Sponsor: 02.06 Sound and Vibration Control
Chair: Chris Papadimos, Member, Papadimos Group, San Rafael, CA

The seminar presents experiences of acoustic and vibration problems encountered in buildings associated with mechanical equipment and how they were solved. Attendees will appreciate common subtleties in equipment selection and installation and how to avoid potential pitfalls through some very simple but not so clearly obvious steps.

1. Acoustic and Structural Resonances
    Victor Wowk, P.E., Machine Dynamics, Inc., Rio Rancho, NM
    The acoustic resonance was a short duct section amplifying the blade passing tone of a fan that particularly
    bothered a blind woman in an office that relied on acoustic information to sense her surroundings. The solution
    was to slightly change the fan speed by re-sheaving. The structural resonance was stationary vanes vibrating on a
    vaneaxial fan resulting in a pure tone that was obnoxious in nearby offices. The supply fan was stopped and a    
    bump test found the stationary blades "sung" at 193 Hz. The solution was to modify the stationary blades thus
    ceasing to behave as a musical instrument.

2. Transmission Loss Testing of PTAC Units
    Jon Weinstein, P.E., Member, Industrial Acoustics Co., Inc., Bronx, NY
    Local noise code requirements can dictate acoustic performance requirements of ductless systems widely used in
    urban new construction and renovation projects. Noise transmission characteristics of these systems are discussed.

3. Controlling Audible Tones from Mechanical Equipment
    Roman Wowk, Student Member, Papadimos Group, San Rafael, CA
    What possibly could noise from computer room a/c units, fan coils, laboratory exhaust fans and screw chillers all
    have in common? Try audible tones! While the mechanisms that produce the tonal conditions differ, the end result     for the building occupants is the same – increased annoyance compared to uniform broadband noise. The
    contributing factors to the problem and the approach to remedial solutions will be presented with lessons learned.

4. Small Deviations and Big Failures in Vibration and Sound Isolation
    J. Byron Davis, Vibro-Acoustic Consultants, San Francisco, CA
    The difference between design intent and actual implementation is always a problem in real constructions. For
    vibration and noise isolation hardware, seemingly innocuous deviations can result in major deficiencies in
    performance. From hardware selection to installation and adjustment, isolation systems present significant
    challenges. In this presentation, we offer photographs gathered over the past five years of problematic rotating
    systems. Categories of failure are identified, and the photographic presentation highlights subtle errors that can
    lead to big problems later.


Sponsor: 02.06 Sound and Vibration Control, 02.01 Physiology and Human Environment
Chair: Kenneth P. Roy, Ph.D., Member, Armstrong World Industries, Lancaster, PA
 
This session presents the findings of two recent ASHRAE-sponsored projects that focused on the mechanical system noise in buildings, and the effects on human performance and perception. First, 1128-RP investigated how the noise levels and thermal conditions may interact to affect human performance and perception. Secondly, 1322-RP investigated the effects of ill-behaved noise, specifically conditions with tonal components or time-varying fluctuations, and discusses how the results can impact the indoor noise criteria listed in the ASHRAE HVAC Applications Handbook.

1. Combined Effects of Noise and Temperature On Human Comfort and Performance (1128-RP) (AB-10-017)
    Dale Tiller, Ph.D.1, Lily Wang, Ph.D., P.E., Member 2, Amy Musser, Ph.D., P.E., Member3 and Matthew J. Radik4,     (1)University of Nebraska, Lincoln, Lincoln, NE, (2)Architectural Engineering, University of Nebraska - Lincoln,         Omaha, NE, (3)Vandemusser Design, PLLC, Asheville, NC, (4)Union Pacific Railroad, Omaha, NE
    This paper presents the results of an investigation into the combined effects of noise from building mechanical
    systems and temperature on human comfort and performance.

2. The Effects of Noise From Building Mechanical Systems with Tonal Components On Human Performance and    
    Perception (1322-RP) (AB-010-018)
    Erica Ryherd, Ph.D., Member1 and Lily Wang, Ph.D., P.E., Member 2,
    (1)Georgia Institute of Technology, Atlanta, GA (2)University of Nebraska - Lincoln, Omaha, NE
    This paper presents the results of an investigation of noise from building mechanical systems with tonal
    components on human task performance and perception.

3. Human Performance and Perception-Based Evaluations of Indoor Noise Criteria for Rating Mechanical System    
    Noise with Time-Varying Fluctuations (1322-RP) (AB-10-019)
    Lily Wang, Ph.D., P.E., Member 1 and Cathleen C. Novak 2, (1)Architectural Engineering, University of Nebraska -     Lincoln, Omaha, NE, (2) PMK Consultants, Dallas, TX

    This paper presents the results on an investigation of noise from building mechanical systems with time-varying
    fluctuations on human task performance and perception. It also discusses how the overall findings of 1322-RP
    impact the indoor noise criteria ratings listed in the ASHRAE HVAC Applications Handbook.