SCHEDULE 2Whole-Body Vibration

Regulations 4(2) and 6(5)

Part I-Daily exposure to vibration

The daily exposure to vibration (A(8)) of a person is ascertained using the formula:

A(8)=kawTT0math

where:

  • aw is the vibration magnitude (root-mean-square frequency-weighted acceleration magnitude) in one of the three orthogonal directions, x, y and z, at the supporting surface;

  • T is the duration of exposure to the vibration magnitude aw;

  • T0 is the reference duration of 8 hours (28,800 seconds); and

  • k is a multiplying factor.

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).

Daily exposure to vibration (A(8)) is evaluated separately for the x, y and z directions of vibration.

For horizontal vibration (x and y directions), k = 1.4 and aw is obtained using the Wd frequency weighting. For vertical vibration (z direction), k = 1.0 and aw is obtained using the Wk frequency weighting.

Definitions for the frequency weightings are given in International Standard ISO 2631-1:1997.

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:

A(8)=1T0∑i=1nawi2Timath

where:

  • n is the number of individual operations within the working day;

  • awi is the vibration magnitude for operation i; and

  • Ti is the duration of operation i.

Part II-Exposure to vibration averaged over one week

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:

A(8)week=15∑j=17A(8)j2math

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).