Vibration Total Value Research Articles

Abrupt changing aerodynamic loads resulting in diminished ride comfort when two high-speed trains intersect in a tunnel

The lateral force exerted when two trains pass each other can adversely affect train safety, and this adverse effect becomes more pronounced as the train speed increases. When trains cross paths in tunnels, the aerodynamics differ from those in open lines due to the restrictive nature of tunnel walls. Utilizing the Renormalization Group (RNG) k-ε turbulence model and the “Mosaic” grid method, this research examines changes in aerodynamic load of the train and ride comfort during a intersection at 400 km/h in a tunnel and contrasts this with conditions at 350 km/h. The results indicate that the change in aerodynamic load on each carriage is more pronounced when the head train of the oncoming train passes than when its tail train passes, with the largest variation observed during the passing of both the head and tail trains. This alteration in aerodynamic load is primarily attributed to the air being pushed in the locomotive area and the negative pressure from the vortex structure between trains. When the speed is increased from 350 km/h to 400 km/h, the aerodynamic load on the train increases by approximately 20 % to 40 %, and the acceleration of the head train grows by 20 % to 50 %. The most noticeable decrease in ride comfort is observed in the head train, with the highest increase in the head train’s Overall Vibration Total Value (OVTV), which rises by 30.1 %.

Evaluation of hand-arm vibration (HAV) exposure among groundskeepers in the southeastern United States.

The objectives of this study were to evaluate daily hand-arm vibration (HAV) exposure among groundskeepers, characterize power tools used, and estimate lifetime cumulative HAV exposure dose. Seventeen groundskeepers and ten office workers employed at two US southeasterrn institutions were recruited as a target exposure group and a reference group, respectively. A 6-d exposure assessment of HAV was scheduled, and vibration dosimeters were used to obtain daily vibration exposure value, A(8). Information on power tools used and corresponding operation duration was recorded to assign the real-time vibration data collected from the dosimeters for tool characterization in terms of vibration total value (ahv) and frequency. Lifetime cumulative exposure dose, ahv-lifetime, was determined using ahv for all tools used and lifetime exposure duration obtained through a questionnaire. The individual groundskeepers' average A(8) ranged from 0.8 to 2.6 and from 1.0 to 2.6 m/s2 for the right hand and left hands, respectively. Among 11 power tools used by the groundskeepers, grass trimmers contributed the most to the vibration exposure. The average ahv of the individual tools ranged from 8.0 (chainsaws) to 1.9 m/s2 (seating mowers and handheld blowers) for the right hand and from 6.4 (push mowers) to 1.4 m/s2 (backpack blowers) for the left hand. The highest acceleration peak of grass trimmers, edgers, backpack blowers, pole saws, riding blowers, and hedgers was observed between 100 and 200 Hz while riding mowers, seating mowers, push mowers, and chainsaws showed the highest acceleration peak at lower frequencies (≤63.5 Hz). The groundskeepers' average ahv-lifetime was 76,520.6 and 61,955.5 h m/s2 for the right and left hands, respectively. The average ahv-lifetime of office workers was 2,306.2 and 2,205.8 h m/s2 for the right and left hands, respectively, which was attributed to personal hobby activities. Three groundskeepers' average A(8) reached 2.5 m/s2, the Action Limit recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). The highest contribution to the vibration exposure was observed during grass trimmer operations with a major acceleration peak at 100 Hz. The groundskeepers' ahv-lifetime was 33 and 28 times higher for the right and left hands, respectively, than the office workers.

Ride comfort assessment of road vehicles on a long-span truss girder suspension bridge under crosswinds

The precise identification of the aerodynamic loads on vehicles is a fundamental concern in assessing the ride comfort of vehicles crossing long-span bridges in the presence of strong crosswinds. However, the consideration of aerodynamic interference between vehicles and truss girder bridges is limited in existing studies. Furthermore, in practical engineering, wind barriers are commonly installed to enhance the ride comfort of vehicles crossing long-span bridges, but previous studies have primarily focused on the impact of wind barriers on the aerodynamic coefficients and dynamic responses of vehicles. This paper focuses on the aerodynamic interaction between trucks and truss girder bridges, through wind tunnel testing. The aerodynamic coefficients of the vehicle with three different ventilation ratios and four different heights of wind barriers were obtained. The dynamic response of road vehicles on a truss girder suspension bridge with a main span of 965 m was numerically calculated using the coupled analysis of wind-vehicle-bridge system and measured aerodynamic coefficients considering aerodynamic interference. On this basis, the comfort of road vehicles was investigated with different section types of the girder and different wind barrier parameters, and it was evaluated accordance with the overall vibration total value (OVTV) recommended in the ISO 2631–1. It is found that the aerodynamic coefficients of road vehicles are sensitive to the type of wind barrier. Wind barriers can reduce the road vehicle’s aerodynamic loads at high wind yaw angles. Wind barriers can also improve the ride comfort of road vehicles on the long-span truss girder suspension bridge.

Exposure–response relationship between work-related hand–arm vibration exposure and musculoskeletal disorders of the upper extremities: the German hand–arm vibration study

ABSTRACT Objective. To quantify the exposure–response relationship between hand–arm vibration exposure and the risk of musculoskeletal disorders of the upper extremities (UMSDs), a case–control study was carried out among workers in the construction, mining, metal and woodworking industries. Methods. In total, 209 male cases and 614 controls were recruited. Cases were newly reported patients with UMSDs. Controls were a random sample of persons with compensable occupational injuries. Standardized personal interviews were performed among cases and controls by well-trained safety engineers. In addition to leisure activities and comorbidities, work histories of all participants were collected in detail. To quantify hand–arm vibration exposures, a database of vibration measurements of over 700 power tools was used. This database allows the detailed quantification of vibration exposures over time. A dose–response relationship between hand–arm vibration exposure and UMSDs was quantified by conditional logistic regression analyses. Results and conclusions. After adjusting for relevant confounders, statistically significant exposure–response relationships between cumulative hand–arm vibration exposure and UMSDs were established. A cumulative hand–arm vibration exposure of D hv (vibration total value in three measuring directions) = 142,300 (95% confidence interval [CI] [90,600–333,200]) m2/s4·day or D hw (vibration value in the direction along the forearm) = 38,700 (95% CI [25,400–80,900]) m2/s4·day is associated with a doubled risk of UMSDs.

Evaluation of Ride Comfort under Vortex-Induced Vibration of Long-Span Bridge

The increasing number of suspension bridges has led to designs favoring greater length and flexibility, resulting in a common problem of vortex-induced vibration. While vortex-induced vibration typically does not cause structural damage, it diminishes the bridge’s fatigue resistance and has a detrimental impact on ride comfort. Additionally, this study introduces a road–bridge–vehicle vibration model, proposing an evaluation method for assessing ride comfort during vortex-induced vibrations in long-span bridges. This method features simplified modeling and swift calculations, circumventing the need for intricate finite element modeling and iterative solving. Furthermore, it evaluates ride comfort for vehicles crossing a prototype long-span suspension bridge using the Overall Vibration Total Value (OVTV) and Motion Sickness Incidence (MSI) criteria. This study also analyzes the influence of various parameters on OVTV and MSI, including vehicle speed, road grade, vortex-induced vibration frequency, and amplitude. It establishes a reference limit for vortex-induced vibration amplitude based on OVTV and MSI values. Moreover, the study substantiates that, within the context of vortex-induced vibration, the MSI value is more suitable for evaluating driving comfort compared to the OVTV.

The effect of wood species on chainsaw vibrations during bucking operations

ABSTRACT This paper investigates the role of wood species on the levels and characteristics of vibrations transmitted to a chainsaw operator. Three different wood species were chosen from the forests located in the Northern part of Iran, and a “no-cutting” regime was also used as a control treatment to test the sole influence of cutting on the induced vibrations. After collecting the vibration data, the frequency-unweighted and frequency-weighted accelerations of different tests were calculated and compared to find the influential factors in determining the vibration characteristics. The effect of wood species on the vibration acceleration was found to be significant, while no significant influence of this factor on the vibration total value was detected. Instead, the cutting process amplified the vibration total value due to an increase in the vibration acceleration at lower frequencies. The results of this study showed the influence of the cutting process on the levels and characteristics of the vibrations induced by a chainsaw.

Acute physiological and functional effects of repetitive shocks on the hand–arm system: a pilot study on healthy subjects

Objectives. Exposure to hand-transmitted shocks is a widespread phenomenon in the workplace. Separate risk assessments for shocks do not exist in current international hand–arm vibration regulations, leading to potential underestimation of associated health risks. Methods. In a pilot study approach, eight healthy males were exposed to sets of 3 × 5 min of repetitive shocks and 1 × 5 min of random vibration, controlled at a weighted vibration total value of 10 m/s2. Baseline and post-exposure measurements of vibration perception thresholds, finger skin temperature, maximal grip/pinch force and the Purdue pegboard test were conducted. Muscle activity was monitored continuously by surface electromyography. Results. Shock exposures evoked a temporary increase of vibration perception thresholds with high examination frequencies. A decrease of skin temperature was hinted for shocks of 1 and 20 s–1. Electromyographical findings indicated an additional load on two forearm muscles during shock transmission. Maximum grip force and manual dexterity were not affected, and pinch force only partially reduced after the exposures. Conclusion. Physiological effects from shock exposure conform to those described for hand–arm vibration exposure in principle, although some divergence can be hypothesized. Randomized designs are required to conclusively assess the need of occupational health concepts specifically for hand-transmitted shocks.

Investigating the Relationship between Coupling Forces and Hand-Transmitted Vibration under Varying Excitation Levels

In this study, the vibration total value of the acceleration transmitted to the wrist and elbow was measured in the laboratory with a group of 13 male subjects holding a cylindrical handle while modifying the coupling force under varying levels of vibration. The results were used to establish the relationship between hand-transmitted vibration and coupling forces and to compare with the relations proposed as part of an ISO Technical Specification, ISO/TS 15230-2. This was done to determine the suitability of the proposed relationships when variations are introduced on the level of vibration on the handle. While tracing back the origins of the relations proposed in ISO/TS 15230-2, this paper further brings in evidence of the importance of considering the role of coupling forces when evaluating the exposure to hand-transmitted vibration and provides additional evidence to support the relationships which are proposed as part of the ISO Technical Specification. Irrespective of the level of broadband random vibration excitation considered, the agreement with these relationships was found to be best when setting the reference coupling force at 50, 75, 100 and 125 N and whenever the coupling forces applied on the handle were maintained below 150 N.

Ride comfort evaluation of stochastic traffic flow crossing long-span suspension bridge experiencing vortex-induced vibration

The long-span bridge is susceptible to various wind-induced vibrations owing to its high flexibility and low structural damping, among which the vortex-induced vibration (VIV) frequently emerges in recent years resulting in considerable public concerns. Although the VIV is a limited cyclic vibration, it can cause significant negative effects on the ride comfort of vehicles crossing the bridge. Evaluating the ride comfort of vehicles crossing long-span bridges under VIV, therefore, becomes urgent to make decisions on continuing or closing the operations of bridges. In view of this, this paper presents a general ride comfort evaluation procedure for stochastic traffic flow crossing the long-span bridge under VIV, which adequately considers the realistic traffic behavior and the complex interactions among wind, vehicles (traffic flow), and bridge. The developed procedure is validated through the field-monitoring data collected in a recent VIV event of a prototype long-span suspension bridge. On this basis, the ride comfort of vehicles in different traffic flows crossing the prototype bridge under VIV is evaluated through the criteria recommended in the ISO 2631-1 standard based on the overall vibration total value (OVTV). Moreover, the effects of traffic density, traffic proportion, and road roughness on drivers’ ride comfort are studied.

Study on reduction of hand-transmitted vibration in self propelled vertical conveyor reaper by isolators

The self propelled vertical conveyor reaper is commonly used for harvesting wheat, rice etc. It has become a main or the sole of mechanical power source on small and medium size farms in India. The operators of VCR are exposed to a high level of vibration arising from single cylinder engine during field operations. The vibration from the VCR is transmitted from handle to hands, arms and shoulders. In the present study, experiments were conducted to reduce the vibration extent in VCR for two operational conditions i.e. transportation on bitumen road and wheat harvesting operation by using isolators in between engine and chassis. The vibrations were measured at engine speed 2200 and 2800 rpm. In this study it was found that the vibration magnitudes decreased with increase in engine speed from 2200 to 2800 rpm in both operational conditions. The highest vibration values were observed in x-direction. The maximum frequency-weighted vibration acceleration (rms) in x-direction was 18.76 and 22.8 ms-2 in transportation and wheat harvesting, respectively. After incorporation of isolators the vibration total values reduced at 2200 rpm form 22.8 ms-2 to 9.63 ms-2 and 28.11 ms-2 to 12.57 ms-2 in transportation and wheat harvesting, respectively (Fig. 1 and 2). Whereas at 2800 rpm the vibration total values reduced form 12.93 ms-2 to 5.85ms-2 and 17.86 ms-2 to 8.42 ms-2, respectively. The average increment in 8 hour exposure time for occurrence of white finger syndrome from 1.16 to 2.88 year and 0.93 to 2.17 year for isolators in transportation and wheat harvesting, respectively.

An enhanced whole-body vibration emission index for railway vehicles

Whole-body vibration (WBV) is a concept that is gaining importance in the railway sector. Occupational disorders, such as back pain and sciatica, frequently cause sick leave and have resulted in lawsuits against employers. Railway operators require a clear procedure for specification and purchase of certified rail vehicles that evaluate the vehicle from the point of view of the effect of WBV. However, a review of current standards and studies shows no clear and simple method for defining a vibration emission value, such as that defined in EN 1032 for mobile machinery. This study proposes a systematic and robust railway driver-related vibration index and describes the methodology for its determination. The proposed index, based on current WBV standards, is robust and allows comparisons between vehicles. For index validation, we used experimental results as well as results from a neural network using the cabin floor data. Practitioner summary: A new vibration emission index is proposed for the certification of railway vehicles, using whole-body vibration, based on current standards. It could be used as a criterion when purchasing a vehicle and as a design specification for manufacturers, thereby improving the ergonomics of drivers’ working environment. Abbreviations: EAV: exposure action value; RMS: root mean square; VDV: vibration dose value; VEI: vibration emission index; VTV: vibration total value; WBV: whole-body vibration

Scottish cycling pavement assessment using hand–arm vibration exposure

A defective pavement surface discourages cyclists from selecting certain routes, and vibration exposure is a noticeable consequence of reduced path surface quality. Current asset management practice includes walkover surveys and cyclists reporting defects directly to the local authority. This research proposes the use of an instrumented probe bicycle to collect data for the assessment of pavement condition and rider comfort. Furthermore, the collection of hand–arm vibration exposure data is proposed as a means of assessing pavement surface condition and suitability. Hand–arm vibration exposure has been measured in compliance with BS EN ISO 5349-1:2001. Root-mean-square vibration total values, vibration dose value and exposure values (15, 30 and 60 min) are provided for 13·682 km of pavement surface in Edinburgh, Scotland. The vibration exposure values are compared to those recommended by EU Directive 2002/44/EC. Power spectral analysis is also performed to determine the power transferred to the cyclist’s hands and arms. The collated vibration data may be used as a means of assessing pavement surface condition. Such data may prove beneficial for local authority asset management associated with resurfacing or repair works.

Passsenger Ride Comfort and International Roughness Index Specifications in the Slovak Republic

New original results are presented on relation between passenger’s whole-body vibration (WBV) and longitudinal road unevenness characterised by the International Roughness Index (IRI) in 100-m segments. Measurements were provided in nine different cars of six vehicle categories operated on about 1860 km of road network. Vibration total value based on the root mean square (RMS) of the frequency-weighted acceleration was used to quantify the ride comfort at seat surface and seat base (i.e. vehicle floor) in three orthogonal axes. The relations between passenger’s acceleration response, comfort reaction levels according to the ISO 2631-1: 1997 and the IRI road unevenness classes, used by the Slovak Road Administration, were estimated. Results indicated higher WBV by ~ 20 % on the motorways than on the 1st and 2nd class roads in the same IRI road class. Using the same IRI road classes for motorways and the 1st and 2nd class roads seems not to be appropriate from the point of view of the whole-body vibrations.

Vibration on the backs of mistblower operators: is it only a (dis)comfort question?

Mistblowers, also called powered backpack or knapsack sprayers, are found in many countries. Because of their low cost, adaptability and easy to use, they are often used in small-scale farms and in sloping fields. They are usually powered by an internal combustion engine which produces vibrations that are transmitted to the operator's body (hands, back, shoulders). In this work the vibration produced on the backs of twenty operators operating three mistblowers were studied in field, with the tank filled with 1, 5 and 10 l of pesticide with low and high engine speeds. The former occurs when the operator moves in field, the latter during the spraying. The vibration behaviour of the mistblowers was also tested in laboratory. There are no suitable standards to determine the risk of the vibration exposure to the operator's back using backpack machines. The standard ISO 2631-1:1997 allows only a discomfort condition to be estimated. In our tests the highest Comfort Vibration Total Values (CVTV) were observed in field with the tank filled with 1 l of pesticide and at low engine speed. There were no statistically significant differences in the CVTVs among the operators, and one of the three machines (the oldest with a low level of maintenance) produced the highest CVTVs; up to 0.62 m s−2. The x-axis (fore-and-aft direction) was the most dominant. The dominant one-third octave band centre frequency (or mid-frequency, ISO 5349-1: 2001) was 40 for the low engine speed and 100 Hz for the high engine speed.

Evaluation and analysis of occupational ride comfort in rotary soil tillage operation

The present study investigates the effect of tractor ride conditions like forward speed, pulling force and tillage depth on overall vibration total value (OVTV). Taguchi’s L27 orthogonal array was used to conduct experiments on post-harvested paddy field. Response Surface Methodology (RSM) was utilized to obtain linear and quadratic predictive models that can be used to optimize the ride conditions for minimizing OVTV. The magnitude of overall vibration total value varies from 0.727 to 0.913 m/s2 among all the experiments. Analysis of variance (ANOVA) shows that forward speed and pulling force are significant at 5% level. The percentage contribution of forward speed, pulling force, and tillage depth is found to be 76.249%, 21.174%, and 1.794%, respectively. Suitable ride condition with respect to forward speed, pulling force, and tillage depth is 0.6 m/s, 6 kN, and 0.14 m, respectively. The calculated response of linear and quadratic regression models show 1.747% and 1.224% error, respectively. The quadratic regression model is found to be the best suitable with 93% desirability.

Control of a multiple-DOF vehicle seat suspension with roll and vertical vibration

In this paper, the control of roll vibration and vertical vibration of a seat suspension caused by uneven road under both sides of tyres is studied. The heavy duty vehicles are generally working under severe conditions, where the uneven road can cause roll vibration and vertical vibration of the vehicle body and can have an effect on seat suspension. The conventional single-degree of freedom (single-DOF) seat suspension can only isolate the vertical vibration while the roll vibration will be totally transferred to the driver's body. The high magnitude of driver body's lateral acceleration caused by roll vibration will influence drivers' health and have a negative effect on ride comfort. A two-layer multiple-DOF active seat suspension, which has a z-axis DOF in the bottom layer and a roll DOF in the top layer, is proposed in this paper. A non-singular terminal sliding controller is designed to control the top-layer to reduce the lateral acceleration and roll acceleration by tracking a desired roll angle. An H∞ controller with disturbance compensation is applied to control the bottom-layer for vertical vibration isolation. Both controllers use the variables which can be measured or estimated in the practical application as feedback signals. Two inertial measurement units (IMUs) MPU9250 are used in order to estimate the rotary angles of the top and base platforms of the two-layer multiple-DOF active seat suspension. The effectiveness of the seat suspension and control method is validated by both simulations and experiments. A single-DOF active seat suspension and a well-tuned conventional passive one are applied for comparison. Based on ISO 2631, the vibration total value of frequency weighted root mean square (FW-RMS) acceleration of the multiple-DOF active seat surface has 29.8% and 23.6% reductions for evaluating its influence on health and ride comfort, respectively, when compared with the single-DOF active one. The proposed vibration isolation method can effectively reduce the whole body vibration (WBV) of heavy duty vehicle drivers, and it shows high potential for practical application.

Evaluation of Ride Comfort and Driving Safety for Moving Vehicles on Slender Coastal Bridges

Evaluating driving safety of moving vehicles on slender coastal bridges as well as bridge safety is important to provide supporting data to make decisions on continuing or closing the operations of bridges under extreme weather conditions. However, such evaluations could be complicated due to the complex dynamic interactions of vehicle-bridge-wind-wave (VBWW) system. The present study proposes a comprehensive evaluation methodology on vehicle ride comfort and driving safety on the slender coastal bridges subject to vehicle, wind, and wave loads. After a brief introduction of the VBWW coupling dynamic system and obtaining the dynamic responses of the vehicles, the vehicle ride comfort is evaluated using the advanced procedures as recommended in the ISO 2631-1 standard based on the overall vibration total value (OVTV). The vehicle driving safety is analyzed based on two evaluation criteria, i.e., the roll safety criteria (RSC) and the sideslip safety criteria (SSC), through the vehicle contact force responses at the wheels. Finally, the proposed methodology is applied to a long-span cable-stayed bridge for the vehicle ride comfort and driving safety evaluation.

Upper limb disorders and hand-arm vibration risks with hand-held olive beaters

Olive harvesting with hand-held beaters is a repetitive work, tiring and time consuming (more than 4–5 h/day). Operators work with vibrating tools in not natural body postures: they are therefore exposed to various risks, especially at the upper limbs. Unfortunately, also if in the agriculture sector the number of the declared upper limb disorders increased in the last years, hand-arm vibration and incongruent upper limb postures are not yet well perceived. In this work, the hand-arm vibration exposure and the OCRA index were calculated for five operators which used three different electric olive beaters. In all the observed tests both the hand-arm vibration and the OCRA scores produced results over the admitted limits. A(8) ranged between 8.6 ms-2 and 25.4 ms-2, far from the 5 ms-2 daily exposure limit values admitted by the European law (European Directive 2002/44). The OCRA checklist values ranged from a minimum value of 13.32 (red light level and light risk) for the left limb and a maximum of 34.41 (violet, high level and high risk) for the right limb. Relevance to industryThis paper describes the analysis of the combined risks to hand-arm vibration and to upper limb disorders in a typical agricultural harvesting task with a manual handled tool powered by electric engine. Tests were carried out during the olive harvesting with five operators using three different hand-held machines. Both vibration and OCRA parameters were acquired. Results showed that in all the observed tests both the hand-arm vibration and the OCRA scores were over the admitted limits. Beaters transmitted vibration to both the operators’ hand-arm system, but operators did not declare to perceive vibration at the right upper limb (because it was less affected by the vibration stimulus than the left one). To acquire reliable values for the upper limb biomechanical risk detection it should be necessary to use measured vibration data in field, avoiding personal judgments. When it is not possible to measure the vibration level, the employer should use the machine instruction, where the manufacturer should have written the vibration total value to which the hand-arm system is subjected, if it exceeds 2,5 m/s2 (European Directive 2006/42). When this information is not available in the machine instruction, the employer may refers to other sources (European Directive 2002/44), as databases provided by government or institutional bodies, including vibration values obtained by research specialists and vibration consultants.

Grass trimmer handle vibration reduction by imposing node method using vibration absorber

The purpose of this investigation is to apply imposing node technique for vibration reduction of petrol engine grass trimmer handle using vibration absorber. The algorithm is devised to find the required resonance frequency of the absorber to impose node at desired location on beam. The numerical simulations are performed to find the usefulness of absorber for imposing nodes at the handle attachment location on timer pipe. The experimental test is conducted to validate the numerical results and to evaluate the vibration suppression during no cutting and cutting conditions. The vibration total value measured at handle of grass trimmer shows that absorber is useful in handle vibration reduction.

Hand-arm vibration in orthopaedic surgery: a neglected risk.

Hand-arm vibration syndrome is an occupational disease caused by exposure to hand-arm transmitted vibration. The Health and Safety Executive has set limits for vibration exposure, including an exposure action value (EAV), where steps should be taken to reduce exposure, and an exposure limit value (ELV), beyond which vibrating equipment must not be used for the rest of the working day. To measure hand-arm transmitted vibration among orthopaedic surgeons, who routinely use hand-operated saws. We undertook a cadaveric study measuring vibration associated with a tibial cut using battery-operated saws. Three surgeons undertook three tibial cuts each on cadaveric tibiae. Measurements were taken using a frequency-weighted root mean square acceleration, with the vibration total value calculated as the root of the sums squared in each of the three axes. A mean (SD) vibration magnitude of 1 (0.2) m/s2 in the X-axis, 10.3 (1.9) m/s2 in the Y-axis and 4.2 (1.3) m/s2 in the Z-axis was observed. The weighted root mean squared magnitude of vibration was 11.3 (1.7) m/s2. These results suggest an EAV of 23 min and ELV of 1 h 33 min using this equipment. Our results demonstrate that use of a battery-operated sagittal saw can transmit levels of hand-arm vibration approaching the EAV or ELV through prolonged use. Further study is necessary to quantify this risk and establish whether surveillance is necessary for orthopaedic surgeons.