Comparison Of Measurement And Evaluation Criteria Of Hand - Transmitted Vibration And Measurement Method

ObjectiveThe goal of this review is to put forward the advice on improving the HTV measuring and evaluation standard in China to compare the domestic and overseas measuring and evaluation standards of hand-transmitted vibration (HTV).Additional, analysis the influence factors of different the HTV measuring methods, different HTV instruments and different vibration duration in workplace.MethodsThe first, carded system the criteria and the literature for hand-transmitted vibration, and compared hand-transmitted vibration measurement and evaluation criteria,then, analyzed the situation of standard application and research;Secondly,to select a representative work tools and operations personnel in a large automobile plant production chain, studied the main contents of the standard field-proven (including accelerometers fixed and installed hand connection, each pick-up time the record, date of calculation of the amount of vibration spectrum analysis, etc.) and took investigation by unified homemade questionnaire,based on site measurement data for comparison between the relative error and the measurement time,and for prediction the total hand vibration by tree dominant axis;Finally,in grinding workplace,acquisition of data between different measurement methods, and then use SAS9.2 for statistical data analysis.ResultsFirst of all,compare the domestic and overseas measuring and evaluation standards of hand-transmitted vibration (HTV).First,compared with ISO 5349,there are main differentiation including terminology,aspects of the introduction of reference standards,specific measurement and evaluation methods,appendix,and so on.Second,American Standard ANSI2.70 combine ISO5349 and EU Physical Agents (Vibration) guidelines (2002/44/EC) in the main part of that involves the measurement and evaluation of ISO5349 main content, but also guide the prevention and control measures and health surveillance content.And the end,after review of the literature, this paper makes a review of HTV research and standard usage.lt is took a different view in the measurement time, respect the total amount of vibration calculation and evaluation methods and that should further improve the standard of some of the content.Second, According to the above study,the vibration tool’s attribute was measured and evaluated on filed.To confirm existing method of measure about location of accelerometers;attaching accelerometers;vibration time of record calculation of daily vibration exposure;1/3 octave spectrum.International Standard ISO 5349 is closer to reality, to solve practical problems in the process of measurement and evaluation.ISO 5349 also is the manual book of a reference value.The common hand vibration tool characteristics:① There are four vibration waveform,including random waveform,attack waveform,long period waveform,short period waveform;② Vibration margin:Impact Wrench is 0.3-6.17m/s2, Grinder is 1.61～7.72m/s2, the mill is 1.46-8.70m/s2, Arc welding machine is 0.21～2.18m/s2;③ Maximum margin of 1/3 octave frequency spectrum:Electric(Impact) Wrench is 100Hz, Plasma cutting machine is 0.8Hz,Shearing machine is 80Hz,Grinder is 800Hz, the mill (grinder)is 500Hz, the mill (titanium alloy)is 500Hz,Arc welding machine is 0.4-2.5Hz,Drills shock is 400Hz;④Following 50Hz-800Hz in Grinder, the mill.angle grinder have already exceeded recommendations of vibration limit;⑤ Daily vibration exposure:Polished position (A(4)3.76～8.03m/s2,A(8)5.36-10.39m/s2)had already exceeded national vibration limrt(A(4)5.0m/s2 or A(8)3.5m/s2).Investigation by unified homemade questionnaire:①Operation posture:standing(63.3%), sitting(30%), squatting;② Operation mode:right hand (35%), left hand, double hand(65%);③ Intermittent operation:in grinder is10min(80%),10(20min(15%);in wrench is always 20min;④Age of working:<5 years(80%),6(10years(13.3%),>10years(6.7%);⑤The cumulative amount of vibration:average the cumulative amount of vibration is 10270.7hours,the maximum of the male is 36040h,the maximum of the female is 58300h.The investigation is shown that workers mainly abnormal sense of hand about numbness(68%), hand pain(65%), hand swelling(45%).Finally,the different method of compared:①To analyze differentiation of four locations of acceleration adaption:The coefficient of variation are " U "<"O"<"一" <"T"<"S ".With respect to the mean, the smaller the degree of variation, the stronger the stability of the data.Significant group differences were found in different location of acceleration (all P<0.0001).Comparison of two groups,There were no statistically significant group differences in "O" and "一 " group (P=0.603>0.05; P=0.0967>0.05),but two of another groups were significant group differences(all p<0.0001);②To explore measurement consistency from AWA instruction of vibration system with "U" locations of acceleration adaption and SVAN instruction of vibration system:ICC=0.818,another location ICC is under 0.4;③To compare relative error with time of measurement result in workplace:following 8s sampling methods and 80%accuracy,the hand-arm vibration tool with random waveform and attack waveform of relative error is 2～9;the period waveform tool of relative error is about 4; ④To predict the total hand vibration by tree dominant axis,the regression equations were:aa=0.623+1.028xx,aa=0.576+0.937xx,aa=0.629+0.917xx;The propertions of tree dominant axis and total accelerometer value among the X axis、Y axis、Z axis were0.991～1.068、0.910～0.963、0.896-0.939,and the correlation coefficients are 0.954,0.971,0.981 (P<0.0001).The multiplication factor calculated is 1.7 for the measured axis represents the vibration in all three axes,that is as same as the list of 6.1.6 in ISO 5349-2.ConclusionsTo development our hand-transmitted standards, we had better to study a series of vibration standards which had already established at home and abroad; Before the introduction of international standards, it is necessary to confirm the content of standards in China’s actual workplace.Through on-field measurement and measurement data within multiple groups, mastered the common oscillating hand tool of vibration characteristics and the general condition of the hand-transmitted vibration,confirmed the practicality of ISO 5349 measurement methods.Proposed suggested improvements to hand-transmitted vibration measurement and evaluation criteria:①Both hands to operate is popular in HTV workplace. It is necessary to measureboth hands of operation.Using of different working tools in operation period should be considered.According the different vibration mode respectively defined daily time record.②affected by the environment and the operator and many other factors, should be appropriately increased the number of measurements, record the mean, standard deviation and coefficient of variation.For suddenly higher than other value measurements, in the absence of reliable evidence that is caused by gross error, it should not be deleted;③Acceleration adapter placement has a great influence on the results; Adapter shall be mounted perpendicularly to the grinder surface of the handle where operator normally places his hand.Further research is still needed that the exact location of adapter in the hands.④The measurement data of "U" shape adapter to join AWA instrument in the handle of grinder ensured reliability and comparability with fan palms adapter to join SVAN instrument in hands of operator.⑤Following 8s sampling methods and 80%accuracy,the hand-arm vibration tool with random waveform and attack waveform of relative error is 29;the period waveform tool of relative error is about 4.1f tool of relative error is 4,the recommended sampling methods time of random waveform is 40s,to attack waveform is more than 15s.The measurement time is extended to 40 seconds or 60 seconds is appropriate, still need more data to demonstrate.⑥For 8 hours of a fixed amount of vibration trades daily pick-up time is more suitable by the daily vibration exposure A(8);For the daily reality of vibration of less 4 hours, calculated using the four hours it is more appropriate.⑦Spectrum analysis can directly reflect the operation process tool vibration,so it can be used as an auxiliary method of evaluation.⑧It can be inferred by a mathematical model to predict the total hand vibration with tree dominant axis,multiplied factor is 1.7 that is in line with recommendation of ISO 5349.To use dominant axis vibration prediction method still needs further study.Most occupational disease prevention agency is not in place to hand-transmitted vibration workplace regulation.The limit of HTV can not completely control the occurrence of hand-arm vibration syndrome and China is still a lack of hands transmitted vibration protection guidelines for a variety of workplace hazards occupation,so investigation and research on HTV should be strengthened.It is necessary to speed up the research process for each standard, in order to adapt social development.