The need for identifying the degree of exposition to biomechanical load has led to the development of specific ergonomic risk screening analysis related to given work tasks; aim of these tools is to analyze the risk factors that may lead to overload or even occupational diseases, in order to suggest retaliatory actions that minimize the present type of risk.
The basis of every ergonomic risk screening tool is to establish a link between the three factors that determine a work task (force, frequency, grip) and the possibility to get into overload or even to contract an occupational disease because of the present working conditions and the type of task.
The main difficulty is to establish how the different factors interact and lead to work related troubles or diseases.
Figure 1 -Scheme of the new approach to risk evaluation of the EAWS
Certainly the perfect approach is to apply risk prevention in project / process design phase (preventive prospective ergonomics); if the product and/or process is already defined changes may cost more and be less efficient (corrective ergonomics) because process reorganizing is often limited due to high investments for modifications.
For a quantitative ergonomic risk evaluation of a specific working sequence, generally two evaluation levels are used:
- First level tools: risk evaluation tools which require a quick screening checklist.
- Second level tools: risk evaluation tools which require a detailed analysis with index calculations. They are applied where a possible risk has been already detected by a 1st level system.
The aim of First level tools is to get a very quick mapping of the different risk areas of all working tasks and to concentrate all the efforts for rapid redesigning. With Second level tools usually specific loads are analyzed in detail.
Though the EAWS is described as First level tool, in some sections it exceeds the detail of Second level tools (e.g. OWAS, RULA, Strain Index, HAL-TV) or is at minimum equal to them.
In the following table are summarized the risk areas, the correlated rules and some First and Second level analysis tools that cover the risk analysis for each sections. A description of the Automotive Assembly Worksheet (AAWS) is given in Schaub/Landau 2004.
Figure 2 – EAWS compatibility to International Standards and select Second level Tools