Rationale part 1: It has been discussed at the last few Task Group meetings that the refractory radiant panel is no longer available and there has been a move to a non-refractory panel in a steel frame. This revision proposes to allow the new panel to be used. Rationale part 2: The purpose of this proposed revision is to clarify that the stack temperature average is to be achieved either by connecting the thermocouples in parallel or an average of the individual thermocouples. This reflects existing common practice. Rationale part 3: It has been discussed at the last few Task Group meetings that as long as the 5 minute time between conditioning and placement on the framework is followed, there is no need to place the specimen in a vapor barrier jacket.