A Noise Impact Assessment (NIA) is faster and less expensive than a Comprehensive Sound Survey (CSS). It provides a detailed analysis of a facility's contributing noise sources and their relative significance. It also specifies a course of action to reach regulatory compliance.
There are two primary types of NIA - Actual and Theoretical
Actual NIA - typically performed to investigate a complaint or when equipment is being added at an existing facility. On-site sound readings are taken to determine the exact sound power each item of equipment contributes.
Theoretical NIA - performed when building a new facility. Sound power data is compiled from manufacturer's equipment data sheets and Noise Solutions' acoustical database.
In both cases, the sound information is combined with topographical maps, weather data, manufacturers' data, and site operating conditions to calculate the actual noise on nearby residents. Unlike a CSS, the NIA targets the source and avoids setting up noise data recorders on residential property and waiting for ideal conditions.
Using leading-edge environmental noise propagation software, very specific and accurate predictions are made to determine actual noise levels at nearby residents or other points of interest. The NIA describes exactly how much each noise source is contributing to the noise at an affected location Allowing Noise Solutions Inc. to identify a specific course of action to reduce noise to a targeted level.
Source Order Ranking Table (SORT)
Both Theoretical and Actual NIA's will create a definitive Source Order Ranking Table (SORT), which will:
- Identify all contributing noise sources.
- Quantify and prioritize each source.
- Identify the specific contributing frequencies of each source.
- Facilitate the targeted design of the most practical and cost-effective noise solution.
NIA's vs. Rules of Thumb in Facility Applications
In Alberta, the ERCB requires an NIA for all new facilities and for modifications to existing facilities. Because noise analysis is very complex, Noise Solutions encourages all operators to conduct a thorough NIA to ensure your facility meets regulatory and resident's needs rather than taking chances with rules of thumb. At present the NIA is unique to Alberta applications but may soon be a reality in other parts of the world.