Floor covering standards based on improvement of impact insulation ratings

Abstract

A common acoustical design task is predicting the impact rating of an existing floor system that is modified by adding or changing flooring elements. Most codes and regulations are based on impact testing of the resultant system. It might seem that floor coverings could instead be specified using laboratory testing of the improvement in impact sound insulation of floor coverings (ΔIIC test) per ASTM E2179. However, in practice the ΔIIC rating does not accurately predict the resultant assembly. Here, we investigate several avenues that may allow improved prediction of impact ratings. The first path is modification the ΔIIC rating by removing the rule limiting the deficiency in any third-octave band to 8 dB (“the 8 dB rule”). The 8 dB rule has been shown to result in a 4-point bias of the ΔIIC rating, which may account for a large portion of the inaccuracy. A second path is using the high-frequency impact rating, ΔHIIC instead of ΔIIC, which is promising since flooring improvements are largely limited to the high-frequency range. A third path is defining a standard lightweight (i.e., wood-framed) reference floor to complement the existing concrete reference floor. These investigation may yield impact requirements for flooring that are easier to understand, specify, and verify.