Development of a System for Testing the Explosion Resistance of Portable Fire Extinguisher Cylinders Under Hydrostatic Pressure

This paper proposes a system for testing the explosion resistance of fire extinguisher shells under hydrostatic pressure, in accordance with ISO 11601:2017 standards. Due to the variability of fire extinguisher specifications, a data-driven modeling method is employed for system identification, and its fitting performance is evaluated by the Mean Squared Error (MSE) metric. Additionally, model-based incremental PI controllers are designed to strictly comply with the desired pressures while maintaining an error margin within 5%. A control strategy is proposed to address unspecified procedures in the ISO standards. To verify the pre-experimentation method, a simulation was conducted to regulate water pressure within a 5% deviation for a duration of 60 seconds in the steady phase, while also achieving a consistent pressure rise rate of (20 ± 2) bar/min during pressure increase steps. Finally, an experimental test was carried out with two types of fire extinguishers: 6 kg and 8 kg. Results indicated that the 6 kg extinguisher burst after 570 seconds with a maximum pressure of 53 bar, while the 8 kg extinguisher reached a pressure of 60.62 bar and burst after 551 seconds. Consequently, this test is crucial for ensuring the safety standards of fire extinguishers prior to certification.