When Communications Services, Inc. (CSI) of Marshville, N.C., needs to run underground fiber optic line for telephone service to new housing developments, it relies on its air compressor to provide the power for all of its tools.
On a recent subdivision project, CSI's scope of work involved running over 3,000 feet of fiber optic cable through an underground conduit system that had already been installed. CSI used an Atlas Copco HardHat XAS 185 JD7 portable compressor to power the blow gun, which will blow a missile tied to a length of mule tape or string to the other end of the conduit. The mule tape is 2,500-pound test weight per square inch and will be used to pull the fiber optic cable back through the conduit.
The amount of air needed for the blow gun depends on the length and diameter of the pipe, and the number of turns or resistance. If the conduit is a mile long, for example, it would take two 185-cfm or a 350-cfm compressor.
"They're running fiber all the way to the houses now," says Travis Brown, a foreman for CSI. "Fire in the hole!" he laughs, alerting his team that the string is moving down the conduit.
Three men are needed to keep the string moving at the right speed and tension. One man holds the spool of mule tape, which spins around a rake handle. The next man makes sure that the tension is slack on the string in order for the third worker to feed the string through the conduit. The worker stringing the mule tape must ensure the tension is just right or the string could bunch up. It is a hard and tedious job; the string is heavy and the air is powerful.
When the missile is at the end of the conduit, it is time to pull it out, attach the fiber optic cable and begin the process of winching the string back through the conduit. Once the string has pulled the fiber back through the conduit, the fiber is ready to continue being strung above ground to the intended central station or node.
With a good team, the right tools - and the right compressor - CSI was able to smoothly pull the fiber optic cable through the underground conduit system. "The 185 is a good all-around machine," says Brown.