Polyurethane chemists have been challenged for many years to develop a laboratory scale test to measure the reactivity of polyurethane foam systems. The task is complicated by the need for the test to satisfy the requirements of both the researcher and polyurethane foamer. Numerous tests have been developed to address this task. However, the cup foam test continues to be the industry standard for quick and easy measurement of the overall reactivity of polyurethane foam systems. The characteristics of a small scale laboratory test which measures the rise profile and adiabatic temperature profile of flexible, semi-flexible (semi-rigid) and rigid polyurethane foam systems will be presented.