Williams, R G; Ballard, G (2003) Validation of the NPL rotatable wall guarded hot box with horizontal heat flow. NPL Report. CBTLM 25

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Abstract

This report describes measurements carried out to validate the NPL Rotatable wall-guarded hot-box apparatus. The measurements have all been carried out with vertically mounted test elements – that is with horizontal heat flow. The apparatus will be validated with non-horizontal heat flow at another time.
The validation measurements reported were carried out with a 150 mm thick expanded polystyrene (EPS) test element as well as measurements made on 20 mm thick and 60 mm thick glazed calibration panels, which were measured mounted in a 150 mm EPS surround panel, as specified in EN ISO 12567-1 and prEN 12567-2.
The measurements have been designed to show that the apparatus complies with the requirements of EN ISO 8990:1996 and EN 1946-4:2000 and so the requirements of these standards are shown in this report with appropriate data relating to the operation of the rotatable hot box.
The measurements show that the Rotatable wall guarded hot box apparatus meets all the requirements of ISO 8990 and EN 1946-4.
The measurements also confirmed the measurement uncertainty figures that were derived from a detailed uncertainty analysis (also given in this report). The overall measurement uncertainty of thermal conductance measurements made on a homogeneous specimen is estimated to be within ± 3.6 % based on a standard uncertainty multiplied by a coverage factor k = 2, providing a level of confidence of approximately 95 %.
The overall measurement uncertainty of thermal transmittance measurements carried out following the procedures specified in EN ISO 12567-1:2000 is estimated to be within ± 5.5 % based on a standard uncertainty multiplied by a coverage factor k = 2, providing a level of confidence of approximately 95 %.

Item Type:	Report/Guide (NPL Report)
NPL Report No.:	CBTLM 25
Subjects:	Engineering Measurements Engineering Measurements > Thermal
Last Modified:	02 Feb 2018 13:16
URI:	https://eprintspublications.npl.co.uk/id/eprint/2656