Aircraft rescue and firefighting vehicle manufacturer Rosenbauer recently introduced a new input-based foam proportioning test system to market, a feature of the FIXMIX 2.0E foam proportioning system. In November of 2020, researchers at the William J. Hughes Technical Center in Atlantic City, NJ evaluated the accuracy of the of the input-based foam proportioning feature of the FIXMIX 2.0E through a comparative analysis of both input- and output-based foam testing. Two test series were conducted to evaluate the accuracy of the system: one output-based series in accordance with the procedures of National Fire Protection Association 412, “Standard for Evaluating Aircraft Rescue and Fire-Fighting Foam Equipment;” and one input-based series following the manufacturer’s procedures. Three discharges, a handline, a high reach extendable turret, and a bumper turret, were used in both test series, with each discharge representing a flow rate range. For the output-based test series, samples of the discharged foam solution were collected and measured to determine the solution concentration. For the input-based test series, the values were recorded as reported through the FIXMIX 2.0E system. Overall, output-based test results displayed a greater spread of proportioning rates compared to input-based tests. The input-based test results were generally within the defined error range of the output-based results, indicating an acceptable correlation between test methods. The FIXMIX 2.0E proportioning system accuracy appears consistent or slightly more accurate with a previously evaluated and approved onboard input-based test system. These results indicate the FIXMIX 2.0E input-based proportioning test system is an acceptable alternative to output-based testing.

DOT/FAA/TC-TN21/47 Author: Jeremy Casey