Vibration Exposure Calculator
Plan your environmental & safety project with our free vibration exposure calculator. Get precise measurements, material lists, and budgets.
Reviewed by Abdullah, Technical Content Specialist
Formula
A(8) = a_hv x sqrt(T / T0) x K
The daily vibration exposure A(8) is calculated by multiplying the vibration magnitude (a_hv in m/s2) by the square root of the exposure duration (T) divided by the reference duration (T0, typically 8 hours), and optionally by a correction factor K. The result is compared against the Exposure Action Value of 2.5 m/s2 and the Exposure Limit Value of 5.0 m/s2.
Worked Examples
Example 1: Angle Grinder Exposure
Problem:A worker uses an angle grinder with vibration magnitude of 6 m/s2 for 4 hours in an 8-hour shift.
Solution:A(8) = 6 x sqrt(4 / 8) = 6 x 0.707 = 4.24 m/s2\nExposure points = (6 / 2.5)^2 x (4 / 8) x 100 = 288\nMax time at EAV = 8 x (2.5 / 6)^2 = 1.39 hours
Result:A(8) = 4.24 m/s2 (above EAV, below ELV)
Example 2: Pneumatic Drill Full Shift
Problem:A construction worker operates a pneumatic drill with 12 m/s2 vibration for 2 hours.
Solution:A(8) = 12 x sqrt(2 / 8) = 12 x 0.5 = 6.0 m/s2\nExposure points = (12 / 2.5)^2 x (2 / 8) x 100 = 576\nMax time at ELV = 8 x (5.0 / 12)^2 = 1.39 hours
Result:A(8) = 6.0 m/s2 (exceeds ELV of 5.0)
Frequently Asked Questions
What is hand-arm vibration exposure A(8)?
A(8) is the daily vibration exposure value normalized to an 8-hour reference period. It is calculated by multiplying the vibration magnitude by the square root of the ratio of actual exposure time to the reference period. This standardized metric allows comparison of different exposure durations and is the primary value used in occupational health regulations across Europe and many other jurisdictions.
What are the EU exposure action and limit values for vibration?
Under EU Directive 2002/44/EC, the Exposure Action Value (EAV) is 2.5 m/s squared for hand-arm vibration, which triggers employer obligations for health surveillance and risk reduction. The Exposure Limit Value (ELV) is 5.0 m/s squared, which must not be exceeded under any circumstances. Employers must take immediate action to reduce exposure below the ELV if it is reached or exceeded.
How do I measure vibration magnitude for a power tool?
Vibration magnitude is typically provided by the tool manufacturer in the equipment documentation, measured in meters per second squared (m/s2). You can also measure it directly using a tri-axial accelerometer mounted on the tool handle. The declared vibration value from manufacturers is measured under standardized test conditions and real-world values may be higher, so a correction factor (K factor) of 1.0 to 2.0 is often applied.
References
Reviewed by Abdullah, Technical Content Specialist · Editorial policy