Testing the shock protection performance of Type I construction helmets using impactors of different masses

Top impacts are considered essential tests to evaluate the shock absorption performance of commonly used type I industrial helmets. Currently, there are two major test standards that are widely applied in helmet industry: ANSI/ISEA Z89.1 and EN397. Since drop impacts are performed using different impactors and at drop heights, results obtained using different test standards are not directly comparable. The purpose of the current study is to evaluate and compare the helmet impact test results obtained using these two frequently used helmet test standards. A representative basic Type I construction helmet model was selected for the study. A total of 19 drop impact tests were performed at different drop heights and with two different impactors (3.6 kg and 5.0 kg). Group (a) contains 10 drop impacts performed using the 3.6 kg impactor at drop heights from 0.31 m to 1.93 m. Group (b) contains 9 drop impacts performed using the 5.0 kg impactor at drop heights from 0.22 m to 1.32 m. Each of the impact trials was replicated four times. Relationships between the peak impact force and the drop height for these two test groups were analyzed and compared. When the helmets were tested with potential impact energy smaller than critical values, a consistent trend for the relationship of peak impact force as a function of the potential impact energy was obtained. Our results show that our previously proposed quantitative evaluation approach for industrial helmets’ shock absorption performance can be used with either the ANSI/ISEA Z89.1 or EN395 standard to quantify industrial helmets’ shock absorption performance. Furthermore, our results illustrated that the peak impact force would not be a reliable parameter to evaluate the helmets’ safety margin.