## 3 Data Collection for RERA Methodology  
The RERA methodology was used and tested on eight mechanics in a metalworking workshop. For three days, the activities performed by these mechanics were analyzed. Initially, 82 distinct activities that mechanics performed were highlighted, but following an optimization analysis regarding the evaluation of ergonomic risks, 76 activities were evaluated. The parameters of the work environment were measured with the help of sensors and entered into the database. An activity with significant risks, both regarding ergonomics and safety, is burr removal. This activity is quite frequent for the eight workers and makes ergonomic demands of them both through the awkward or forced posture that they have to adopt and through the duration of the activity, which very often exceeds 20 s for a single awkward posture. At the same time, this activity generates many contaminants (smoke, sparks, hot particles), high temperatures, and projected incandescent shrapnel. The activity is carried out with an angle grinder that weighs about 4.8 kg, requiring both hands to grip, high grip strength, and long-lasting postural demands, especially for the back, neck, and shoulders. Table 1 shows the corresponding parameters for the \"Burr removal using the (mobile) angle grinder\" activity, where L1 to L8 represent the eight evaluated workers. The characteristics of the workers are presented in Table 2.  
Figure 2: The steps of the RERA methodology. Table 1: Corresponding parameters for the \"Burr removal using the (mobile) angle grinder\" activity. \begin{tabular}{c c c c c c c c c} \hline \hline  & & \multicolumn{8}{c}{**Workers**} \\ \cline{2-10}  & **L1** & **L2** & **L3** & **L4** & **L5** & **L6** & **L7** & **L8** \\ \hline  & \multicolumn{8}{c}{Work environment} \\ Workspace & 1 & 2 & 1 & 1 & 1 & 1 & 1 & 1 \\ Temperature & 2 & 2 & 2 & 2 & 3 & 2 & 3 & 2 \\ Lighting & 1 & 1 & 1 & 1 & 2 & 1 & 2 & 1 \\ Noise & 2 & 3 & 2 & 4 & 5 & 2 & 2 & 3 \\ Dust/steam & 2 & 2 & 2 & 2 & 5 & 2 & 3 & 2 \\ \hline  & \multicolumn{8}{c}{Posture} \\ Neck & 2 & 3 & 3 & 2 & 3 & 2 & 3 & 3 \\ Shoulders/arms/hands & 2 & 2 & 2 & 2 & 2 & 2 & 2 \\ Trunk & 2 & 3 & 4 & 3 & 3 & 2 & 3 & 3 \\ Legs & 2 & 2 & 2 & 2 & 2 & 2 & 2 & 2 \\ \hline  & Work task & & & & & & & \\ Visual request & 1 & 1 & 1 & 1 & 1 & 1 & 1 & 1 \\ Manipulated masses, transport & 2 & 2 & 2 & 2 & 3 & 2 & 2 & 2 \\ Work time (Duration) & 3 & 3 & 3 & 2 & 3 & 2 & 2 & 3 \\ Psychosocial status/relationships & 2 & 3 & 2 & 2 & 3 & 2 & 3 & 3 \\ \hline  & \multicolumn{8}{c}{where the numbers 1 to 5 represent the scores obtained from each worker for the parameters of the work environment in which they carried out their activity and to which they were exposed. A lower score indicated a more favorable outcome.} \\ \end{tabular}   
Table 2: Characteristics of workers. \begin{tabular}{c c c c c c c} \hline \hline
**Workers** & **Age [Years]** & **Gender [M/F]** & **Height [cm]** & **Weight [Kg]** & **Physical Condition [Good, Athletic, Weak]** & **Experience [Years]** \\ \hline L1 & 48 & M & 171 & 88 & G & 16 \\ L2 & 36 & M & 164 & 80 & G & 11 \\ L3 & 32 & M & 178 & 77 & A & 3 \\ L4 & 51 & F & 167 & 74 & G & 8 \\ L5 & 28 & M & 182 & 95 & W & 5 \\ L6 & 31 & F & 162 & 71 & G & 3 \\ L7 & 52 & M & 175 & 98 & W & 21 \\ L8 & 51 & M & 168 & 87 & G & 17 \\ \hline \hline \end{tabular}   
Table 3: Optimal working surface height range.