Human exposure to noise and its ill effects have always drawn more attention and importance over the vibration related activities. So much so, that the first set of guidelines for noise doze levels were published as early as 1930s for automotive and aeronautical industries. The occupational safety and health act OSHA was conceived in the year 1970 and many inclusions and refinements have been done to this rule book.


In contrast, standards & guidelines on human exposure to vibrations are only being truly implemented since early 2000; beyond the cars and aircrafts, there are many engineering segments wherein the human is directly in contact with of machinery and equipment that are much likely to cause significant exposure hazard, both for short- and long-term operations.


Hand drills to jack hammers, farm equipment to power tools, new generation tools to utilities used in construction/ allied activities, all generate and transmit damaging vibration energy to the human body.


The broad category of human centric vibrations is classified under HAND ARM (HA) vibrations and WHOLE BODY (WBV) vibrations; as the word goes, hand arm vibrations are applicable wherein the equipment is held by the operator using his hands and the whole body is when the human body is directly in contact with the vibrating surface. The combination of HA and WBV also exist as a case in many applications.


From temporary numbing of palm & hand body parts, white finger syndrome to serious neurological problems, many damaging effects are associated with HA and WBV. Increased concerns of these negatives have brought in comprehensive guidelines and standards that govern how the HA and WBV are to be quantified and certified for their safe use.


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The assessment method is usually made with specific seat adapters (WBV) and hand / finger gripping accessories (HA); vibration sensors in three orthogonal directions (with Basi-centric co-ordinates) are configured as an integral part of the seat or hand adaptor. With the equipment in operation and the human exposure to vibration in place, measuring instruments either would do a direct rating of the exposure levels or will record vibration accelerations for post analysis, in both cases using specific weighting filters that determine vibration exposure levels as a function of frequency and time.


With a considerable size of work force and significant activities in construction domain on an increase in developing countries like India, its time and relevant to have these vibration exposure guidelines firmly in place and its implementation done in its true earnest.


NV Dynamics works with many of product design centres in defining the HA and WBV values upfront; the association goes on till the product validation is done with tests and iterations to see that better value-added products are made and are field worthy for their human specific vibration compliance.