Measuring degrees of combustibility using an OSU apparatus and oxygen-depletion principle

Responding to a demand from the code writing committees for a test capable of quantitatively measuring low degrees of combustibility instead of the pass/fail of the existing non-combustibility test, the Institute for Research in Construction has developed a degrees-of-combustibility test. A version of the Ohio State University (OSU) heat release rate (HRR) apparatus, with Federal Aviation Administration modifications, has been further modified by adding an oxygen-measuring system and by reducing the airflow rate. HRR values of four sample materials have been measured, the peak rates of which ranged from 8 to 300 kW/m2. For measuring small values of HRR, an enclosed system of OSU apparatus is shown to have advantages over the open system of the cone calorimeter. In the OSU apparatus, by reducing airflow to combustion, the oxygen depletion can be increased to increase the sensitivity and accuracy of HRR measurement.