---
title: "ASTM D4230"
url: "https://mat-cs.com/astm-d4230"
description: "This test method covers the determination of the thermodynamic dew- or frost-point temperature of ambient air by the condensation of water vapor on a cooled surface."
---

ASTM Standard

# ASTM D4230

Standard Test Method for Measuring Humidity with Cooled-Surface Condensation (Dew-Point) Hygrometer

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## Significance and Use

5.1 Humidity information is important for the understanding of atmospheric phenomena and industrial processes. Measurements of the dew-point and calculations of related vapor pressures are important to quantify the humidity information.

## Scope

1.1 This test method covers the determination of the thermodynamic dew- or frost-point temperature of ambient air by the condensation of water vapor on a cooled surface. For brevity, this is referred to in this test method as the condensation temperature.

1.2 This test method is applicable for the range of condensation temperatures from 60°C to −70°C.

1.3 This test method includes a general description of the instrumentation and operational procedures, including site selection, to be used for obtaining the measurements and a description of the procedures to be used for calculating the results.

1.4 This test method is applicable for the continuous measurement of ambient humidity in the natural atmosphere on a stationary platform.

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.