Noise Integrated Routing System (NIRS) Version 6.1

The Noise Integrated Routing System (NIRS) is a noise-assessment program designed to provide an analysis of air traffic changes over broad areas. It is intended to work in conjunction with other Air Traffic modeling systems that provide the source of routes, events, and air traffic procedures such as altitude restrictions.

The outputs of NIRS include population-impact and change-of-exposure reports and graphics. Population centroids are evaluated as improved or worsened based on their change of exposure. A hierarchy of rules based on FAA guidance and local requirements are then employed to determine if an airspace alternative is likely to be controversial based on noise considerations. Where possible, the system identifies the principal source of the change of exposure. Having identified the route set responsible for an increase, the air traffic planner can begin the evaluation of possible mitigation alternatives.

Background
NIRS was first developed in 1998 and is currently the FAA's standard regional noise model, which efficiently addresses the large scale requirements of modeling aircraft noise effects over multi-state regions. Current capabilities provided by NIRS are:

• Altitude-control logic that enables NIRS aircraft to follow user-specified tracks in three dimensions, or to follow “standard” profiles wherever these are consistent with the airspace design;
• Annualization logic that enables NIRS to mix traffic from different operational configurations in the ratios appropriate to represent average annual airspace and runway usage;
• The NIRS impact table and impact graph to quantitatively assess differences in noise impacts between alternative airspace designs using specific FAA noise-impact criteria;
• Change-analysis logic that enables NIRS to specify which traffic elements (out of the many hundreds in regional studies ) are causing significant noise impacts;
• Various map-based tools for display and query of the underlying track and noise data

NIRS functions and provides familiar menu options. It is intended to have the same look and feel as other window-oriented applications. The main window provides the interface to all of the NIRS programs that:

• Build and organize a study;
• Provide error checking of all inputs and outputs;
• Perform the noise computations;
• Enable the user to analyze impacts and trace their causes; and
• Format the output for reports and graphics that may be used in applications such as Microsoft Word, Microsoft Excel, and Microsoft PowerPoint.

Model Inputs
NIRS applications are organized as projects. A NIRS project contains all of the input files, output files, reports, and graphics necessary to complete the noise analysis. NIRS utilizes the following inputs:

• Runway Data
• Population Census Data
• Grid Data
• Scenarios or Design Alternatives
• Airspace Routes
• Traffic Files

System Requirements
The current version of NIRS is designed to work on a PC-compatible computer with the Linux or Microsoft Windows operating system. The Linux operating system must be either the RedHat 9.0 or greater distribution or an equivalent alternative Linux distribution. The Windows operating system must be Windows XP SP2 or greater. At least 512 MB of RAM are suggested. Approximately 4 MB of free space are necessary to install the NIRS software. Smaller projects may require less than 100 MB of disk space, but larger ones may require more. The noise computation engine has been ported and run on many systems including personal computers, all ranges of workstations, and super-computers.

Availability
NIRS is available for fee from FAA’s NIRS distributor, Metron Aviation. Please the link below for the Order Form.

• NIRS Order Form (PDF, 12 KB)