# Damping Rates of Anti-Vibration Gloves Made of Different Materials
## 3 Results and Discussion  
### Results of Field Measurements  
Hand-arm vibration exposures of jackhammer operators working in 3 different mines (A, B, and C) were measured 3 times with and without gloves, and the average values were compared. Overall, the vibration damping rates (%) of 12 different anti-vibration gloves  
Figure 4: Hand–arm vibration exposure measurements performed in a laboratory environment. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Glove No. **} & \multicolumn{2}{c}{**Average Values of the**} & \multirow{2}{*}{ \begin{tabular}{c} **Vibration** \\ **Vibration Exposure A Mine** \\ **A(8)\({}_{\text{avg.}}\) (m/s\({}^{2}\))** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Vibration** \\ **Damping** \\ **Rate** \\ **(\%)** \\ \end{tabular}  } & \multicolumn{2}{c}{**Average Values of the**} & \multirow{2}{*}{ \begin{tabular}{c} **Vibration** \\ **Damping** \\ **Rate** \\ **(\%)** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Average Values of the** \\ **Vibration Exposure C Mine** \\ **A(8)\({}_{\text{avg.}}\) (m/s\({}^{2}\))** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Vibration** \\ **Damping** \\ **Rate** \\ **(\%)** \\ \end{tabular}  } & \multirow{2}{*}{\ \begin{tabular}{c} **Average Values of the** \\ **Vibration Exposure C Mine** \\ **A(8)\({}_{\text{avg.}}\) (m/s\({}^{2}\))** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Vibration** \\ **Damping** \\ **Rate** \\ **(\%)** \\ \end{tabular}  } \\ \cline{2-2} \cline{6-8}  & **Ungloved** & **Gloved** & & & **Ungloved** & **Gloved** & **Ungloved** & **Gloved** \\ \hline
1 & 16.14 & 22.96 & & 11.30 & 21.31 & 10.33 & 26.79 \\ \hline
2 & 16.78 & 19.90 & & 11.58 & 19.36 & 10.62 & 24.73 \\ \hline
3 & 16.83 & 19.67 & & 11.96 & 16.71 & 10.77 & 23.67 \\ \hline
4 & 17.86 & 14.75 & & 12.07 used in each of the 3 mines were calculated. Vibration damping rate (%) is determined using Equation (3). \[\textit{Vibration}\;\textit{Damping}\;\textit{Rate}\;\left(\%\right)=\left(\left( \left(A(8)_{ungloved}-A(8)_{gloved}\right)/A(8)_{ungloved}\right)\times 100\right) \tag{3}\]  
\(A(8)_{ungloved}\): Daily personal vibration exposure measured without wearing gloves (m/s\({}^{2}\)). \(A(8)_{gloved}\): Daily personal vibration exposure measured with wearing gloves daily (m/s\({}^{2}\)). Ultimately, glove No. 1 exhibited the highest damping rate, and glove No. 12 exhibited the lowest damping rate (Table 3). [PERSON] [10] found the exposure level to frequency-weighted hand-arm vibration in the frequency range of 6.3-1250 Hz to be 25 m/s\({}^{2}\) when a jackhammer was operated in mining conditions. [PERSON] et al. [8] reported that vibration acceleration levels as high as 31 m/s\({}^{2}\) were measured for pneumatic hammers and jackhammers operated at a gold mine in the Republic of South Africa. Herein, the hand-arm vibration exposure level of the jackhammer was 20.95 m/s\({}^{2}\) at mine A, 14.11 m/s\({}^{2}\) at mine B, and 14.36 m/s\({}^{2}\) at mine C.  
Figure 5 shows the vibration exposure values of the jackhammer operators in mines A, B, and C, measured without gloves. The ungloved vibration exposure was higher in mine A than in mines B and C. The ungloved vibration exposure values may be similar at mines B and C because the same type of mineral (lead-zinc) is produced. The Regulation on Occupational Health and Safety in Mining Workplaces includes guidelines for the \"Regulation on the Protection of Employees from Vibration-Related Risks\", which should be consulted to reduce employees' exposure to vibration. In the regulation guidelines, the daily exposure limit and exposure action values are 1.15 m/s\({}^{2}\) and 0.5 m/s\({}^{2}\) for whole-body vibration and 5 m/s\({}^{2}\) and 2.5 m/s\({}^{2}\) for hand-arm vibration [20]. According to the vibration exposure measurements conducted in the field without gloves, the vibration exceeds the limit values specified in the regulation at all 3 mines (Figure 5).