Occupational Ergonomics - Volume 6, issue 3-4

Authors: Eger, Tammy | Salmoni, Alan | Cann, Adam | Jack, Robert

Article Type: Research Article

Abstract: Whole-body vibration exposure levels were measured during the operation of fifteen different types of mobile mining equipment commonly used in Ontario mines. A tri-axial seat pad accelerometer was used to measure vibration exposure when the mining vehicle was operated from a seated position and a tri-axial accelerometer secured to floor, between the operator's feet, was used to measure vibration exposure when the mining equipment was operated from a standing position. Measurements were conducted in accordance with the procedures described in the 1997 ISO 2631-1 standard. Determination of likely health risks for equipment operators were based on a comparison of the …measured vibration exposure levels with Health Guidance Caution Zone limits presented in Annex B of the ISO 2631-1 standard. Six vehicles (UG haulage truck, bulldozer, 3.5 yard LHD, cavo loader, muck machine, and personnel carrying tractor) were above the Health Guidance Caution Zone limit, assuming an eight hour exposure period while four vehicles (grader, 7 yard LHD, scissor lift truck and locomotive) were within the Health Guidance Caution Zone limit. Show more

Keywords: Whole-body vibration, mining equipment, seated vibration exposure, standing vibration exposure, ISO 2631-1 standard

DOI: 10.3233/OER-2006-63-401

Citation: Occupational Ergonomics, vol. 6, no. 3-4, pp. 121-127, 2006

Authors: Uppu, Nageswara Rao | Aghazadeh, Fereydoun | Nabatilan, Larry

Article Type: Research Article

Abstract: This study was conducted to investigate the effect of wearing a VKK-6M pressure suit on functional reach limitations. Participants' reach data were collected with and without-suit and analyzed to see the effect of pressure suit on reach. The study concludes that wearing pressure suit reduces the average reach significantly by 3.57 cm. The 5th percentile Asian and American reach envelopes are derived for placement of critical cockpit controls. Population-reach study shows a significant difference in shoulder breadth of Americans and Asians, but no apparent relationship between bideltoid breadth and thumb tip reach is found.

Keywords: Maximum reach envelope, workplace design, engineering anthropometry, pressure suit

DOI: 10.3233/OER-2006-63-402

Citation: Occupational Ergonomics, vol. 6, no. 3-4, pp. 129-142, 2006

Authors: Chattopadhyay, Subhra | Mukherjee, Sandip | Syamal, Alak K. | Sen, Devashish | Mitra, Chandan

Article Type: Research Article

Abstract: The purpose of this study was to examine posture-comfort-performance interrelationships in plucking-based task in a tea garden. Results of coefficient of correlation between the stature bush height ratio (SBHr) and total yield (TY) (permanent: r=0.80, temporary: r=0.81), and SBHr and body part discomfort frequency and severity (BPDFS) (permanent: r=−0.78, temporary: r=−0.77) clearly indicated that performance (TY) was correlated both with the SBHr and BPDFS. Similar correlation studies between duration (TT) and BPDFS revealed that BPDFS increased with progression of time. Analysis of joint angle changes (trunk angle 92%, shoulder angle 63% and neck angle 87%) further suggests that both BPDFS …and overall postural shifts (in terms of changes in joint angles) increased with the progression of time (time on task – TT). Body part discomfort (BPD) rank order of different body parts of pluckers (upper body part discomfort scores – permanent: 2.00–6.00, temporary: 1.88–5.88; lower body part discomfort scores – permanent: 2.13–2.88, temporary: 1.88–2.75) further revealed that upper body parts were mostly involved in discomfort development. These results suggest that an overall postural shift may be a good indicator of perceived musculoskeletal discomfort in a tea leaf plucking task where a constrained posture is required. Results of independent test series suggest that there was a good agreement between the predicted and observed values of the different variables (89.6–96.3%). The predictive value of the regression equations may be utilized for estimating values of different interacting variables, and thus, the importance of these regression equations in the supervision of workers engaged in tea plucking is evident. It is therefore proposed that to improve performance, these observations can conveniently be utilized while plucking sectors are allotted to pluckers in a tea garden. Show more

Keywords: Tea plucking tasks, posture, performance

DOI: 10.3233/OER-2006-63-403

Citation: Occupational Ergonomics, vol. 6, no. 3-4, pp. 143-157, 2006

Authors: Landau, Kurt | Wiese, Gero | Bopp, Verena | Sinn-Behrendt, Andrea | Winter, Gabriele | Salmanzadeh, Hamed

Article Type: Research Article

Abstract: Because workers operating machines under mass production conditions frequently have extremely narrow, highly repetitive job contents which result in unilateral strains, a company manufacturing goods for the consumer industry sought to achieve job enrichment in this type of activity by introducing three different inspection tasks to supplement machine operation. A study of 12 workplaces using the Key Features Method, plus the IAD-BKA, OCRA- and RULA procedures and an energy expenditure calculation demonstrated the stress-reducing effect of the job enrichment concept. The EMG analyses performed on four selected muscles over a total of 12 full-shift working days also support the assumption …that changes in types of stress will be beneficial. In contrast, the before/after-shift results obtained with the Nitsch Self-rating Scale and the NASA Task Load Index indicated increases in perceived strains and decline in motivation in all subjects – despite the job enrichment action. For this reason further ergonomic job redesign action is proposed. Show more

Keywords: Job enrichment, study of stresses and strains, machine operation, quality control

DOI: 10.3233/OER-2006-63-404

Citation: Occupational Ergonomics, vol. 6, no. 3-4, pp. 159-172, 2006

Authors: Azar, Nadia R. | Andrews, David M. | Callaghan, Jack P.

Article Type: Research Article

Abstract: The purpose of this study was to predict 3D cumulative L4/L5 spine loads and moments incurred during non-occupational tasks, from heart rate determined physical activity level (HR-PAL). Twelve subjects were videotaped while performing activities in their own homes. HR was continuously recorded during video collection and was subsequently used to calculate the PAL over the course of the 2-hour collection session. Simple regression revealed that between 76% and 82% of the variance in 3 of the 13 cumulative load measures studied (cumulative compression force and cumulative flexion and right axial twist moments) was accounted for by HR-PAL. Four additional cumulative …output variables approached statistical significance. Cumulative compression force was the best predicted of all measures studied. Predicted and actual loads were not different from each other for all significant load measures. This initial study suggests that the use of heart rate for predicting cumulative compression shows potential as a simple method to track extended periods of cumulative exposure. Future work is planned to test this method in a number of industrial settings. Show more

Keywords: Heart rate, physical activity, cumulative loads, non-occupational tasks, low back

DOI: 10.3233/OER-2006-63-405

Citation: Occupational Ergonomics, vol. 6, no. 3-4, pp. 173-186, 2006

Article Type: Book Review

DOI: 10.3233/OER-2006-63-406

Citation: Occupational Ergonomics, vol. 6, no. 3-4, pp. 187-188, 2006