Water filters for municipality water treatment plants are assembled by stacking and rolling several pieces of membranes into a cylinder. One of the first operations in the process of assembling a cylindrical water filter is called the Prepper. This job involves pulling thin membrane sheets from large rolls of membrane, inserting netting between the membrane sheets, and transferring and stacking the membrane sheets to a tray to be used for the next operation.
Recordable musculoskeletal disorders are shown on the OSHA 300 log from the previous year. In addition, current employees performing this job completed a body part discomfort survey.
Estimates of pinch force were recorded using a pinch grip dynamometer, with pinch grips between 10 lbf and 11 lbf observed when pulling membranes from the rolls, where the employees maximum pinch grip force capability was measured as 14 lbf.
Finally, an employee questionnaire was given to several employees, with the following questions and responses from the employees:
Question: Which tasks are the most difficult to perform?
Pulling of membranes is contributing to the pain/discomfort currently experiencing
Repetitive reaching to the bottom roll
Netting location is too high, feels it in shoulder area at the end of the day
Question: Changes to the job which would reduce musculoskeletal/physical stress?
Auto-feed (auto indexing of the roll) of membranes
Lower the netting retrieval location
Utilizing the information above, using RULA (and Washington State Risk Factor Checklist – WSRFC), perform an ergonomics job analysis consisting of the following:
Ergonomic job analysis assume workers work on this job for 8 hours a day
o Identify the major tasks that the employees perform to complete this job
o Utilizing RULA (and the Washington State Risk Factor Checklist), determine if this job might need to be addressed ergonomically
o Identify specific risk factors for WMSDs (e.g., shoulder abduction, etc.) and which tasks they occur in (pictures of risk factors from video would be helpful)
o Determine if any risk factors you identified are consistent with employee discomfort feedback and WMSDs on OSHA 300 log
o Identify the root causes for the presence of the WMSD risk factors
Potential Interventions/Controls
o Identify potential engineering controls to reduce the WMSD risk factors identified utilize results from RULA (and WSRFC) analysis
o Identify the specific WMSD risk factors that will be reduced or eliminated for each potential engineering control identified
Report Grading
Professional appearance: title page, tables and pictures within report with captions, correct spelling/grammar, appendix for complete checklists (3 pts)
Introduction paragraph identifying purpose of ergonomic assessment, data and assessment methods utilized for assessment (3 pts)
Identification of major tasks employees perform to complete the job (3 pts)
Used ergonomic assessment method(s) (RULA, WSRFC) to clearly determine if exposure to WMSD risk factors elevates risk, determined need for interventions (3 pts)
Specific WMSD risk factors identified and in which major tasks they occur in (3 pts)
Determine if any WMSD risk factors identified are consistent with employee questionnaire feedback, Body Part Discomfort Survey results, OSHA 300 log entries (3 pts)
Identified root causes for the presence of WMSD risk factors (3 pts)
Identified engineering controls to reduce/eliminate WMSD risk factors identified from ergonomic assessment, utilizing results from RULA (and WSRFC) analysis (3 pts)
Identified specific WMSD risk factors each of the engineering controls identified will reduce/eliminate exposure to (3 pts)
Identified major tasks that the potential engineering controls will impact (3 pts)
Utilized employee information, survey data, in analysis/development of controls (3 pts)
Submitted completed RULA (and WSRFC) worksheets (before/after implemented controls) in Appendix
o Worksheets (RULA/WSRFC) from Initial assessment of Prepper job (3 pts)
o Worksheets (RULA/WSRFC) reflective of Prepper job after implementation of potential engineering controls (3 pts)
Figure 1. Water treatment filtering system
Figure 2. Finished membranes for water treatment filtering
Figure 3. Partially finished membrance
