Experimental research on the pneumatic extinguishers based on vibration characteristics and vibration transmission along human arm

The vibration from pneumatic extinguishers has great impacts on the health of operators. In order to optimize the design for more rational use, we analyzed the vibration spectrum of two portable pneumatic extinguishers 6MF-30 and HB2302, as well as the vibration transmissibility of human arm through experiments. It was illustrated that the fundamental frequency of 6MF-30 was 58.5 Hz, and 121.5 Hz for HB2302; there were five and two dominant frequencies separately in the range of frequency spectrum, and the higher the fundamental frequency was, the less impacts they imposed on operators. According to ISO5349—2001, the time for operators to use the two types of extinguishers at the rotation speed with maximum power before they have risk of vibration diseases was 2.29 and 3.27 years, respectively. In addition, the vibration had little influence on the operators’ shoulders and arms since the vibration acceleration values at the upper arm were quite small, and most of the vibration energy was absorbed by the palm and fingers. It is necessary to research on strategies of reducing vibration to human hand in the future.