Hand-Transmitted Vibration Analysis Object (Human Body Vibrations Option)
This analysis object is used to analyze hand-transmitted vibrations that are transferred from vibrating tools through the palms and fingers to the hands and arms. These vibrations can damage the tissues of the hands and arms. If a person is exposed to strong vibrations, this presents risks to his health and safety. The risks are greatest when the vibration magnitudes are high, the exposure durations long, frequent, and regular, and the vibration includes severe shocks or jolts.
The results of the analysis object are used to evaluate the risks caused by vibration. The directives and standards include exposure limit values that can be compared to the assessed results. In this way you can determine whether safety measures for eliminating or reducing the effects of vibration are necessary.
Vibration Direction
The acceleration signals already calibrated are used as input signals. You can use the vibration direction to specify whether a signal measured in the X,Y or Z direction is analyzed or whether the signals measured in the X, Y and Z direction are to be used together for analysis.
The first step in the analysis consists of assessing the frequencies of the acceleration signals. This can be done both in the time domain as well as in the frequency domain (e.g. weighting of third octave bands). In FlexPro, filtering takes place in the time domain. The frequency weighting Wh is used for all directions for hand-transmitted vibration analysis.
Output Options
The analysis object offers a variety of output options that can be used to evaluate the effects of vibration on the human body. Scalar values are used except for in the case of the frequency-weighted acceleration signal. Since the results are output as a list, you can use the List Element operator to access the individual elements.
The following output options are available for individual directions of vibration:
Option |
List Element Name |
Description |
|---|---|---|
Frequency-weighted acceleration signal |
.["FrequencyWeightedSignal_X"] |
The calibrated acceleration signal is filtered with the frequency weighting wh . |
Frequency-weighted acceleration ahw |
.["ahw_X"] |
The square mean (RMS value) of the frequency-weighted acceleration signal provides the frequency-weighed acceleration ahw. |
Daily exposure A(8) |
.["A8_X"] |
This refers to the equivalent continuous acceleration, normalized to an 8-hour day. The value is used for assessing the daily exposure to vibrations. |
Time until the exposure action value of A(8) is reached |
.["EAV_TIME_A8_X"] |
The time until the daily exposure A(8) reaches the exposure action value of 2.5 m/s2 . |
Time until the exposure limit value of A(8) is reached |
.["ELV_TIME_A8_X"] |
The time until the daily exposure A(8) reaches the exposure limit value of 5 m/s2 . |
Additionally, the following output options are available in case acceleration signals are present in the X, Y and Z directions:
Option |
List Element Name |
Description |
|---|---|---|
Vibration total value ahv |
.["ahv"] |
Vector sum from the three determined frequency-weighted accelerations in the X, Y and Z direction. |
Daily exposure A(8) total |
.["A8"] |
Corresponds to the vibration total value, normalized to an 8-hour day. |
Exposure Duration
The exposure duration is required for calculating the daily exposure A(8).
Note:
If several partial measurements are used for calculating the daily exposure, the partial results can be calculated using the analysis object. At the end, an FPScript formula needs to be developed to calculate the total result from the partial results. The Analysis Wizard creates this formula automatically. Up to 5 signals can be calculated per direction, stating the respective exposure duration.
The exposure action value and exposure limit value used conform to Directive 2002/44/EC. There is a risk of damage if the exposure action value is exceeded. It is the responsibility of the employer to ensure that the risks caused by hand-transmitted vibrations are eliminated or reduced to a minimum. If the daily exposure limit value is exceeded, immediate measures are required and employment of workers is prohibited.
Observed Standards
Standard |
Description |
|---|---|
ISO 5349-1:2001 |
Mechanical vibration - Measurement and evaluation of human exposure to hand-transmitted vibration - Part 1: General requirements |
Directive 2002/44/EC |
on the minimum health and safety requirements regarding the exposure of workers to the risks arising from physical agents (vibration) |