Calibration at 24C of a Heat-Flow-Meter Apparatus Having 610 mm Square Plates

摘要

Results are summarized for 38 individual calibration measurements conducted at 24 C and atmospheric conditions for a heat-flow-meter apparatus having 610 mm square plates. The apparatus was calibrated using a 26.2-mm-thick specimen of fibrous-glass board having a density of 139 kg/cu m. The specimen was selected from an internal lot (Lot 1970) of Standard Reference Material (SRM) similar to SRMs 1450, 1450a, and 1450b. Values of apparent thermal conductivity were predicted using a regression equation developed for the lot of fibrous-glass insulation. Calibration measurements varied + or - 0.4% with small drift of 0.4% over 250 days. The apparent thermal conductivity of the calibration specimen was also measured using the National Institute of Standards and Technology's one-meter Line-Heat-Source Guarded Hot Plate. Agreement between measurements of thermal conductivity of the guarded hot plate and predicted values were within +0.2 to -0.3% at 24 C. The report describes the heat-flow-meter apparatus and the computer data-acquisition-system used to collect data from the apparatus.