CTI Updates Sound Measurement Test Code ATC-128


The Cooling Technology Institute has released an updated version of Acceptance Test Code 128, Measurement of Sound from Heat Rejection Equipment, which is the industry’s recognized standard specifically for published sound data provided by manufacturers of package cooling towers used on HVAC, industrial and process cooling systems. The improved technique for sound power calculation can now be applied to virtually all factory-assembled heat rejection equipment, including open- and closed-circuit cooling towers, evaporative condensers, adiabatic fluid coolers/condensers and air-cooled (dry) coolers/condensers.  Other changes, including updates to equipment calibration requirements, were made to better align with future sound certification programs.


An updated version of ATC 128 has been released by the Institute has released an updated version of Acceptance Test Code 128.

This new update builds upon the 2019 edition, which revised the sound emission surfaces along with the associated sound power equation. With this updated method, sound power results are more indicative of other international test codes. This change was adopted after extensive research, sound modeling, product testing and comparisons with various internationally recognized sound codes.

In August 2023, cooling tower and other heat rejection equipment manufacturers voted unanimously in the ATC-128 Committee meeting that they will voluntarily publish sound power levels per the latest version of ATC-128 (now March 2024). To reinforce this, ATC-128 was also modified to require all sound ratings should clearly state the test code and year used for the ratings. Users of sound data are urged to check the sound rating method listed on the data sheets provided by manufacturers, which will define the version of ATC-128 that has been used to calculate the listed sound power levels.

Larry Burdick, Chair of the ATC-128 Committee, said “This continuing agreement, along with the new ATC-128 requirements, will assist those individuals comparing ratings on a given project that the sound values provided by various suppliers are truly comparable.”

So when asked “What’s in your sound rating?”, the answer for factory-assembled heat rejection equipment should now be sound data calculated per ATC-128 (March 2024). Should an end-user determine the sound ratings provided are not per the latest version of ATC-128, they should contact the CTI Administrator for an investigation.

ATC-128 is available in the CTI Marketplace.

Details of the research, testing and modeling documented in various technical papers, the 2019 educational seminar and task group records are also available from CTI.  In addition, CTI licensed sound test agencies are available to perform acceptance tests per the updated document.


About Cooling Technology Institute

The Cooling Technology Institute is a broad-based industry association. Our mission is to advocate and promote, for the benefit of the public, the use of all environmentally responsible commercial cooling technologies such as wet cooling towers, air-cooled condensers, dry coolers, indirect cooling and hybrid systems by encouraging education, the development of codes, standards and guidelines, the use and oversight of independent performance verification and certification programs, research and development, information exchange, and dialog with government agencies and organizations with a shared interest in evaporative heat rejection equipment. For more information, visit https://www.cti.org