Demolition & Construction Vibration: Is Measuring PPV Sufficient? Part 2 – Subjective Response
Subjective Effects of Demolition Vibration from Construction
With the publication of BS 6472 in 2008 construction vibration practitioners debated whether Vibration Dose Vale (VDV) should or could be used to assess and control the subjective effects of vibration from construction. When BS 5228: 2 was published in 2009 it contained a helpful table (B.1) of subjective effects vs. PPV. Although BS 5228: 2 stated that “if concern is purely for human tolerance, then weighted acceleration is the preferred parameter” it also said that “it is considered more appropriate to provide guidance in terms of PPV, since this parameter is likely to be more routinely measured” and “many of the empirical predictors yield results in terms of PPV”.
After the original publication of BS 5228: 2 in 2009 many (most?) practitioners therefore concluded that assessment and monitoring of the subjective response to construction vibration could be carried out using PPV alone.
Vibration Dose Values
In the 2014 amendment to BS 5228:2 substantial notes were added to Table B1. Note c) advises that the PPV values given in Table B.1 are “to give an initial indication of the potential effects” and that “where these values are routinely measured or expected then an assessment in accordance with BS-6472-1 or -2 and/or other available guidance might be appropriate to determine whether the time varying exposure is likely to give rise to any degree of adverse comment. “Degree of adverse comment” is, of course, a reference to the VDV categories set out in Table 1 of BS 6472: 1.
If the predicted or measured PPV levels are such that construction vibration will be perceptible it may be difficult justify not measuring VDV and carrying out an assessment in accordance with BS 6472:1.
Building Damage Risk Evaluation
In Part 1 of this discussion on demolition vibration and construction vibration it was concluded that measurement of PPV, dominant frequency and displacement (below a velocity dominant frequency of 4 Hz) were all essential for the evaluation of the risk of building damage in accordance with BS 5228: 2 and BS 7385: 2. Part 2 suggests that, in order to evaluate the subjective response to construction vibration in accordance with the advice in BS 5228: 2 and BS 6472: 1, evaluation of VDV is required in addition to PPV.