Hemi Anechoic Room Renovation
Cummins Emissions Solutions - Stoughton, WI
Project Features: Semi-Anechoic Room Renovation, Engine Aftertreatment Testing, Anechoic Chamber, NVH Testing, Noise and Vibration Product Development Lab

The Challenge
The scope of work for this project was to provide turnkey design and construction services for the interior renovation of the acoustic room.
In addition to all new acoustic treatments, the renovation of the hemi anechoic room included replacing the lighting system, expanding the number of compressed air drops, adding voice and data ports, and acoustic doors. Additionally, the electrical outlets were extended from the base of the wall to the surface of the acoustic treatments making them easier to access.
The Solution
The performance of the hemi anechoic room is qualified per ISO 3745 and has a cut off frequency of 63Hz. This is an improvement from the 125 Hz cut off frequency of the original design. The background noise level with the ventilation system in operation is 55 dBA re 20 uPa and below across all 1/3 octave bands. The background noise with the ventilation system turned off is 40 dBA re 20 uPa and below across all 1/3 octave bands.
The hemi anechoic room is designed to house the aftertreatment from engines in adjacent test cells. The engines are operated in the test cells with the exhaust piped into the hemi anechoic room where sound levels, thermal imaging, and back pressure measurements can be acquired.
Key Features
- Renovation of hemi anechoic room for engine emissions aftertreatment system research and development
- Acoustic doors and acoustic treatments specification and installation
- Hemi anechoic room is qualified per ISO 3745 and has a cut off frequency of 63Hz
- Sound levels, thermal imaging, and back pressure measurements can be acquired
ACS Services
ACS held a single-source contract for design and construction management; equipment specification procurement and installation; integration of equipment and facility systems; and commissioning.