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HAV calculator
You can open the calculator here: HAV calculator ...
... and this is the geeky part, where I explain the underlying maths:
Daily exposure
The basis for the calculator is the equation (from ISO 5349):
A(8) = ahv SQRT (T/T0)
where:
ahv is the h-weighted acceleration total value (m/s²);
T is the total daily exposure time;
T0 is the reference exposure time of 8 hours (28800 seconds).
Exposure Points
To get exposure points values, the HSE system is based on 100 points being the equivalent of A(8) = 2.5 m/s². This is the Exposure Action Value (EAV) defined in the Control of Vibration at Work Regulations 2005.
The equation for the Points Exposure PE value is then:
PE = 100 . (ahv/EAV)² . (T/T0)
Adding exposures
To add daily exposure from difference machines or processes, the individual partial vibration exposures cannot be simply added together, daily exposure is given by:
A(8) = SQRT(A1(8)²) + A2(8)²) + A3(8)²) + ...)
The advantage of the exposure points system is that partial exposure points can be easily added, so daily exposure points is given by:
PE = PE,1 + PE,2 + PE,3 + ...
If necessary, conversion from points to daily exposure in dB(A) is given by:
A(8) = EAV . SQRT(PE/100)
HAV Lookup
You can lookup indicative HAV values here: HAV lookup ...