Development of a Simple Construction Site Noise-Prediction Procedure
Community & Cultural Concerns, Environmental Process
Research Idea Scope
TERI Administrator Note (Feb 2009) – Research Complete –
Related research: The FHWA Roadway Construction Noise Model (FHWA RCNM) Version 1.0 is a Windows-based program that is available without cost or obligation for use in predicting noise for highway construction projects of varying complexity. (www.rcnm.us) The intended use for the FHWA RCNM is as a construction noise screening tool. It is based on a noise prediction spreadsheet developed for the Boston CA/T. The FHWA RCNM predicts noise from highway construction operations based on a compilation of empirical data and the application of acoustical propagation formulas. It enables the calculation of construction noise levels in more detail than manual methods while avoiding the need to collect extensive amounts of project-specific input dataTemporal changes in noise as equipment cycles through work operations are currently only estimated from acoustic usage factors, or the percentage of time that equipment is working at full power. Thus, the current method of modeling construction noise using metrics of interest, such as Leq or L10 percentile levels, provides coarse estimates at best.
Noise modeling in general use today stem from Environmental Protection Agency methods promulgated in the 1970s that are based on noise-emission source strength levels associated with generic types of equipment. Shortcomings in the current model include existing equipment noise databases that are expressed only as maximum (Lmax) broadband A-weighted emission levels, which oversimplify the importance of frequency (tonal) effects and do not address warning devices such as back-up alarms. Fortunately, modern noise-measurement instrumentation, combined with the unique field
data collection opportunities at numerous construction projects, provides an opportunity to quickly develop a much-improved construction equipment noise database and prediction model algorithm on a spectral basis. The frequency-dependent effects of noise barriers, distance and ground losses, atmospheric absorption, and interaction with structures or buildings can be modeled much more accurately. Defining a variety of generalized, process-related construction activities could potentially eliminate usage factors.
Resulting construction noise predictions can still be evaluated against established noise-criteria limits, which are typically expressed in broadband (A-weighted) levels. It is envisioned that such a model can be developed in spreadsheet format or as a new TNM module. Input geometries in the model could be graphical or tabular (as with TNM), and construction equipment of interest could be selected from database lookup menus.
Urgency and Payoff
Transportation Research Board 2002 Environmental Research Needs Conference Notes