## 3 Data Collection for RERA Methodology
\begin{tabular}{c c c c c c} \hline \hline
**Workers** & **Gender** & **Height [cm]** & **Physical Condition** & **Optimal Working Surface Height Range** & **Compared with** \\ \cline{3-6}  & **min** & **max** & **69.5 cm** \\ \hline L1 & 1 & 171 & 1.00 & 71.95 & 81.95 & \(\blacktriangle\) \\ L2 & 1 & 164 & 1.00 & 68.80 & 78.80 & \(\blacktriangledown\) \\ L3 & 1 & 178 & 1.10 & 82.61 & 93.61 & \(\blacktriangle\) \\ L4 & 0.9 & 167 & 1.00 & 63.14 & 72.14 & \(\blacktriangledown\) \\ L5 & 1 & 182 & 0.70 & 53.83 & 60.83 & \(\blacktriangledown\) \\ L6 & 0.9 & 162 & 1.00 & 61.11 & 70.11 & \(\blacktriangledown\) \\ L7 & 1 & 175 & 0.70 & 51.63 & 58.63 & \(\blacktriangledown\) \\ L8 & 1 & 168 & 1.00 & 70.60 & 80.60 & \(\blacktriangle\) \\ \hline \hline \end{tabular}   
Legend: \(\blacklozenge\)—the work surface is optimal, \(\blacktriangle\)—the work surface is too high, \(\blacktriangledown\)—the work surface is too low. In general, in a production hall, parameters such as temperature, lighting, noise, dust, etc. have similar values for comparable activities. However, even within the same production hall, quite often, there are situations where these parameters can differ significantly. For example, the lighting in certain areas may be insufficient, or the noise may be stronger if the worker is near a noisier machine or near some activities that produce loud noises. The ambient temperature may also vary significantly, especially near entrance doors that frequently open, creating air currents. For each activity, following the evaluation, it is determined whether the activity is carried out safely or not, an aspect highlighted in the graph in Figure 3. In this determination, the length of time during which the activity is carried out is taken into account. Time, the duration and frequency at which the worker is subjected to the identified efforts, is a determining factor, because if the duration of exposure is short, then the worker is not affected. The height of the work plans where these activities were carried out varied between 177 cm and 24 cm, and the arithmetic mean weighted by the number of measurements was about 69.5 cm. To compare this average height with the characteristics of the workers (height and gender), equation 6 was used:  
\[\mathrm{H_{SH}}=(\mathrm{H_{worker}}\times\mathrm{F+C})\times\mathrm{S}\times \mathrm{P} \tag{6}\]  
where  
\(\mathrm{H_{SH}}\)--The optimal height of the work surface;  
\(\mathrm{H_{worker}}\)--The height of the worker;  
F--Adjustment factor depending on the type of activity. In this case, the activity required force, so \(\mathrm{F=0.45}\) was used;  
C--Adjustment constant for the specific type of activity. \(\mathrm{C=\pm 5}\) cm was used;  
S--Adjustment factor for gender (S= 0.90 for women and S = 1.0 for men);  
P--The physical condition of the worker (Good = 1, Athletic = 1.10, Weak = 0.70). In this way, the table of optimal values (Table 3) for the working surface of the workers was obtained depending on the height and gender of the worker and the time of the activity. In the present case, the activity involved physical strength in the arms in particular. The values of the parameters of the ergonomic risk factors presented in Table 1 are represented graphically in Figure 4.  
Figure 3: Ergonomic risk levels obtained from the workers (L1–L8) for the studied activity. From the values represented, the parameters for the elements of the workers' body stand out, even specifically for certain workers, such as:  
* The trunk--which, depending on the height of the worker and the height of the work plane, is generally bent, rotated, and inclined;
* The work environment, in which certain elements often change quickly and significantly;
* Noise--which is generated at a high level by each worker's work equipment;
* Smoke--generated by the metal processing itself and is in close proximity to the worker who causes it. During the activity, all of these parameters have cumulative effects on the workers.