relates to saturation at a given temperature. Chilled-mirror hygrometers are widely used in high-precision industrial and research applications due to their broad measurement range, stability, and accuracy. Ensuring metrological traceability requires rigorous calibration using traceable methods. The DAkkS-accredited Calibration Laboratory of Process Insights follows DKD-R 5-8 [1] guidelines and meets ISO 17025 [2] requirements, employing both primary and secondary calibration methods for tf/td over the range [-90, 95] °C, and U over the range [1, 98] %rh. Primary calibration achieves the lowest uncertainties using in-house 1-pressure and 2-pressure humidity (Utf/tf : 0.4 K - 45 mK and UU: 0.10 - 0.39 %rh), while secondary calibration relies on stable CM hygrometers and commercial humidity generators (Utf/tf : 0.54 K - 70 mK and UU: 0.10 - 0.49 %rh). For relative humidity calibration, both tf/td [1] and temperature [3] sensors require calibration. Humidity calculations follow established references, ensuring high accuracy [4, 7-8]. This work outlines the methodologies and challenges in maintaining traceability and accuracy in high accuracy humidity measurements at PI Cal.https://www.epj-conferences.org/articles/epjconf/pdf/2025/08/epjconf_cim2025_07003.pdf
spellingShingle Furtado Andreia
Zenebe Fitsum
Subas Özkan
Schwinghammer Michael
Giri Praveen
Frost/Dew Point Temperature and Relative Humidity Measurements: Primary and Secondary Calibration Methods
EPJ Web of Conferences
title Frost/Dew Point Temperature and Relative Humidity Measurements: Primary and Secondary Calibration Methods
title_full Frost/Dew Point Temperature and Relative Humidity Measurements: Primary and Secondary Calibration Methods
title_fullStr Frost/Dew Point Temperature and Relative Humidity Measurements: Primary and Secondary Calibration Methods
title_full_unstemmed Frost/Dew Point Temperature and Relative Humidity Measurements: Primary and Secondary Calibration Methods
title_short Frost/Dew Point Temperature and Relative Humidity Measurements: Primary and Secondary Calibration Methods
title_sort frost dew point temperature and relative humidity measurements primary and secondary calibration methods
url https://www.epj-conferences.org/articles/epjconf/pdf/2025/08/epjconf_cim2025_07003.pdf
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AT zenebefitsum frostdewpointtemperatureandrelativehumiditymeasurementsprimaryandsecondarycalibrationmethods
AT subasozkan frostdewpointtemperatureandrelativehumiditymeasurementsprimaryandsecondarycalibrationmethods
AT schwinghammermichael frostdewpointtemperatureandrelativehumiditymeasurementsprimaryandsecondarycalibrationmethods
AT giripraveen frostdewpointtemperatureandrelativehumiditymeasurementsprimaryandsecondarycalibrationmethods