International Organization for Standardization

Thermal Insulation - Building Elements - In-Situ Measurements of Thermal Resistance and Thermal Transmittance - First Edition
 N 9869

Annotation

Limits of application

This International Standard describes the heat flowmeter method for the measurement of the thermal transmission properties of plane building components, primarily consisting of opaque layers perpendicular to the heat flow and having no significant lateral heat flow.

It is not intended as a high precision method replacing the laboratory instruments such as calorimeter, hot boxes.

The properties which can be measured are

a) the thermal resistance, R, and thermal conductance, A, from surface to surface;

b) the total thermal resistance, RT, and transmittance from environment to environment, U, if the ambient temperatures of both environments are well defined.

The heat flowmeter measurement method is also suitable for components consisting of quasihomogeneous layers perpendicular to the heat flow, provided that the dimensions of any inhomogeneities in close proximity to the heat flowmeter (HFM) are much smaller than its lateral dimensions and are not thermal bridges which can be detected by infrared thermography (see 6.1 .l). For other components, an average thermal transmittance may be obtained using a calorimeter or by averaging the results of several heat flowmeter measurements.

Content of this International Standard

This International Standard describes the apparatus to be used, the calibration procedure for the apparatus, the installation and the measurement procedures, the analysis of the data, including the correction of systematic errors and the reporting format.