Panels to reduce noise in transit tunnel

The Port Authority will try an interim step to reduce the noise coming from fans it is using to reduce moisture in the Mt. Lebanon transit tunnel.

Authority spokesman Adam Brandolph said Monday that contactor Wellington Power Corp., which was hired for a 16-month project to replace the fans, will install baffles in fan rooms at the ends of the 3,000-foot tunnel in Dormont and Mt. Lebanon beginning next month. Residents who live on the Dormont end have been complaining about the noise since the authority began running the fans in late December.

Under ordinary circumstances, the authority only uses the one-speed fans for emergencies such as removing smoke from the tunnel. They operate at a low roar that makes it difficult to have a normal conversation a half block away.

After an inspection by the state Department of Transportation late last year found that moisture was corroding metal parts in the tunnel, the authority began running them regularly to reduce moisture.

Initially, the agency used the fans 12 hours a day as it tested how long they need to operate to keep the tunnel dry. That has been reduced to four hours at a time, 10 a.m. to 2 p.m. Monday, Wednesday and Friday on the Dormont end and Tuesday and Thursday on the Mt. Lebanon end.

The baffles, acoustical absorption panels, have been ordered and should be available in early August. They will be installed in fan rooms Mr. Brandolph described as “the size of a house” at each end of the tunnel.

The interim work is part of Wellington’s $5.1 million contract to replace the existing fans with multispeed fans to reduce the noise. The new fans aren’t expected to be installed until July 2022.