The last thing any customer wants to do to existing buildings and infrastructure is to rig and dig, break concrete and sidewalks and then cut the asphalt. The costs are higher, it takes longer and it can be a frustrating process. The end goal was to unify the campus and provide a fiber backbone network, removing individual services at three separate buildings, and to provide one campus network.
One of the things we do before we issue material orders and commit schedules is to do test pulls of underground conduit. We did a pull test of strings between two buildings with no problems. Then, we taped off the end of a metal fish tape and did a short test run to "fish" or push the metal tape through the occupied flexible duct inside underground conduit towards a third building. We easily pushed the tape through 13 feet and then removed the fish tape and found it wet, and that is a warning sign of what may be ahead.
The 2-inch flexible duct contains an existing almost half inch diameter 50-pair PVC Telco cable that was likely installed with the building. The conduit is cracked where it penetrates the concrete floor and the 50-pair cable is live and connects telephone extensions campus wide including fax, alarm and DSL lines. In my last post (Inspecting) I stressed the importance of site inspections or site surveys as we call them. Have a look at the photo at the top of the next page:
As an electrician buddy of mine would say, "What’s wrong with this picture?"
First the can--the gray metal box on the wall houses all the Telco feeder cable and other customer premise terminations. There are terminations with gear connecting to a cellular tower on my customer's campus located behind a fourth building. There is no cover on the can. Think I’m nitpicking? Ever wonder why cell calls drop?
Notice the small amount of trash inside the can--electrical tape and paper. There are wires and cables that run outside the can preventing a cover from being attached. There's also an abandoned patch cable just hanging. The steel flex duct in the background feeds services to and from the cellular tower. The black flex duct in the foreground contains the 50-pair PVC Telco cable. The black flex duct feeds into an underground conduit to another building 175 feet away--the same conduit that we ran a fish tape through at the other end and found it wet at 13 feet. Again, what's wrong with this picture? PVC cable is an indoor cable not intended for underground and outdoor use. Of course it will work and it may keep working for years in spite of water and any attempts to pull a fiber cable through the same flex duct alongside the existing 50-pair.
So what do we do? We brought in our electrician contractors with their Greenlee vacuum/blower power-fishing unit. (See photo below--look carefully!) After 30 minutes we removed about 7 gallons of water at this building that is on a lower grade than the building the conduit connects. The water was dirty but clear and no suction could be felt at the other end. We moved the vacuum unit to the far end (higher elevation). After another 30 minutes we removed about a half-gallon of dirty red clay-colored water. Next we moved back to the lower elevation building and attempted to create suction and still could not get positive airflow from the far end. Once again we tried both ends. These are not positive indicators for any continuous buried conduit--is it continuous? Is there a break, or a junction box buried in the ground? The conduits should run line-of-sight with minimal sweeps between the two points. No one knows. The Greenlee tool also serves as a blower to push a string with a small dart through the pipe in a matter of minutes or even less depending upon airflow, obstructions and sweeps.
Next we used a half-inch conduit rodder in an attempt to push from either end to the other building to pass any initial obstructions. This proved unsuccessful and too big of a rodder to maneuver. A conduit rodder is a continuous fiberglass rod and looks like a big fish tape on wheels or a stand.
What are our options? (Lowest to highest cost)
* Use a conduit rodder designed for 2-4" conduit
* Cut the 50-pair and tie it off to a rope and use the 50-pair as a pull string to put in a rope and a new 50-pair cable (High Risk--remember the red clay colored water)
* Install aerial cable/fiber (Unlikely to get Board or county approval)
* Mole from grass to grass of each building then trench remaining ends to each building foundation to install new conduit/fiber
* Rig & Dig and get ready to break concrete and dig up the ground, sidewalks and asphalt private roadway
The obstacle is 175 feet of buried conduit hindering us in moving forward to implement some of the cool stuff that folks talk about here each week. Five years ago when we first visited this site, the folks that maintain the campus commented to us about "circuits that keeping tripping on the main panel." While this is a technology venture, it's related. Look carefully at the last picture, below. Since Hurricane Irene, we’ve had more rain and lots of it. In future posts maybe you'll get a taste of what happens when you go on the road with Matt.
