Regulations 4(1) and 6(5)
SCHEDULE 1E+W+SHand-Arm Vibration
Part I-Daily exposure to vibrationE+W+S
The daily exposure to vibration (A(8)) of a person is ascertained using the formula:
where:
ahv is the vibration magnitude, in metres per second squared (m/s2;);
T is the duration of exposure to the vibration magnitude ahv; and
T0 is the reference duration of 8 hours (28,800 seconds).
To avoid confusion between vibration magnitude and daily exposure to vibration, it is conventional to express daily exposure to vibration in m/s2 A(8).
The vibration magnitude, ahv, is ascertained using the formula:
where:
ahwx, ahwy and ahwz are the root-mean-square acceleration magnitudes, in m/s2, measured in three orthogonal directions, x, y and z, at the vibrating surface in contact with the hand, and frequency-weighted using the weighting Wh.
The definition for the frequency weighting Wh is given in British Standard BS EN ISO 5349-1:2001.
Where both hands are exposed to vibration, the greater of the two magnitudes ahv is used to ascertain the daily exposure.
If the work is such that the total daily exposure consists of two or more operations with different vibration magnitudes, the daily exposure (A(8)) for the combination of operations is ascertained using the formula:
where:
n is the number of individual operations within the working day;
ahvi is the vibration magnitude for operation i; and
Ti is the duration of operation i.
Part II-Exposure to vibration averaged over one weekE+W+S
The exposure to vibration averaged over one week (A(8)week) is the total exposure occurring within a period of seven consecutive days, normalised to a reference duration of five 8-hour days (40 hours). It is ascertained using the formula:
where:
A(8)j is the daily exposure for day j.
The exposure to vibration averaged over one week is for use only for the purposes of Regulation 6(5).