LEAD — The Historic Homestake Opera House board still has some work to do to ensure that a proposed chiller meets noise requirements, before the city will approve its latest plan for expansion.
In a historic meeting on the opera house stage on Monday, the city delayed an official decision about giving a small portion of land to the opera house, pending clarification that the opera house board can meet the city’s existing noise ordinance. The land donation on the east side of the building would facilitate construction of an equipment elevator and the placement of chillers for the building’s air conditioning system. But some questions about how the opera house plans to keep the chiller noise down on the north side of the property remained unanswered, prompting Mayor Ron Everett to ask Historic Homestake Opera House board president Jay Jacobs for “something in writing” that would give the commission assurance of a plan that complies with city ordinance.
Current city ordinance says that the noise level in a commercial area has to be at 70 decibels at the property line, but continuous noises — such as what the chillers will generate — must be at 65 decibels.
Chris Heiser, a structural engineer with TSP Engineering in Rapid City, which is handling the opera house design plans, said an option to build a “Cadillac” chiller, which will include whisper fans and blankets, as well as a chain link fence, meets those requirements with 57 decibels on three of its four sides. However, the north side of the chiller is only five feet from the property line and therefore the noise is much louder, at about 85 decibels.
Heiser informed the commission that the opera house board is exploring options to reduce the noise level for the chiller on the north side, including possibly building a masonry wall or a wooden enclosure. The masonry wall, he said would be very difficult due to the supports that would need to be buried in an area that already has several underground utilities.
Dennes Barrett, who lives near the area where the opera house will place the chiller, told the commission that the opera house, Stampmill, and the Old Town Hall Inn brick buildings all act like a speaker when it comes to projecting sound down the street. “Does that have any effect on the noise issue, especially since there is a wall that projects that sound,” he asked.
Jacobs said the opera house board building is committed to its expansion plan, and thus is willing to do whatever is necessary to make it work. He assured the commission that the board would come up with a plan in writing that will outline how it will mitigate the sound issue to ensure compliance with the ordinance.
Heiser said the immediate goal is to mitigate the noise issue to the north of the property line, and that residences to the south will have a minor impact. If the opera house puts the “Cadillac” of chillers in, with appropriate sound buffers, the noise shouldn’t be a problem. However, he did not have an answer about whether the sound from the chillers will be amplified down the street.
“We can’t resolve this tonight but we express that we want the Cadillac version of the chiller and we want the opera house board to do whatever it takes to make sure that the noise level meets all criteria in all directions,” Everett said. “Really, the expansion issue, the city is in favor of donating the land to the east so they can expand their theater and put in an elevator and a chiller for keeping this awesome place cool for events.”
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