Which Whole Body Vibration Weightings Should I Use?
Measurements with HVM200 Human Vibration Meter
When measuring human vibration, it is important to use the correct weightings for your measurement situation to account for the different resonances within the human body. Following is a chart of common vibration scenarios with the appropriate frequency weighting factor for each axis. There are settings pre-programmed in the HVM200 for some vibration conditions. Note that in addition to the pre-programmed settings, a user can create and save custom settings as needed.
| Vibration Condition |
x-axis |
y-axis |
z-axis |
HVM200 Setting |
| Vibration transmitted through the seat, measured at the seat surface |
Wd |
Wd |
Wk |
ComfortSeat/ HealthSeat |
| Vibration transmitted through the seat on a fixed-guide transport system, such as a train or subway, measured at the seat surface |
Wd |
Wd |
Wb |
N/A |
| Vibration transmitted through the seat, measured at the seat back |
Wc |
Wd |
Wd |
ComfortBack / ComfortMod |
| Vibration transmitted through the seat for a fixed-guide transport system, such as a train or subway, measured at the seat back |
Wc |
Wd |
Wb |
N/A |
| Vibration transmitted at the feet for a person in a seated position |
Wk |
Wk |
Wk |
ComfortFeet |
| Vibration transmitted through the floor to a standing person |
Wd |
Wd |
Wk |
N/A |
| Vibration transmitted through the floor under the pelvis to a person in a prone position |
Wd |
Wd |
Wk |
N/A |
| Vibration transmitted through the floor under the pelvis to a person in a prone position when on a fixed-guide transport system, such as a train or subway |
Wd |
Wd |
Wb |
N/A |
| Vibration transmitted through the floor at the head to a person in a prone position |
Wj |
Wd |
Wk |
N/A |
| Vibration transmitted through the floor at the head to a person in a prone position, when on a fixed-guide transport system, such as a train or subway |
Wj |
Wd |
Wb |
N/A |
| Whole body vibration in buildings |
Wm |
Wm |
Wm |
WmBuilding |
| All hand-arm vibration measurements |
Wh |
Wh |
Wh |
Hand-Arm |
| Rotational vibrations for a seated person |
We |
We |
We |
ComfortRot |
For further reference, these are the frequency weightings defined by ISO 2631-1
| Frequency Weighting |
ISO 2631-1 Definition |
| Wb |
z-axis vertical vibration, seated, standing, or recumbent for fixed-guide transport systems |
| Wc |
x-axis, horizontal, seat back, seated person |
| Wd |
Horizontal whole body, x- or y-axis, seated, standing, or recumbent; z-axis seated (at seat back) |
| We |
Rotational, all directions, seated person |
| Wf |
Vertical whole-body, z-axis motion sickness (for low-frequency whole body vibration signals), seated or standing |
| Wh |
Hand-arm, all directions |
| Wi |
Vertical head vibration, x-axis, recumbent person |
| Wj |
Vertical whole body, z-axis seated (at seat surface), standing, or recumbent |
| Wm |
Whole body in buildings, all directions |