NFPA 285 refers to the NFPA 285 standard, officially titled the "Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Wall Assemblies Containing Combustible Components." It is a fire safety test developed by the National Fire Protection Association (NFPA) to assess how fire spreads vertically and laterally on exterior wall assemblies that include combustible materials, such as foam plastic insulation, certain air/water-resistive barriers (WRBs), or combustible claddings.The test simulates a multi-story fire exposure using a two-story test rig with gas burners (one inside a room and one at a window opening) to evaluate a full wall assembly over a 30-minute period. It measures flame propagation, temperature limits inside the wall, and external flame spread.