Since the new fan was installed, we have been measuring sound levels from the property line and at a neighboring home. When we ordered the fan, we were told the new fan would have a blade passage tone of 23 dB lower than the previous fan. It’s measuring just 7 dB lower. Obviously, this is another major disappointment.
We have since been in contact with the Director of Engineering at Twin City Fans (the fan manufacturer), as well as the fan rep, who has visited the mill and performed some additional testing.
At this point, we’re working on several additional solutions:
1. Reducing the wheel size in the fan housing: The fan manufacturer has evidence from another project showing that by doing this, it could reduce the sound level of the tone by up to 10dB. This would be an improvement, but it may not completely solve the problem.
2. Replacing the silencers. We are now working with four additional engineering and manufacturing firms regarding better-suited silencer designs. We are in the process of receiving conceptual designs and proposals from them and hope to have a final decision in the next few weeks.
Unfortunately, there is no simple solution to this problem. We will continue to keep the fan in pilot mode in the evenings and on weekends and run at a reduced level during the day until this issue is solved.