Standard Test Method for Thermal Performance of Building Materials and Envelope Assemblies by Means of a Hot Box Apparatus, ASTM C1363 - 19

Standard that describes the principles for the design of a hot box apparatus and the minimum requirements for the determination of steady state thermal performance of building assemblies when exposed to controlled laboratory conditions.  The current version of the standard was published in 2019, and a preview of the standard can be viewed at the link with the full version being available for purchase.  There are also historical versions of this standard published in 2011, 2005, and 1997 that are available for purchase.