Uncertainty Analysis of Environmental Sound : Analysis of a Series of Experiments

A series of experiments used attended and unattended instruments at two primary sites: (i) adjacent to the A428 (a second-tier road), and (ii) adjacent to the West Coast mainline railway. These are both rural sites, so that the traffic / rail noise will tend to dominate even at some distance from the noise source. Various configurations of monitors at different distances from the noise source, on different days and for different times were tested, and sound measurements were integrated over 5-minute (road) or 1-minute (rail) periods. At each site a series of measurements were taken during July and August in two separate years, which included several 4-day sets, using two different types of noise meter. The underlying aim of the project was to develop a simple ‘uncertainty’ budget for the measurement of environmental noise. The primary interest was in determining day-to-day variation, differences between instruments (at the same position), and differences between measurements at different distances from the source. One set of experiments also tested the difference between measurement positions chosen by different engineers.