ISO 7916:1989
Forestry machinery; portable brush-saws; measurement of hand-transmitted vibration
- Standard No.
- ISO 7916:1989
- Release Date
- 1989
- Published By
- International Organization for Standardization (ISO)
- Status
- Latest
- ISO 7916:1989
- Scope
- This International Standard specifies general methods for data acquisition and processing concerning hand-transmitted vi- brations induced by portable hand-held, combustion engine brush-saws for use primarily in forestry. The methods are valid irrespective of how the brush-saw is operated during the test, for example, whether it is hand-held or fitted in a stand, and whether it is cutting or not. This International Standard specifies an operator hand-held procedure for acquisition of vibration data from portable brush- saws. NOTES 1 The hand-arm system exerts an influence on the hand-transmitted vibration, and different hands and grips exert different influences. Therefore, the development of a standardized stand for holding the saw during the measurement is in progress. 2 The measurements in the three axes should be made at, or clearly related to, the surface of the hands where the energy enters the body. As the hands of the person are in direct contact with the vibrating surface of the hand grip, the transducer should be fastened to the vibrating structure. This International Standard is primarily intended for user and manufacturer purposes. NOTE 3 - For definitions of terms relating to portable brush-saws, see IEC 651 : 1979, Sound level meters. 3 Data acquisition and processing 3.1 Weighted acceleration sum The acceleration in three perpendicular directions (defined in clause 4) shall be picked up by accelerometers and processed to form an overall vibration value, the weighted acceleration sum (a,& according to figure 1. Mathematically ah,, is the mean square of the root (RMS) of the weighted signals from each direction. The weighting filters shall have the characteristics given in ISO 5349. (The definition of the weighting filter is given in annex A.) NOTES 1 The weighted acceleration sum combines the vibrations from all three axes and should not be compared with the single axis value of 2 ah,W can be calculated from frequency spectra of l/3 octave or l/l octave with the weighting factors for the mid-frequencies calculated from ISO 5349. [The l/3 octave analysis will be the most accurate.) 3 To obtain more detailed information about the vibration level, the evaluation according to ISO 5349 should be carried out. (The 113 octave analysis will give the most detailed information.) 4 The three different acceleration directions may be measured at dif- ferent times, but under the same operating conditions. 3.2 Mass of accelerometers
ISO 7916:1989 history
- 1989 ISO 7916:1989 Forestry machinery; portable brush-saws; measurement of hand-transmitted vibration
