ABSTRACT
Background Hand-arm vibration disease is harmful to human body, but there are no effective diagnosis and treatment so far, and current occupational exposure limits underestimate the health damage caused by high-frequency vibration exposure. Objective To evaluate and compare the damage to workers' peripheral circulation and peripheral nerve caused by different frequencies of vibration operation. Methods Drilling workers (n=187) from a mining company in Shandong Province and golf club head grinding workers (n=228) from a sports equipment factory in Guangdong Province were selected as study subjects. Hand symptoms were investigated. SV106 vibration meter was used to measure the target operation-associated vibration frequency spectrum. The 8 h energy-equivalent frequency weighted acceleration, cumulative vibration exposure level (CVEL), and the working age related to causing white finger in 10% of an exposed group were calculated. Result The study subjects were all male. More grinding workers reported hand symptoms than the drilling workers, e.g. peripheral circulation injury (52.6% vs 19.3%), peripheral nerve injury (71.5% vs 23.0%), hand stiffness (64.0% vs 7.0%), and deformed fingers (69.7% vs 4.3%) (all P<0.001). The main vibration frequencies of grinding operation (500-800 Hz) were much higher than those of drilling operation (125~160 Hz). CVEL and working age of vibration exposure showed a linear rising relationship with the cumulative prevalence rate of peripheral circulation and peripheral never injury, the fitting lines all showed good fitting effects (R2=0.812-0.988), and the slope of the fitting line of the grinding workers was larger than that of the drilling workers. The working age of vibration exposure associated with 10% cumulative prevalence of white finger was shorter in the grinding workers than in the drilling workers (6.81 years vs 10.27 years). According to the ISO prediction formula, the working age of vibration exposure was associated with 10% white finger prevalence shorter in the drilling workers than in the grinding workers (3.12 years vs 8.23 years). Conclusion Both the vibration exposure level and the prevalence of hand symptoms are high in two groups of workers with different vibration frequencies, and vibration exposure at a higher frequency tends to have severer damage to workers' hands.
ABSTRACT
Se estudió el aislamiento a la vibración, por medio del factor SEAT (Seat Effective Amplitude Transmissibility), de 4 tipos de asientos de grúa de horquilla, los cuales se seleccionaron por poseer distintos sistemas de amortiguamiento a las vibraciones. Los asiento utilizados fueron los modelos GRAMMER MSG71GBLV (SEAT = 0,55 en el eje Z), KAB Seating 21/T1 (SEAT = 0,96 en el eje Z), GENÉRICO BF2-3 (SEAT = 1,01 en el eje Z) y GENÉRICO BFL-3 (SEAT = 0,82 en el eje Z). Para obtener los valores SEAT, se efectuaron mediciones de 30 minutos para 2 condiciones, desplazamiento del vehículo sin carga durante 20 minutos por una ruta de 6 kilómetros y, luego, simulando una condición de trabajo habitual de una grúa de horquilla para trabajo cíclico con carga por un período de tiempo aproximado de 10 minutos. Adicionalmente, se evaluó la exposición a vibración del operador de la grúa de horquilla seleccionada según el D.S. N° 594/1999 y Directiva 2002/44/CE, documentos basados en la norma ISO 2631-1, con el fin de estudiar el efecto de los asientos en la exposición del operador y el nivel de riesgo asociado, para entregar recomendaciones sobre la selección y uso de asientos en grúas de horquilla.
It was studied the isolation of vibration by means of factor SEAT (Seat Effective Amplitude transmissibility) on 4 types of seat forklift truck, which were selected for having different systems of vibration damping. The seat models used were GRAMMER MSG71GBLV (SEAT = 0.55 in the Z axis), KAB Seating 21/T1 (SEAT = 0.96 in the Z axis), Generic BFL-3 (SEAT = 1.01 in the axis Z) and generic BFL-3 (SEAT = 0.82 in the Z axis). To obtain SEAT values, it were performed measurements of 30 minutes for 2 conditions, moving vehicle without load for 20 minutes by a 6 kilometer route and, then, simulating a typical work of a forklift truck to cyclic work with load for a period of time of approximately 10 minutes. Additionally, the exposure to vibration of selected forklift truck operator was evaluated according to the DS N ° 594/1999 and Directive 2002/44/EC documents based on ISO 2631-1, in order to study the effect of the seats in operator exposure and the level of associated risk, to provide recommendations on selection and use of forklift trucks seats.
Subject(s)
Humans , Vibration , Occupational Exposure/analysis , Motor VehiclesABSTRACT
BACKGROUND: Cassava and corn milling is a growing small-scale enterprise in Africa. We aimed to determine the incidence of hand-arm musculoskeletal complaints among vibration-exposed Congolese cassava and corn millers in the previous 12 months. METHODS: A cross-sectional study was conducted, prior to a follow-up study, from March to May 2013 among cassava/corn millers in Lubumbashi, Democratic Republic of Congo, in which 365 millers age-matched to 365 civil workers anonymously answered a questionnaire. RESULTS: Overall incidence of hand-arm musculoskeletal complaints was 25.8% in millers (vs. 5.2% in civil workers; p 8 hours; vs. those working < or = 8 hours; OR = 3.56; 95% CI: 1.93-3.61; p = 0.026); and 7.4 times higher in young millers (vs. older millers, OR = 7.39; 95% CI: 1.29-75.52; p < 0.001). Smoking, number of cigarettes, and daily exposure duration were positively correlated with musculoskeletal complaints. CONCLUSION: This study revealed a relatively high incidence of musculoskeletal complaints among African cassava and corn millers. The use of anti-vibration protective equipment and the regulation of this hazardous occupation may reduce the burden of musculoskeletal disorders in millers.