Working with Occupied Duct Systems:
IHC Construction Companies, LLC Blows Away The Problems
As any contractor knows all too well, problems on the job site occur all the time. Sometimes you expect them; sometimes it’s a surprise. Either way problems or challenges need to be dealt with in an effective and efficient manner. Whether it’s brute force or innovative technology that solves the problem, utility contractors are renowned for finding solutions.
Recently on a project for AT&T in Huntley, Ill., Larry Creadon, project manager IHC Construction Companies, LLC Elgin, Ill., was faced with one of those situations. IHC was contracted to furnish and install a cable pulling or placement mechanism, into the existing occupied conduit system for the Huntley School District. Once the pulling mechanism was in place, a mesh ductwork would be pulled in to house fiber optic cable for dedicated district services. Installing the pulling mechanism (pull-tape) proved to be the tricky part.
Creadon said, “Total footage for this project was approximately 6000 feet, divided between seven or eight sections. Once the pull-measuring tape is installed properly, placement of AT&T specified and approved product would follow. That product is Maxcell, a mesh-type duct product. However, after spending long hours on this particular project trying to duct rod the existing conduit without success, we needed to find a different method, a solution to our problem.”
IHC Construction Companies, LLC was contracted to install a mesh duct product into an occupied duct system for the Huntley, Ill. school district. When traditional duct rodding proved ineffective, crews turned to a universal split winch line blower to place the pull-tape.
With the help of Utility Sales Associates (USA), Lake in the Hills, Ill., and Condux International, Mankato, Minn., Creadon was able to find that solution.
Skilled Teams
IHC Construction Companies, LLC is a full-service construction contractor with roots that go back over 100 years. According to IHC’s web site, the company was started in 1906. Initially the company manufactured concrete blocks compressed by hydraulic pressure. Concrete blocks were phased out beginning in 1913 when road paving became their primary business. As time progressed, the company accelerated their commercial, industrial and institutional building programs. Today the company is diversified and offers a wide range of services including general contracting, construction management, design and build, and underground utility construction.
Utility Sales Associates was started in 1991. Its territory includes the states of Illinois, Wisconsin, Indiana, Michigan, Ohio, Missouri and Kansas and is covered by eight salespeople throughout the Midwest and five inside personnel. The company focuses on providing equipment options for the power utility and telecommunications markets including utility line construction, outside plant and damage prevention safety products.
According to USA Product Manager Steve Cohen, the company is about helping clients find answers. He said, “Our goal is to provide solutions to existing problems at the end-user level. And that’s what we were asked to do on this project. Find a solution for placing a pull mechanism in occupied duct.”
Occupied Duct
When faced with the choice of trying to utilize existing duct work or install new to accommodate additional fiber optic cable, many providers are choosing to stick with what they have and get more capacity out of existing conduit systems.
Creadon said, “The ability to maximize the open capacity in an existing occupied conduit allows for a substantial savings, to a network provider, based on the alleviation for new conduit and innerduct placement via either open trench or directional bore methods.”
However, installs into occupied innerduct can be challenging and a host of problems can occur, especially in longer runs. Creadon explained, “500 feet and over seems to change how successful working in an existing occupied conduit will be. Traditional means of working in occupied conduits might result in hours of duct rodding without any success in placing material properly. If the pulling mechanism becomes wrapped around the existing cable, it creates a problem for the successful placement of mesh duct and ultimately the cable. If materials are not placed properly it could result in very long and frustrating hours and lost revenue for a contractor.”
On the Job
In order to create the additional pathways for cable placement that the district required, IHC crews needed to install a mesh duct. The existing fiber cable, however, could not be taken out of service. The run lengths between manholes and splice boxes were longer than 500 feet, which posed a challenge because of the probability of the material over-wrapping the existing fiber. Without the ability to break into the duct run somewhere in the middle and rod-out each way, IHC crews had a difficult time with traditional rodding methods and decided to pursue a different technique with the assistance of Utility Sales Associates.
Cohen said, “I was asked to provide the most field-efficient method, or market solution, for the placement of a pulling mechanism into an occupied duct. In this case I thought blowing the pull-tape in place might work best. I visited the job site, along with IHC, to obtain the existing cable outside-diameter to ensure that we had the proper accessories and to verify conduit integrity for air pressure prior to mobilizing crews. I was also on the job site, the day of installation, to explain how the blowing tool works and primarily to verify if there were any problems and, if so, what they were.”
Creadon said, “After losing numerous hours of production, from exhausting traditional field methods, the winch line blower provided IHC and AT&T a solution that alleviated the reported field problems and frustrations."
Prior to setting up the winch line blower to blow in the pull-tape, crews used it to clear water out of the existing conduit.
Winch Line Blowing
Using compressed air to install a product into an innerduct is a simple process. Condux International Product Manager Eric Cope explained, “A winch line blower is designed to install winch line into HDPE and PVC duct systems using compressed air. More advanced units can also install rope and measuring and pull tape. This type of system incorporates interchangeable adapters and various sized venturis with one body, allowing the blower to adapt to a range of conduit sizes and products.”
For the Huntley project, IHC crews used a Condux split winch line blower and a 185 CFM air compressor operating between 120 and 125 PSI. Crews selected the appropriate adapters and venturi configurations for the particular project. Before setting up the winch line blower to blow in the pull-tape, crews used it to clear water out of the existing conduit. Once the conduit was clear, crews assembled the split winch line blower. An inflatable, spring-loaded birdie was used on the front end of the tape to capture as much air as possible to help aid in the placement of the pull tape.
Results
IHC crews were able to successfully clear the innerducts of water and install the pull tape without incident. Average runs took 45 minutes from start to finish. That included setup, water clearing, re-setup and tape installation. According to Creadon, blowing in the pull-tape helped them stay on schedule. He said, “The tool allowed for us to make up lost time and still meet our deadline date for the installation of the mesh duct. The occupied blowing concept has been around in the industry for years. This unit is a very field friendly tool. From its size to ease of set-up from beginning to end, it was a solution we look forward to incorporating into our portfolio of expertise.”
“Nothing is ever 100% effective in the construction world but the winch line blower allowed for us to make up the lost time in order to meet our project deadlines. From initial set-up to blow water out of the system and convert the unit to blow in, the pulling mechanism was quick and efficient. The winch line blower provided us an option to accomplish the overall project objective in an efficient manner.”
