- Record Type:OSHA Instruction
- Current Directive Number:CPL 2.14 CH-1
- Old Directive Number:CPL 2.14 CH-1
- Title:Changes to Boston Regional Instruction, CPL 2.14, Ergonomic Inspection Instruction for the Documentation of Hazards Associated with Lifting.
- Information Date:
"This document was published prior to the publication of OSHA's final rule on Ergonomics Program (29 CFR 1910.900, November 14, 2000), and therefore does not necessarily address or reflect the provisions set forth in the final standard."
Boston Regional Instruction CPL 2.14 CH-1 March 7, 1994 Office of the Regional Administrator
SUBJECT: Changes to Boston Regional Instruction, CPL 2.14, Ergonomic Inspection Instruction for the Documentation of Hazards Associated with Lifting
A. PURPOSE. To transmit revised pages.
B. SCOPE. This instruction applies to all OSHA employees involved with ergonomic inspections in Region I.
C, ACTION. Remove pages 8, A-1, A-3, B-1, B-2 and B-8 from Boston Regional Instruction, CPL, 2.14, dated January 20, 1994, and replace with the same pages, respectively. File this transmittal sheet after the information as a record of the changes.
D. EXPLANATION OF THE CHANGES. The definition of active surveillance on page 8, the names of two musculoskeletal disorders on page A-3, and the use of term, biomechanical, on page B-1 and B-2 have been changed. In addition, several words have been changed or deleted on pages B-8 and A-1.
JOHN B. MILES, JR. Regional Administrator
Distribution: Regional Administrator, Deputy Regional Administrator, Assistant Regional Administrators, Area Directors, All Supervisors, All Employees, DLO
Boston Regional Instruction CPL 2.14 January 20, 1994 Office of the Regional Administrator
SUBJECT: Ergonomic Inspection Instruction for the Documentation of Hazards Associated with Lifting
A. Purpose. This instruction provides guidance and procedures for the case documentation of hazards involving lifting injuries. This instruction is third in a series of three regional directives on ergonomic inspection instruction. Directives CPL 2.11 and CPL 2.13 are referenced below.
B. Scope. This instruction applies Region-wide.
- 1. OSHA Publication 3123, "Ergonomics Program Management Guidelines For Meatpacking Plants", 1991.
- 2. Cumulative Trauma disorders: A Manual For Musculoskeletal Disease of the Upper Limbs. Edited by Vern Putz-Anderson, Taylor and Francis, 1988.
- 3. Bureau of Labor Statistics, Log and Summary of Occupational Illnesses and Injuries, OSHA Form 200.
- 4. OSHA Instruction CPL 2.78, "Regional Ergonomics Program", 1987.
- 5. OSHA Fact Sheet Number 89-09, "Back Injuries-Nation's Number One Workplace Safety Problem."
- 6. The NIOSH "Work Practices Guide for Manual Lifting" (NTS PB 821-789-48), 1981.
- 7. OSHA Instruction CPL 2-2.20B: OSHA Technical Manual, Chapter 5, "Back Disorders and Injuries", 1990.
- 8. Boston Regional Instruction, CPL 2.11 "Guidelines and Compliance Procedures to Evaluate and Achieve Reduction of Back Injuries", 1990.
- 9. Eastman Kodak Company, Human Factors Section. Ergonomic Design for People at Work. Volume 1: Workplace, Equipment, and Environmental Design and Information Transfer. Belmont, California: Lifetime Learning Publications, 1983. (page 340)
- 10. Chaffin, D. B. and Andersson, G. B., Occupational Biomechanics, Second Edition. John Wiley and Sons, Inc., New York, 1991.
- 11. OSHA Instruction CPL 2.98, "Guidelines for Case File Documentation for use with Videotapes and Audiotapes", 1993.
- 12. Boston Regional Instruction CPL 2.13, "Ergonomic Inspection Instruction", 1993.
- 13. Waters, T.R., Putz-Anderson, V., and Garg, A., Applications Manual for the Revised NIOSH Lifting Equation, (in press), 1993.
D. Background. Preventing back injuries is a major workplace safety challenge. According to the Bureau of Labor Statistics (BLS), back injuries account for one of every five workplace injuries and illnesses. In fact, one- fourth of all compensation indemnity claims involve back injuries, costing industry billions of dollars in addition to the pain and suffering borne by employees. According to the BLS, four out of five injuries associated with manual materials handling tasks (placing, carrying, holding, lowering and lifting) are to the lower back and three out of four occur while the employee is lifting. Although no approach has been found for totally eliminating back injuries caused by lifting, risk can be significantly lowered and the severity of the injuries can be reduced with an effective control program that includes the ergonomic design of work tasks.
- Most recently, the NIOSH Practices Guide for Manual Material Handling has been revised to reflect new research findings and to provide for asymmetrical lifting tasks as well as objects with less than optimal hand-container couplings. The more recent guidelines have been referred to as "The NIOSH Revised Lifting Guidelines." Holland has already incorporated these new guidelines into their manual material handling directive. Both the 1981 and revised NIOSH guidelines, in addition to other methods, will be used to establish that employees are exposed to lifting hazards that could cause serious physical harm. Other methods that may be used for case documentation include psychophysics, physiology, biomechanics, kinematics and epidemiology. Copies of the NIOSH Revised Lifting Guidelines have been distributed to all area offices in Region I. In addition, other methods are discussed in further detail below and in appendices B (The Peak Performance System) and C Psychophysical Scales). The Regional Ergonomist will provide assistance with the use of tools for other methods of case documentation as needed.
- It is noteworthy to state that inspections that require the above methods of documentation require substantially more time than inspections that encompass hazards for which standards exist. It is recommended that teams be used, where possible, to document exposures. This is especially true for lifting tasks that are highly variable and frequent in nature (i.e., warehouses, health care facilities and distribution operations) or highly variable and infrequent in nature (i.e., construction, sawmills and maintenance operations).
E. Technical Assistance. In accordance with OSHA Instruction CPL 2.78, dated February 9, 1987, technical assistance for ergonomic related material will be provided from the Regional Ergonomist. Assistance from the OSHA Salt Lake City Technical Center and/or the National Office should be requested only after consultation with the Regional Ergonomist. This will ensure that the appropriate data is collected for the analysis of lifting hazards, and that technical assistance is used in the most effective and expedient manner.
F. Action. In order to support a 5 (a)(1) violation, the criteria in the FOM must be met and the following additional information shall be provided.
- 1. Calculation of Incidence Rates.
- The incidence rate of lifting related injuries include the number of cases that come into existence during a specified time period, usually one year, for a specified population (i.e., entire plant, one department, jobs with similar exposures, similar tasks, etc.). Injuries include incidents that are related to specific events, such as lifting a 50 pound sack of dog food. Although, there is evidence that injuries related to lifting are actually related to cumulative trauma, this directive will utilize the OSHA 200 reporting guidelines with respect to back injuries.
- According to the BLS recordkeeping requirements, injuries are recordable only when they require medical treatment, or involve loss of consciousness, restricted work or motion, or a job transfer. The reaggravation of a previous injury almost always results from some new incident involving the employee (such as slip, twist, trip, extended reach, etc.). Consequently, when work related, these new incidents should be recorded as new cases. Examples of lifting related injuries include any sprains (ligament damage that occurs at a joint such as the shoulder or knee), strains (muscle and/or tendon injury), neural and/or neuromuscular related injuries (sciatica, thoracic outlet syndrome), and/or bone related injuries (a "herniated disc," fractured vertebra). Injuries associated with lifting can occur anywhere in the body, including the lower extremities, upper extremities, the back and the abdominal region. When feasible, Medical Records, first reports of injury, and employee/employer interviews shall be used to validate that the injury is related to a workplace exposure.
- a. Incidence rates for lifting related injuries shall be calculated for each year during the past five years (or less if the company or process is less than five years old). The information shall be used to analyze the trend of the incidence and severity of back injuries prior to performing an analysis of the workplace hazards and prior to consulting with the Regional Ergonomist.
- b. The minimum information required for calculating incidence and severity rates shall be:
- (1) Total number of new incidences (cases) (2) The date each incidence (case) was reported (3) The department (or specific job) of the worker (4) The number of workers in the same risk group for which the incidence rate will be calculated.
- (5) The number of workers in the entire facility (6) The number of days of restricted work activity (7) The number of days away from work
- c. An incidence rate shall be calculated for the entire facility. This number may be higher than the Lost Workdays Incident Rate (LWDI) that is required on the OSHA 1A form, since lifting injuries without lost days will be included in the calculation. An incident rate shall also be calculated for specific groups of workers when all ergonomic stressors (weights, heights of lifts, frequency of lifts, hand-load coupling, temperature, and material lifted) within each group are similar.
- d. The formula used to calculate incidence rate (IR) is described in the book, Cumulative Trauma Disorders: A Manual for Musculoskeletal Disorders of the Upper Limbs, located in each area office. For convenience, the formula is provide below:
- IR = ----------------------------------------------
- The total hours represent the total number of hours worked by employees in a general or specific group.
- The number 200,000 represents 100 full time workers so the resulting incidence rate is interpreted as the number of incidents per 100 workers. This normalization of the data allows for the comparison of incidence rates between different sized groups. If it is not possible to obtain the actual number of hours worked, then a denominator of (the number of full-time workers X 2000) may be used to calculate the incidence rate. Note that the injuries do not have to involve lost workdays to be included in the formula.
- e. Incidence rates for the entire facility will be compared with the incidence rate for a specific group of interest, unless the group of interest represents a majority of the entire facility. In the latter case, refer to section F. 1. f. A hazard that could cause serious physical harm may exist if the incidence rate for the specific group of interest is significantly higher than the incidence rate for the entire facility. The calculation and comparison of incidence rates may also be used to determine which tasks, jobs or departments have the greatest risk for the development or musculoskeletal injuries related to manual material handling.
- f. Additional factors, such as those listed below, will have to be considered in order to substantiate the evidence of employee harm where the number of workers in a facility or a specific group is small. The Regional Ergonomist can assist with the epidemiology (the study of disease) in these cases.
- Additional factors that shall be used to document that employees were exposed to serious physical harm include severity, trend, employee transfer requests and employee turnover rates. Severity and trend are discussed below.
- (1) Severity
- Severity is a statistic that aids in the description of the seriousness of the hazard for a facility or a specific group of workers. Severity (S) can be calculated as follows:
- Number of lost workdays X 200,000 S = ---------------------------------
- If available, the actual number of hours worked by employees may be used in lieu of (Number of employees X 2,000) in the equation above.
- Comparisons may be made with the severity rate for injuries for a specific industry (data may be available from the BLS through the Regional Ergonomist) or comparisons may be made internally. For example, an internal comparison could be made between the severity rate for a specific department and the severity rate for the entire facility.
- Severity statistics attempt to describe the seriousness of the injuries that have occurred. They may be used to substantiate medical mismanagement since the longer symptoms remain unreported, the more severe they may become. In one case, a CSHO utilized the increasing trend in severity rates of night bakers to substantiate workers' comments that symptoms were not reported when they first occurred.
- (2) Trend
- Trend is used to look at the pattern of risk over time. Five years will be used to identify trends of incidence and severity, when the records exist.
- A gradual increase in the incidence rate over five years and/or a more marked increase in the incidence rate as a result of changes to equipment and/or processes may indicate that a hazard exists. This information may also be used to show, that with reasonable diligence, the employer should have known that a hazard existed. Please be aware that increased employees's awareness of hazards may increase the incidence rate of injuries over time. However, it is expected that the severity rate should decrease in a relative manner because symptoms are reported and responded to at their onset, before they become severe. For example, a warehouse selector may incur "a sharp pain" in his/her lower back, but does not report the pain until it is so severe that several lost workdays are incurred. Sharp increases in incidence rates may also follow the termination of games such as "safety bingo" or other systems that discourage the reporting of injuries.
- 2. Surveying the workers
- a. All workers at a facility should be surveyed by the CSHO to determine if the incidence reported on the OSHA 200 log represents the actual incidence of lifting related injuries and illnesses. In the event that the number of employees is too large to allow for interviews, questionnaires may be completed independently by the employees. In such cases, individual envelopes should be offered to employees to ensure confidentiality. Once completed, surveys can be mailed directly to the area office or picked up at a predetermined location on a specific date by the CSHO. These methods of surveying are referred to as active surveillance. Active surveillance also includes physical examination performed by a health care professional. In cases where the employer fails to recognize that the exposures and health outcomes are work related, it will be necessary to request assistance from the Regional Ergonomist for active surveillance. Under a planned agreement with physicians from Yale's, Harvard University's and The University of Massachusetts at Worcester's Occupational Medicine Residency Programs, this assistance will be available upon request for certain area offices.
- The literacy of workers should be taken into consideration during active surveillance. In any case, interviewers will show impartiality to avoid "interviewer bias"; questions shall not be "leading." For example, a question such as, "Doesn't your back hurt from all of that lifting?" should be avoided. All questions should be standardized such as those in Appendix A. In general, at least 75 percent of the population under study should be interviewed so that the sample is representative of the study population. Failure to do so, in small cases, may invalidate the results of the worker surveys. However, random sampling may be used for large populations. The Regional Ergonomist is available to provide area offices with assistance in making this statistical determination.
- b. Appendix A provides a sample of a valid symptom survey. OSHA publication 3123, "Ergonomic Program Management Guidelines for Meatpacking Plants," page 16 and 17, also provides an example of a valid symptom survey. Either may be used, however page 17 of OSHA publication 3123 must be replicated for each area where symptoms exist (i.e., one for the shoulder, one for the back, etc.). Failure to do this invalidates the survey.
- 3. Videotaping
- a. All work that is analyzed for ergonomic stressors will be videotaped.
- b. A written narrative will accompany the video with the following information provided:
- (1) The weights of materials handled. This information is usually available from the employer via scheduling forms, manifests or inventory schedules.
- (2) A rough sketch of the facility and process flow. This is usually available from an industrial engineer or production manager.
- (3) The scheduling of tasks, (ie., variable, constant, rotation, full time, part time, etc.).
- (4) The dimensions of the materials handled and the location of handles or cut-outs that provide for handling of the material.
- (5) The heights of applicable work surfaces and reach distances.
- (6) The names of tasks, jobs and departments in the order that they appear on the video.
- (7) Any other relevant information pertaining to the inspection
- The narrative may be recorded directly onto the video provided that the surrounding noise level allows for conversation with another person approximately four feet away. This rule of thumb will assure that your voice is audible on the video.
- c. The OSHA Technical Manual, Boston Regional Instruction 2.13, dated January 3, 1993, and OSHA Instruction CPL 2.98, dated October 12, 1993, provide guidelines for video taping.
- (1) In order to videotape for a "Peak Performance System" evaluation (a combination of biomechanic and kinematic methods of analysis), additional constraints exist. A description of the Peak Performance System, which can be used to evaluate biomechanical stressors across time, is provided in Appendix B. In addition, a short video tape on the use of the Peak Performance system has been provided to each area office. The Regional Ergonomist will provide assistance with the use of the peak performance analysis.
- 4. Checklists for OSHA investigations involving hazards associated with lifting.
- a. Data from the technical manual, the Regional Ergonomist and other sources may be used to construct a checklist for the inspection. Checklists may be different for various industries. For example, adequate staffing for the performance of safe lifts, assists and transfers may be of concern in extended healthcare facilities, whereas the appropriate placement of product may be of greater concern in a food warehouse. The Regional Ergonomist can provide assistance with the construction of a checklist. An example of checklists that might be used to gain specific information such as the estimation of physical exertion during specific tasks, are provided in Appendix C.
- 5. Citation language and requests for assistance from the Regional Ergonomist
- a. Information from the OSHA Technical Manual, the Regional Ergonomist and other sources will be used to construct a 5 (a)(1) letter and/or citation, when warranted. Model lifting citation language is offered in CPL 2.11, dated May 22, 1990, "Guidance for Compliance Procedures to Achieve Reduction of Back Injuries."
- b. In all cases, a full size, VHS videotape with the approximate length of the tape noted and the statistics explained above will be submitted to the Regional Ergonomist when technical assistance is needed and before a citation is issued. Ergonomic inspections that result in a letter of significant findings do not require review by the Regional Ergonomist, although assistance is available upon request.
JOHN B. MILES, JR. Regional Administrator
Distribution: Regional Administrator, Deputy Regional Administrator, Assistant Regional Administrators, Area Directors, All Assistant Area Directors, All Compliance Officers, Directive Liaison Officer.
Surveying the Worker
OSHA publication 3123 contains a similar survey and may be used in lieu of the survey below. Either may be used, however, Page 17 of OSHA publication 3123 must be replicated for each area where symptoms exist (i.e., one for the back, one for the right knee, etc.). Failure to do this may invalidate the survey.
Name:___________________________ Job position:___________________
Years in present position:__________ Years with company:_________
Home Phone number:( )__________________
Age______ Weight_______ Height_______ Sex______
Mark the appropriate place on the discomfort scale (from none to unbearable):
1. Within the past month, have you had repeated feelings of numbness, tingling or "pins and needles" sensations in:
- Right hand (0)none________________________(10)unbearable Right leg (0)none________________________(10)unbearable Left hand (0)none________________________(10)unbearable Left leg (0)none________________________(10)unbearable
- If a date and place of injury is known, please note this information in the margin next to the body part marked above. To whom did you report the injury? Name/position____________
2. Within the past month, have you had repeated feelings of soreness or pain?
- Right elbow (0)none________________________(10)unbearable Right forearm (0)none________________________(10)unbearable Right knee (0)none________________________(10)unbearable Right ankle (0)none________________________(10)unbearable Left elbow (0)none________________________(10)unbearable Left forearm (0)none________________________(10)unbearable Left knee (0)none________________________(10)unbearable Left ankle (0)none________________________(10)unbearable
- If a date and place of injury is known, please describe in the margin next to the body part marked above. To whom did you report the injury? Name/position________________ / no one
3. Within the past month, have you had repeated feelings of pain, discomfort, burning, or tingling in your shoulders?
- Right shoulder (0)none________________________(10)unbearable Left shoulder (0)none________________________(10)unbearable
- If a date and place of injury is known, please describe in the margin next to the body part marked above. To whom did you report the injury? Name/position______________ / no one
4. Have any of the above symptoms caused you to be awakened while sleeping? Yes No
5. Within the past month have you experienced low back pain?
- Low back (0)none________________________(10)unbearable Mid back (0)none________________________(10)unbearable Upper back (0)none________________________(10)unbearable Neck (0)none________________________(10)unbearable
- If a date and place of injury is known, please describe in the margin next to the body part marked above. To whom did you report the injury? Name/position________________ / no one
6. What time does your discomfort occur regularly? Time Discomfort Describe Mornings? Yes No Afternoons? Yes No Evenings? Yes No Night? Yes No
7. Does your discomfort listed above interfere with your daily activities (eating, writing, driving, sports, etc.)?
8. Have you ever received medical treatment for this pain and discomfort? Please note "listed above" if already noted.
- Treatment Date ________________________________________________________
9. Has a medical professional ever given you a diagnosis of:
- Carpal tunnel syndrome? Yes No Job related? Y N Ganglionic cysts? Yes No Job related? Y N Cubital tunnel syndrome Yes No Job related? Y N Tendinitis? Yes No Job related? Y N Tenosynovitis? Yes No Job related? Y N Bursitis? Yes No Job related? Y N Epicondylitis? Yes No Job related? Y N Cervical strain? Yes No Job related? Y N Groin strain? Yes No Job related? Y N Sciatica? Yes No Job related? Y N Rotator Cuff Syndrome? Yes No Job related? Y N Knee Injury? Yes No Job related? Y N Disc Injury? Yes No Job related? Y N Fractured vertebra(e)? Yes No Job related? Y N Spondylosis? Yes No Job related? Y N Back strain? Yes No Job related? Y N Other?__________________________ Job related? Y N __________________________ Job related? Y N
- NOTE: This list is not exhaustive. Other health outcomes exist and may be related to a job.
10. Have you ever had surgery for any of these conditions? Please note the date of surgery by the appropriate medical condition listed above.
11. Does your present job require heavy lifting, pushing, pulling, carrying and/or lowering? Y N Explain: __________________________________________________
On the picture below, please mark the areas where you have experienced repeated pain within the last month. Place an "N" for numbness, "P" for pain, "T" for tingling, "S" for soreness, "D" for discomfort and/or "F" for fatigue.
The questions below refer to psychosocial aspects of the employee's work. Please answer the questions below as accurately as possible.
S= Sometimes O= Often N= Never
12. Do you learn new things on your job? S O N 13. Does your job require a lot of skill? S O N 14. Are you free to make a decision on your job? S O N 15. Do you have a lot to say about how to do your job? S O N 16. Do you have more work than you can easily handle? S O N 17. Do you get conflicting orders? S O N 18. Are you required to work fast? S O N 19. Do you work hard? S O N 20. What is the worst part about your job?______________________
- To whom reported/date?______________________________________
21. What has your employer/supervisor done to improve your job? ____________________________________________________________
- Were changes made with employees' input? _______
22. What is the best part about your job?_______________________
23. How could your job be improved?_____________________________
- Have you offered these suggestions to your supervisor?______
- Date suggestions offered____________________
23. Is it difficult for you to be honest in this survey? Y N
- Appendix B
The Peak Performance Motion Analysis System
The description of the modelling system below was provided by Thomas J. Shepich, Director of Technical Support. Examples included herein, of applications of the system, have been provided by Brian Carnahan, Ergonomist in the Office of Technical Support.
The Peak Performance Motion Analysis system generates computer graphic representation of human movement and its kinematic elements (i.e., displacement, velocity, acceleration) from video tape. The system can, if used properly, provide detailed information regarding the stresses placed on the musculoskeletal system via dynamic biomechanical modeling. Biomechanics uses the laws of physics and engineering concepts to describe motion undergone by the various body segments and the forces acting on these body segments during normal daily activities. This information gives the analyst insight into what specific changes should be made to a workstation or task methods that would reduce the ergonomic risk factors placed on the worker. With respect to dynamic manual activities, such information cannot be acquired solely through the use of the NIOSH Lift Guide. The system does, however, have limitations that must be considered if it is used in the context of performing an ergonomic evaluation.
By using the Peak Performance system, manual materials handling activities such as lifting, lowering, pushing, and pulling, can be analyzed directly from video tape. Utilizing computer programming to create the appropriate biomechanical model (a series of mathematical equations) the following ergonomic stressors can be calculated with regard to their magnitude and changes across the time required to perform the activity.
- * The compressive force placed on the spinal column of the low back (L5/S1 disc).
- * The anterior/posterior shear force placed on the spinal column of the low back (L5/S1 disc).
- * The moments (torques) placed on the elbow, shoulder, and hip joints.
- * The percentage of maximum voluntary torque generated at the elbow, shoulder, and hip joints for the below average, average, and strongest male or female workers.
- * The severity and relative duration (percentage of total task time) of back flexion, shoulder flexion/abduction, and wrist deviation.
It should be noted that several limitations must be taken into consideration when using the Peak Performance system to generate occupational biomechanical data for ergonomic analysis:
- * The calculated ergonomic stressors are estimates based on assumptions regarding weight distribution, the force on the hands, the location of joint centers, and muscle activation/orientation. The more assumptions that are required to perform a particular analysis, the greater the potential error in the accuracy of the calculations.
- * Because the system relies on two-dimensional analysis, the tasks evaluated must be symmetric (the right and left sides of the worker must be mirror images of one another). The system becomes ineffective as a tool of analysis when the subject performs asymmetric activities which are more realistic and more frequently found in occupational settings. (An example of asymmetry would be a task where a person uses one arm and not the other.)
- * To use the system properly, the CSHO must adhere to the following guidelines: (1) The camera must be stationary at all times; (2) The subject must be video taped at an angle that captures their entire upper body either in profile, a full frontal view, or a full posterior view; (3) An object of known length must be in the same field of view as the worker (In warehouse situations, a pallet may suffice since its length can be measured once and assumed the same for all other pallets); (4) A stationary point must be in the field of view all times; (5) The weight and gender of the operator must be recorded.
- Utilization of The Peak Performance Model
- * The biomechanical modeling utilized in this system is adequate for simple handling tasks such as lifting, lowering, pushing, and pulling. However, for faster and more biomechanically complex tasks such as electronic assembly work and typing), the system would prove ineffective as a tool of ergonomic analysis.
If this system is to be used in the context of enforcement, the biomechanical data generated should be considered only as a single piece of evidence supplemented and supported by the following criteria where possible:
- * Physiological Evidence - the estimated metabolic energy expenditure required on the part of the worker to perform the task. These estimates should be compared to recommended guidelines set forth by the National Institute of Occupational Safety and Health as well as the American Industrial Hygiene Association.
- * Psychophysical Evidence - the subjective estimate of the maximum weight or force the worker feels he or she can safely handle given the type of exertion, the frequency of the exertion, and the physical parameters of the job. This evaluation is accomplished by comparing the actual weights handled by the worker to data tables containing the maximum weights acceptable to industrial populations. "Acceptable" in this context, is defined as the maximum load a worker feels they can handle without straining, becoming unusually tired, weakened, overheated, or out of breath. In addition, psychophysical scales such as those provided in Appendix C may be used.
- * Epidemiological Evidence - the evidence found in the OSHA 200 and 101 forms of an employer that documents the prevalence of musculoskeletal injuries' and illnesses in the workplace and directly associates these injuries and illnesses to the task which is being evaluated. The job turn-over rate and employee interviews should be taken into consideration as well.
- * These criteria may be used to base conclusions on facts; and only then can recommendations be made on conclusions.
Application Once documentation of the hazards has been achieved, what do you do with the information? A simplified example is provided below:
Case example: FACTORY XYZ HAS 780 EMPLOYEES, 75 OF WHOM WORK IN JOB A, PICKING PRODUCTS FROM THE WAREHOUSE AND BUILDING PALLETS. STATISTICS WERE CALCULATED FOR BACK INJURIES ONLY. THE PURPOSE OF THE INSPECTION WAS TO RESPOND TO A FORMAL COMPLAIN ABOUT THE HAZARDS ASSOCIATED WITH LIFTING IN JOB A. SIXTY-FOUR OF THE 75 EMPLOYEES IN JOB A WERE INTERVIEWED AND SURVEYED FOR SYMPTOMS.
Facts Conclusions Recommendations
In 1992 IR (plant) = 3.2 Incidence rate is high Ergonomic analysis IR (industry) = 6.4 compared to plant and of job A IR (job) = 37.0 the industry IR for IR (job B) = 3.4 all injuries (BLS data) Also, workers in job A are 12 time more likely to incur a back injury than those who work in job B.
1990 IR (job A) = 25 The incident rate has Ergonomic analysis 1991 IR (job A) = 32 increased over the of job A 1992 IR (job A) = 37 last three years Medical management
Severity is 5980 lost Employees have Ergonomic analysis workdays per 100 experienced serious Medical management employees in 1992, not physical harm Education and training including workers still out of work due to injury.
Prevalence for back At the time of the Medical management pain for workers in inspection, most Education and training job A on 2/18/93 was workers in job A Ergonomic analysis .92 were in pain
Average whole body Workers work hard Consider decreasing perceived exertion is workload or rate 16 during 8 hour shift Decrease duration (see psychophysical scales) Use mechanical assists
Peak performance model Force is too high Decrease weight shows that forces used Use engineering exceeds guidelines controls Use 2 person lift
Facts Conclusions Recommendations Energy expenditure Energy expenditure Decrease number of exceeds guidelines of is too high lifts/travel dist. 5.2 Kcal per min. Increase rest breaks Use conveyors for travel Use carts far travel
Biomechanical model Force on spine Decrease weight shows compressive too high Decrease horiz. dist. force exceeds Keep load at waist safe level level
75% of lifts exceed Workers lift too Decrease freq. the MPL of the 1981 frequently Use more workers NIOSH guidelines. The Engineering controls most significant factor is the frequency of lifts
Once you have your recommendations, you can rank the preference of engineering controls using the chart below. Prior to the citation or 5(a)(1) letter, you should discuss the feasibility of controls with the employer and employees.
Examples of HAZARDS Examples of Engineering CONTROLS
- Conveyors Lift table Handles Handtruck ------------------------------------------
Frequency too high | | | ---------------------------------+------------+--------+--------- Duration of lift too long X | | | X ---------------------------------+------------+--------+--------- Too much weight X | X | | X ---------------------------------+------------+--------+--------- Twisting ? |Depends | ? | |where placed| | ---------------------------------+------------+--------+--------- Poor coupling | | X | ---------------------------------+------------+--------+--------- Horizontal distance too far X | X | | ---------------------------------+------------+--------+--------- Starting height too low | X | | ---------------------------------+------------+--------+--------- Ending height too high X | X | | ---------------------------------+------------+--------+--------- Carrying too far X | | | X ---------------------------------+------------+--------+--------- Constrained space | | | ? ---------------------------------+------------+--------+--------- Slippery floor | | | -----------------------------------------------------------------
- Psychophysical scales (sample application)
This questionnaire can be created to suit the needs of the case. The objective here is to provide an estimation for muscle force and energy expenditure on the job. Psychophysical tables have also been published with information on acceptable weights that can be lifted under certain conditions by specific, industrial populations. Please contact the Regional Ergonomist for these references as well as for information on Biomechanical, energy expenditure and work rate capacity models.
HOURS WORKED PER DAY:________
HOURS WORKED PER WEEK:_______
AGE:____ HEIGHT:__________ SEX: M F REST BREAK SCHEDULE:________________
IS EXERTION: RARE SELDOM OFTEN CONTINUOUS VARIABLE ? (circle one)
Employee: Please describe the tasks you perform on your job and the approximate time spent doing the task. Use the scales provided by the compliance officer to estimate your exertion for each task.
Example: Task: Pull trays from oven when muffins cooked Exertion: often - 60 trays / 2 hours Pull 48 muffin trays from oven Large Muscle Whole body exertion Shoulder Low back 12 6 4
- Task Whole body exertion Large muscle (6-20) group (0-10) (state which body parts work most) 1._______________________________________________________________
Ratings of Perceived Exertion Scales
- Category Scale for Rating of Perceived Exertion Large-Muscle-Group Activity Rating of Perceived Exertion Borg, 1980. Whole Body effort Borg, 1962.
19 Very, very hard 10 Very, very strong (almost
17 Very hard 8
16 7 Very strong
15 Hard 6
14 5 Strong (heavy)
13 Somewhat hard 4 Somewhat strong
12 3 Moderate
11 Fairly 2 Weak (light)
10 1 Very weak
9 Very light 0.5 Very, very weak (just
noticeable) 8 0 Nothing at all 7 Very, very light
Borg, G.A.V., 1962. Physical Performance of Perceived Exertion. Lund, Sweden: Gleerups.
Borg, G.A.V., 1980. A Category Scale with Ratio Properties for Intermodal and Interindividual Comparisons. Paper presented at the international Congress of Psychology, Leibig, West Germany, 1980.