ISE 311: Ergonomics & Work Measurement
Work Evaluation Laboratory
(Due: Wednesday, March 18, 2009)
Purpose:
Through this lab, you should gain an understanding of two different tools for evaluating physical work. Specifically, you will gain experience in the following areas:
a) Using RULA (Rapid/Repetitive Upper Limb Assessment) methodology to evaluate an assembly task and make recommendations.
b) Using the NIOSH lifting guidelines to analyze single and multiple lifting tasks and make recommendations.
You should also gain some insight concerning the appropriate use of these tools for a variety of tasks, as well as insight into the assessment of worker exposure to job risk factors of posture, force, muscle use, and repetitive movement.
Procedure:
PART A: RULA Analysis
1. With the RULA template in place, place the parts of the disassembled flashlights (in bins) in their assigned positions.
2. The assembly person should assemble the flashlights, one at a time, while the observers watch and fill in the appropriate scores on the RULA Worksheet provided in the appendix.
NOTE: The RULA observers should not attempt to score the task until he/she has observed it for several repetitions, as it will take a number of repetitions to accurately observe the procedure. In general, the assembler should complete one complete set of flashlights before the observers begin to score the task. If necessary, observers can request additional assembly.
3. After the flashlights are assembled, the RULA observers will record the posture scores and note frequency and force requirements of the task.
4. Once all data is recorded, repeat steps 1-3 with the other assembler.
5. Complete the analysis to find the Grand Score for this task for each assembler. Evaluate the result (where are the “trouble” spots in the design, what are the drivers for the intermediate and grand scores, etc.)
6. Use the ErgoIntelligence-UEA program OR your ERGO software to analyze this task.
7. Recommend any necessary design changes. Perform a RULA analysis of your recommended design.
PART B: NIOSH Lifting Guidelines
1. Open the ErgoIntelligence-MMH program. Open a NIOSH single task analysis as follows: Click in the gray area of the screen. Fill in the job group information (at a minimum, put your name as the analyst and a descriptive title for the job name.) Click on the “Task Group Info” tab, then “Add Group” and enter the group duration (leave the “group performed” tab set at 5 days per week.) Click on “Add Task” (you may give the task a name, or leave it as is) and be sure “Lifting” is selected. Finally, select “NIOSH Single Lifting” on the left of your screen and fill in the information. Print your results.
2. Analyze the NIOSH lifting problem from your homework using the MMH program. Compare the results of the analysis with your results.
3. Now analyze the following task ("Loading Supply Rolls", from Applications Manual for the Revised NIOSH Lifting Equation, retrieved on February 23, 2005 from http://www.cdc.gov/niosh/94-110.html) using the MMH program.
"With both hands directly in front of the body, a worker lifts the core of a 35-lb roll of paper from a cart, and then shifts the roll in the hands and holds it by the sides to position it on a machine, as shown in [the figure.] Significant control of the roll is required at the destination of the lift. Also, the worker must crouch at the destination of the lift to support the roll in front of the body, but does not have to twist."
A job analysis worksheet was used to collect data on the job and the completed sheet is provided in the appendix.
Figure 1. Loading Supply Rolls
4. Design a workstation for the packing task described in the following paragraph. If desired, set up the task in the lab using the boxes from the assembly line lab and use the measuring tape provided to determine horizontal and vertical distances, and estimate any angles as needed. Evaluate the task using the multi-task job analysis worksheet provided in the appendix (note: additional sheets are available if needed.)
A packer is responsible for packing 6 smaller boxes into one shipping container and sending it to final shipping. The setup is illustrated on the table in the corner of the lab. Boxes A (15 lbs) and B (18 lbs) come down a conveyor on the packer’s left at a rate of approximately 3 times per minute (note: you will want to specify height and width of the conveyors based on appropriate anthropometric measures.) Boxes C – F (each weighing 0.5 lbs) come from the packer’s right at approximately the same pace. The packer loads all boxes into the shipping container in the configuration specified (see the inside of the container), and then lifts the container to another conveyor which takes it to final shipping for wrapping and shipping. This job is performed by a single packer for about 90 minutes every afternoon.
You will need to perform the multi-task analysis for loading boxes A and B into the container, and for lifting the container to the shipping conveyor (don’t forget to include the weights of boxes C – F in the final weight of the container.)
Results:
1. Show all results of calculations using an appropriate format. Raw data and intermediary calculations should be in an appendix. (Remember - the reader should be able to understand both your results and how you got them from the body of the report, and should only have to refer the appendix to get the details.)
2. Evaluate each of the tasks you have analyzed and provide specific and useful recommendations to management concerning design of the task, methods, tools, and environment. Consider both "high-tech" and "low-tech" solutions. Justify all recommendations.
Conclusions:
1. Summarize the risks associated with the jobs you have evaluated and how these risks are mitigated by your recommendations.
2. Discuss any insights you have gained from this lab with respect to job design. Your discussion should include, but not be limited to, what you observed with respect to the "let the large person fit, let the small person reach" rule.
3. Discuss the real usefulness of the NIOSH lifting guidelines and RULA analysis from an engineering design viewpoint. What benefits do they provide to an engineer in evaluating an existing job? How can they be used in the design of new jobs? (Hint: think about your design project.)
APPENDIX
Insert RULA worksheet here.
Insert REBA worksheet here.
Figure A1. Analysis Worksheet - Loading Supply Rolls
Figure A2. Multi-Task Job Analysis Worksheet
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