Currently, the North American standard, ANSI/APA PRG 320: Standard for Performance-Rated Cross-Laminated Timber, requires a full-scale compartment fire test to qualify adhesives for use in cross laminated timber (CLT) for structural applications. This test is necessary to determine whether the adhesives will experience heat delamination - a premature adhesive failure during fire that can lead to sudden fire regrowth during the decay phase of a fire commonly referred to as a secondary flashover. The required full-scale test is cost-prohibitive to adhesive manufacturers when developing new adhesive formulations. This paper presents work performed at the Forest Products Laboratory (FPL) focused on developing a low-cost intermediate scale test used to predict if a new adhesive formulation is likely to delaminate and, therefore, fail the full-scale PRG 320 test. In the FPL method, a 2.44 m long by 610 mm wide CLT panel is exposed to a time-temperature profile in a furnace designed to match the PRG 320 test. Additionally, the mechanical loads are scaled to target the bending moment in the PRG 320 test standard. New findings presented in this conference paper include measurements of the oxygen concentration within the furnace during the test.