Variation in Single Number Ratings Due to Tapping Machine Location

In field testing of the impact noise insulation of floor-ceiling assemblies, single number ratings such as Impact Sound Rating (ISR) and L?n w are used to characterize the acoustical performance. A standard tapping machine generates the impact force on these assemblies, and the standard defines the requirements for defining the tapping machine locations. There are a significant number of tapping machine positions that satisfy the requirements of the standard. In this work, we have studied the impact of this variation in the tapping machine positions on the single number ratings. For the rooms tested, the L?n w rating can vary by four to five points, while the ISR and Low-frequency Impact Rating (LIR) may vary by three points, due to the variation in tapping machine positions.