Theoretical Justification for Modifying Homologation Standard ISO6395:2008(E) to Suit the Working Mine Site

Abstract

Measurement procedures for calculating sound power levels of mining equipment often include modifications to the formal requirements of ISO6395 for practicality and safety purposes on site. The formal procedures involving six measurement points are necessary for homologation certification against contractual requirements for the supply of mining equipment. This is a relatively minor percentage of the total number of sound power tests conducted within the Australian coalfields, however, as most testing is for ongoing compliance purposes where consent conditions require sound power testing of mining fleets every 2 or 3 years. Acoustical consultants have reported accurate results by using a reduced 4-point measurement regime which enables consent conditions to be met without undue disturbance to a mine’s operations. A theoretical basis for omission of two of the ISO measurement points is presented, as well as demonstration that a 2-point measurement regime is mathematically equivalent to the 4-point method. A correction for using sound pressure instead of sound intensity for calculation of sound power level is also calculated.