Rotatable Guarded Hot Box
The Future Of Wall Testing Capabilities
Oak Ridge National Laboratory (ORNL) operates and maintains a guarded hot box that is used to measure the thermal conductance (R-value) and thermal transmittance (U-Factor) of full size wall and window assemblies. The Rotatable Guarded Hot Box (RHGB) is unique in that the entire apparatus can be tilted so that the test specimen can be evaluated at vertical or horizontal orientations and at any angle in between. The box operates under the requirements of ASTM C 163-97.
Test assemblies are installed
into a a specimen frame which is mounted on a moveable dolly.
The specimen frame has an aperture of 13-ft long by 10-ft high.
The specimen frame/test assembly is inserted between two "clam-shell"
chambers of identical cross-section. The placement of the test
wall assembly between the chambers allows the chamber temperatures
to be independently controlled, thereby creating a temperature
difference across the specimen. The chambers are designated as
the climate (cold) and metering/guard (hot) chambers. The following
photograph shows the RGHB.
The climate chamber (cold side)
is equipped with blowers and an air-conditioned system capable
of producing stable environmental conditions.