HVI Press Release

The Home Ventilating Institute (HVI) Adopts Six-Mic Array Method for Sound Testing at Energy Systems Lab (ESL)

In September 2008, The Home Ventilating Institute (HVI) employed a consultant to consider how to reduce background noise levels at HVI-designated testing facilities. The focus of the research was to obtain background noise level steadiness and the results were better than expected. "We found the rotating boom was the major background noise source – and that it can be eliminated," said John Harper, HVI Board Director and Engineering Committee Chairman. "Tests showed that background noise levels without the boom were five to ten decibels (dB) lower than those with the boom. This is tremendously significant when testing quiet fans."

For accurate and repeatable sound measurement, it is important that background sound in the sound chamber be less than that of the product being measured. In other words, quiet fans need an unusually quiet background to yield the best results. The results from this research yielded a change in the way HVI will be certifying all products going forward. HVI's primary testing facility, Energy Systems Lab (ESL) located at Texas A&M University, has replaced its rotating boom with an array of six microphones. The necessary equipment has been purchased and was installed, calibrated and qualified last month. HVI Publication 920© Product Performance Certification Procedure Including Verification and Challenge now requires manufacturers of low-sone products (less than 1.5 sones) desiring HVI Certification to have their products tested using the six-mic array.

The benefits of changing from a rotating boom to a six-microphone array include:

• Reduced background noise
• More effectively averaged standing waves
• Enhanced repeatability in testing
• More accurate results

"Switching from a rotating boom to a six-microphone array is a clear indicator that HVI is willing to adapt, accept and utilize new, but proven technology in order to keep the certification program relevant and acknowledged as the premier certification program in the industry," said Harper.

The Home Ventilating Institute (HVI), founded in 1955, is a nonprofit association of the manufacturers of home ventilating products. Through its Certified Ratings Program, HVI provides a voluntary means for residential ventilation manufacturers to report comparable and creditable product performance information based upon uniformly applied testing standards and procedures performed by independent laboratories.

Today, HVI represents manufacturers from the United States, Canada, Asia and Europe, producing the majority of the residential ventilation products sold in North America. For more information, contact HVI at 1000 N. Rand Road, Suite 214, Wauconda, IL, USA 60084. Telephone: 847.526.2010; fax: 480.559.9722. Visit the website at www.hvi.org.

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