Last Fall, a contractor working for Google Fiber in Nashville, Tenn., made headlines for breaking a 36-inch water main while doing directional boring. That was the second time that contractor had broken a water main in a week. In a year of construction, fiber contractors in Nashville had caused damage to water mains between 71 and 82 times (accounts differ on the exact number). We’re not sure of the reason for all of them, but directional boring was involved in several of the incidents.
Breaking water mains is usually not too dangerous; however, two workers recently drowned in Boston when they hit a water main. Generally, it’s much more dangerous to work with buried high-pressure gas lines or electrical cables. In the Boston incident, rescuers were deterred by the presence of high-voltage electrical lines in the same area.
Wherever a contractor works—city, suburbs or country—digging or boring blindly can be dangerous. If something is broken, it will probably also be expensive, and the contractor will likely need to pay for the repair.
Obviously, learning what is underground before you dig is common sense. Back in 1964, Bell Telephone in upstate New York created the first call center where contractors could call to determine if underground cables were located in the areas where they planned to dig. By the 1970s, that evolved into AT&T’s JUNE (Joint Utility Notification for Excavators), and Congress created the Office of Pipeline Safety as well as regulations for pipeline safety.
Over the subsequent decades, the telecom, utility and pipeline groups cooperated under the umbrella of the Common Ground Alliance to create the One Call system, develop a manual of best practices and establish the “811” toll-free number for contractors to contact before digging. Now there is no excuse for not calling 811 a few days before digging to ensure you have the best data available about which utilities are in the area where you plan to dig.
But just calling 811 and getting information back from utilities does not mean you are no longer responsible for what happens when you dig. In practically every job, there are cables or pipelines that are not known or are not where they should be. I have talked to many contractors on this subject.
For example, one contractor was working on a rural fiber-to-the-home project. He always contacted the local One Call office and his friends at the local telco and utilities. After he had a few close calls with unexpected underground cables and pipes, he purchased an underground locator that used electromagnetic location, much like the devices treasure hunters use.
Electromagnetic, acoustic and radar methods can be used to locate underground cables and pipes. I recently read an article that included those along with one I did not expect: dowsing.
Dowsing is a technique for searching for underground water, minerals or anything invisible. A person carries an indicator (traditionally a forked stick) now often paired bent wires, pointed down toward whatever they are searching for. Supposedly, the rods dip, twitch or cross in response to unseen influences. I suggest you stick to the more modern, technical methods of searching for buried utilities.
The contractor I mention above uses an electromagnetic locator to search for underground utilities, and also does a manual dig before using the backhoe, trencher or directional borer. His crews just use a pick and shovel or manual post-hole digger to check for obstacles at various locations before they do the real digging or boring.
It seems that education is the major obstacle to reducing dig-ups or breaks. The One Call and 811 programs have helped reduce the dig-ups in the last decade by about two-thirds. But the 811 number is still only known to about half the population. With the massive growth in fiber installations nationwide, we have seen too many subcontractors and sub-subcontractors who simply don’t know that they need to plan a few days ahead and invest a little time to reduce their chances of causing a big problem.
Whatever you do, use the available resources before you start digging! Call 811 toll-free, or visit www.call811.com for more information. Another option is going to the National Fiber Optic Protection Summit conference run by the 811 group.
Also, the U.S. Department of Transportation’s National Pipeline Mapping System website enables users to search for buried pipelines. Visit www.npms.phmsa.dot.gov.