# Guide to using the on-line hand-arm vibration exposure calculator

1. The calculator may be used online or, if you prefer, you can download and save it on your computer as a spreadsheet file (Microsoft Excel).

2. Click on the white areas and type in a vibration magnitude (in m/s2) and an exposure duration (in hours and/or minutes). You can do this for up to six different tools or processes.

3. When you have entered all the numbers, press the ENTER key, or click on a different cell. The following values will then be calculated and displayed in the yellow cells on the right.

• The Partial exposure is the vibration exposure (shown in both m/s2A(8) and exposure points) for each individual tool or process, and is calculated from the Vibration magnitude and the Exposure duration.
• The Total exposure, also given in m/s2A(8) and exposure points, is calculated from the Partial exposures.

4. In addition to the partial and total exposure values, the calculator also uses the vibration magnitudes to produce the following values:

• Exposure points per hour . The number if exposure points for every hour of exposure time for the individual tool or process.
• Time to reach EAV (exposure action value). This is the total exposure time required for the individual tool or process, before the exposure action value (2.5 m/s2A(8) or 100 points) is reached.
• Time to reach ELV (exposure limit value). This is the total exposure time required for the individual tool or process, before the exposure limit value (5 m/s2A(8) or 400 points) is reached.

5. The illustration below shows the calculator in use. In this example, three tools are used by an operator during a working day. The vibration magnitudes are 10, 6 and 3.5 m/s2and the total exposure times are 15, 30 and 90 minutes respectively. These values have been typed into the white cells (you can use hours, minutes or a combination of the two for the exposure duration). The results (in the yellow cells) show the partial exposure values for the three tools and the total exposure which, at 2.8 m/s2 A(8) or 123 points, is above the exposure action value.

Q. The action and limit values are given a 8-hour equivalent values, A(8), but my employer works for more than 8 hours / works less than 8 hours per day. How do I determine their exposure?

A. The A(8) value is an "8-hour equivalent" value and is not directly dependent on how long someone is at work. Most workers have vibration exposures that change over the working day. The A(8) value allows us to compare average daily exposures. If someone works for just 45 minutes a day using a tool with a vibration level of 4 m/s² they will have the same daily exposure as someone who works for 12 hours a day with a tool producing 1m/s². We choose to express this as the A(8) daily exposure value which, in both of these example cases, is 1.2 m/s²A(8) (or 24 points).

6. The cells can be cleared for another calculation by clicking on the Reset button in the bottom right hand corner.

Note: When you open the spreadsheet you may see a Microsoft Excel message asking you to decide whether to enable or disable macros. If your system settings allow it, you should enable macros. If not, the Reset button will not work, but the white cells can still be cleared by manually deleting their contents.

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2014-12-09