The current standard EN50144 which is used by all powertool manufacturers measures vibration in a dominant axis ( otherwise known as a single-axis measurement).
The new measurement standard BS EN ISO 5349-1:2001 (prEN60745-1:2005) which measures vibration in three directions (otherwise known as the tri-axial or vector sum measurement) has been developed to replace the existing EN50144 (single-axis)standard. This will bring the manufacturers vibration measurement procedures in line with the Physical Agents HAV Directive.
The new BS EN ISO 5349-1:2001 Standard measures vibration in three directions or more commonly known as the tri-axial value
NOTE – Not all product groups have Tri-Axial measurement standards available. See page 3 in this section for more detail.
The new measurement is calculated by
"m/s²=vX²+Y²+Z²