The fire-safety economy is measured in minutes, but built in kilograms A warehouse does not purchase “fire resistance” as an abstract promise. It purchases 30, 60, 90 or 120 minutes of structural stability. Ammonium Polyphosphate (APP) (intumescent agent) is one of the materials that converts those specified minutes into a physical barrier: under heat, the coating swells, carbonises and creates a low-density insulating char between the flame and the substrate. Commercial systems can...