ORIGINAL REPORT, 9:15 AM: After starting the day with an inbox full of reports regarding the recurring noise that’s come to be known as “The Hum,” we’ve been checking around. You’ll recall that the last time this happened, the distinctive sound was traced to vacuum-type equipment from an offloading operation at the CalPortland terminal on the Duwamish River, and as reported here last week, they have been working on figuring out ways to muffle it. Is this the same sound? Hard to tell. Our early watch headed in that direction and couldn’t determine conclusively. We checked with Highland Park Action Committee leadership, which has been in frequent contact with CalPortland; they say management e-mailed them over the weekend to say said they have placed more noise blankets around the machine while awaiting a new muffler, and they are working on more interim measures. We have an inquiry out to them too to see if there’s even an offloading operation currently under way. So no conclusions, but wanted to let you know we’re checking on it. The city remains your official contact for noise concerns – find info on that here.
1:08 PM UPDATE: From Pete Stoltz at CalPortland, one of the people we met with at the facility last week along with HPAC leadership:
We are in the process of offloading a vessel that arrived at our Cement Terminal on Saturday Morning October 20th. The schedule for offloading is weather dependent because we cannot offload when it is raining. This ship requires about 84 more hours of offloading operations. We currently predict offloading will be complete on October 25th, weather permitting.
We have been monitoring the posts on the West Seattle blog and read the latest posts from your readers regarding the noise this morning. We recognize their concerns and take them seriously. We also understand that recent noise measurements showing that the equipment technically complies with noise code requirements does not resolve those concerns. That is why we have continued our effort to muffle the noise from the machine since we first learned it might be the source of the “hum” on September 26th.
As you reported in your recent update we replaced one of the two silencers on the machine and ordered a replacement for the second silencer. Unfortunately, the new silencer has to be custom made for the machine, but it is on order and scheduled to arrive and be installed before the next ship arrives for offloading during the first week of December. Due to the physical properties of noise, our noise consultant expects that installation of the second silencer should result in a more substantial reduction in noise than can be achieved with replacement of only one silencer.
In addition to the installation of the new silencer, we fashioned an additional baffle and attached it to the air discharge port and wrapped the old silencer in sound blankets. We also installed additional sound proofing material on other parts of the machine. On Saturday, the crew constructed and installed additional panels around the silencers made of plywood and foam insulation (photo attached), and are continuing to construct and install additional panels in an effort to enclose that area of the machine in an effort to improve the situation.
We appreciate our neighbors’ patience and recognize and understand the frustration expressed in the comments on the blog. We are continuing to take steps to reduce the noise from the machine, both short- and long-term, and will continue to provide additional updates on the status of our progress on this effort.