Page 31 - Volume 8, Issue 1 Winter 2013

than those with large systems that cannot easily be moved and generate low frequency sound.
During the 1980s and 1990s, the HVAC industry focused on system specific standards through the Air Conditioning, Heating, and Refrigeration Institute (AHRI), and reduced our activities at the Acoustical Society of America (ASA) and at the International Standards Organization (ISO). Thus, the base sound power standards moved away from addressing our needs.
Those present at the ASA or ISO standards activities often worked on computers or small appliances and tools that have different constraints and attributes. AHRI is currently working with the S12 Noise standards committee to create a new reverberation room standard that addresses the con- cerns and needs of HVAC manufacturers. We are spending more time now because we neglected this group for too long.
Avoiding conflict
During the 1990s the importance of acoustics of class- rooms received much attention within the acoustical com- munity. (See Fig. 2) Research was started or expanded, work- ing groups were formed, and a standard was written to deter-
2
The result was a negative reaction to the big changes in requirements. Had we been active, we would have been aware and ready for the changes, and we would have understood why they were needed. The reaction resulted in hard feelings and mistrust between the HVAC industry and many in the acoustics community. There was significant time and money spent by both sides to defend their respective positions.
3
In 2009 and 2010, the standard was revised. This time,
the HVAC industry was actively involved (working group co- chairs: Stephen Lind and Paul Schomer). We were able to bring the people involved together to understand better why the standard was important. Many people in the HVAC industry were educated on the requirements and the reasons behind them and subsequently moved from being opposed to the standard to a neutral position (with some companies strongly supporting the standard). The cost in time, dollars, and goodwill was much lower because of the collaboration.
Preparing for changing system requirements
Being involved early in the standards development process, such as seen in the classroom acoustics standard, helps everyone to be aware of what will be required. The standards often take multiple years to write, so being involved early provides time to adjust internal procedures about how to make measurements and calculations. The standards indicate what information to publish, so that sys- tem marketing materials can be organized and ready when the requirements take effect.
Knowing that a classroom will be required to meet a 35 decibel level allows us to guide customers on using our sys- tems to meet the goal. It also gives a design goal for systems that will be located inside the classroom where there is little that can be done to control the noise impacting the occu- pants. By being involved, we are more likely to understand and meet our customer’s needs.
Being active in standards work helps us to agree with our customers on what is the correct information to provide. Providing accurate, appropriate acoustical information for our solutions helps to make sure the system is applied cor- rectly and increases the likelihood that customers will be sat- isfied with our systems. Being proactive instead of reactive makes it easier to plan expenses and be ready for change.
Taking part in the process helps to avoid conflicts, which helps to improve relations with our customers. Being aware of new or upcoming requirements helps to make sure our system designs will be accepted in the intended markets. Having agreed upon standards helps both our customers and us.AT
References
1 P. Baade, History of the Qualification Procedures of American National Standard S1.21-1972, Noise Control Eng. J. 7 48–51 (1976)
2 ANSI/ASA S12.60-2002, American National Standard Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools (Acoustical Society of America, Melville, NY).
3 ANSI/ASA S12.60-2010/Part 1, American National Standard Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools, Part 1: Permanent Schools (Acoustical Society of America, Melville, NY).
.
mine the requirements regarding acoustics of classrooms. The HVAC industry was not actively involved. We were on the working group mailing lists; however, the effort did not get the attention it needed and we were surprised when the standard neared completion.
Fig. 2. Classroom background sound levels are significantly affected by heating, ven- tilation and air conditioning systems.
30 Acoustics Today, January 2012