September 21, 2010 By Jessica Mulholland
Laying Cable in the Sewer
Though Rettie said i3's solution has been successful in the U.K. and Australia for the past eight years, there are some concerns about whether it will work for Quincy. One of the concerns is that last year, the city had approximately 52 breaks in both its water and sewer systems, Spring said. A break that occurred a few weeks ago closed a heavily traveled street for about four days. The city had to make the necessary repairs, place the underlayment and concrete overlayment, and then let it substantially dry before allowing heavy traffic back on the roadway.
"What'll happen is, if a street's closed off, that's OK with people," Spring said. "But if all of a sudden, they can't get their cable TV or can't get on the Internet with this high-speed fiber optic that the mayor has now presented them? ... Do you see what I'm getting [at]"
In addition, weather concerns also could derail the potential of a sewer-based FTTH deployment. "We're in a climate here where we have a lot of hot and cold variations during certain times of the year. It can be 15 degrees below zero here one day, and the next day it could be 55 to 60 degrees above," Spring said. "And with any component that's in the ground, whether water or sewer lines, the stress put upon them with the temperature change and the earth moving -- along with the heavily traveled streets -- it can cause problems."
But i3's Rettie said the pilot will be successful. "Damage to the sewer network can happen," he said, noting that i3 installs video cameras so it can see issues as they occur. Rettie also said the i3 method is different than how other companies or municipalities deploy fiber in the sewers. Other installations traditionally tack the fiber along the top of the sewer with stainless steel bands, he said. "If those stainless steel bands become dislodged, damaged or corroded, that fiber will drop down in the sewer," Rettie said, "and that has the potential to cause a blockage." The blockage is less a problem for the fiber-optic cable as it is for the sewer; because the fiber is hanging from above, Rettie said debris can get caught.
The i3 Group's solution deploys the fiber along the bottom of the sewer so it lies flat. In addition, the fiber is attached to the sewer at each manhole point using patented manifolds or mats and a special epoxy adhesive. "As you can imagine, a sewer is very dirty and wet, and not very hospitable, but the epoxy has been used within the oil industry, and it can actually set and adhere in the sewer environment," Rettie said.
Overall, Quincy is looking forward to this pilot and the potential it holds. Spring said he has city engineers and outside consultants working on the project, as well as people with fiber-optic experience. "We have a great team assembled; we're excited about this and hope it can become a reality for our community," he said. "I think overall it's going to be a really positive thing, but we have to get this pilot program started and take a look before we make any final decisions."
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