If you suddenly find yourself without an Internet connection, there’s a good chance that somewhere a team of construction workers just uttered a collective “uh-oh” because their backhoe dug up a telecom cable. Oops. It turns out that this problem is so common that it is costing millions upon millions of dollars in repairs every year. Backhoes, drilling and digging are serious cable killers. A SMALL EXAMPLE TO START: SWEDEN In Sweden, admittedly quite a small country, around 8,000 telecom cables are cut off by backhoes every year. In fact, a construction crew managed to do this very thing not far from the Pingdom office a few months ago. The repair costs alone for these accidents are roughly $30 or so million per year in Sweden (an estimate from a recent Computer Sweden article). If we have that many incidents in a small country like Sweden, how common are they in a big country like the United States? Let’s have a look. THE US BILLION-DOLLAR FAIL Finding recent exact data for the US proved to be tricky. A Wired article from 2006 gave us some numbers to start with. In 2004, there were 675,000 excavation incidents where cables and pipes of various kinds were damaged in the US (often referred to as “underground utility damages”). More than a quarter of those, 27.5%, were telecom-related. That would mean 185,625 cases where US telecom cables were damaged in 2004. If the cost of repairing a cable is similar in Sweden and the US, telecom cable repairs may have been around $700 million in 2004. However, there are reports that things have improved. In 2007 there were an estimated 256,000 underground utility damages in the US, a lot less than in 2004. If a quarter of those were telecom-related, that leaves us with around 64,000 incidents where underground telecom cables were damaged. Even after such a big improvement, the yearly repair costs still end up in the hundreds of millions of dollars. Over a longer period of time, say 5-10 years, the repair costs will count in the billions. AND WHAT ABOUT WORLDWIDE? We have just looked at Sweden and the US here. Now imagine the costs worldwide. Those will easily amount to several billions of dollars and hundreds of thousands of telecom cable breaks due to our careless digging. Every year. And a ton of downtime for various networks, we suspect. PREVENTIVE MEASURES In the US there is a project called One Call where both companies and individuals can call in to find out what cabling exists where they are planning to dig. An interesting option has been explored in Denmark, where a central, nationwide website provides information about the underground cabling that exists in various areas. This website can be consulted by people and companies preparing an excavation. This has cut (no pun intended) the number of accidents by 70% which is a huge improvement. Sweden has just launched a similar initiative, so we’ll see if it works as well here. Now we just hope that that the operator of that huge backhoe that recently drove by doesn’t get any funny ideas… this is article is from http://royal.pingdom.com/
Utility Locating and Marking Best Practices
2.14 Sub Surface Utility Engineering Best Practice Statement: When applied properly during the design phase, Subsurface Utility Engineering (SUE) provides significant cost and damage-avoidance benefits and the opportunity to correct inaccuracies in existing facility records.1 - See more at: http://commongroundalliance.com/best-practices/best-practices-guide/214-subsurface-utility-engineering-sue#sthash.pHrgTCys.dpuf Practice Description: In certain cases and environments, it may be difficult or impossible to determine the locations of all utilities and/or impediments with sufficient accuracy to avoid damage or delay during construction. In these cases, SUE is applied during the design phase to locate, identify, and characterize all existing utility infrastructure (and other relevant nonutility features) found within a given project/area. SUE is applied in a structured manner in accordance with practices and quality levels found in ASCE 38-02 “Standard Guideline for the Collection and Depiction of Existing Subsurface Utility Data.” The project owner dictates the required quality levels as well as the amount of effort expended by the SUE provider on each. Although the standard is more detailed and comprehensive, the following is a brief summary of the quality levels defined therein: QL-D involves utility records research and interviews with knowledgeable utility personnel. QL-C involves surface survey and identifying and recording aboveground features of subsurface utilities, such as manholes, valves, and hydrants. QL-B involves application of “surface geophysical methods,” such as EM-based locating instruments, GPR, radar tomography, metal detectors, and optical instruments, to gather and record approximate horizontal (and, in some cases, vertical) positional data. QL-A involves physical exposure via “SOFT-DIGGING” (VACUUM EXCAVATION or hand-digging) and provides precise horizontal and vertical positional data. SUE results are integrated into the design process, in which design engineers use the information to create construction plans that accommodate existing infrastructure, thereby reducing the overall risk of conflicts and/or damage.2 - See more at: http://commongroundalliance.com/best-practices/best-practices-guide/214-subsurface-utility-engineering-sue#sthash.pHrgTCys.dpuf References: U.S. Department of Transportation—FHWA (12/1999). Cost Savings on rojects Utilizing Subsurface Utility Engineering. Pub. No. FHWA-IF-00-014 U.S. Department of Transportation—FHWA (3/2001). Subsurface Utility Engineering: Enhancing Construction Activities. Pub. No. FHWA-IF-01-011 ASCE 38-02 Standard Guideline for the Collection and Depiction of Existing Subsurface Utility Data Pennsylvania state law - See more at: http://commongroundalliance.com/best-practices/best-practices-guide/214-subsurface-utility-engineering-sue#sthash.pHrgTCys.dpuf 1. TR-2007-02: Modification to statement approved by the CGA Board on August 24, 2007 2. TR-2004-03: Amendment approved by the CGA Board on March 4, 2005 - See more at: http://commongroundalliance.com/best-practices/best-practices-guide/214-subsurface-utility-engineering-sue#sthash.pHrgTCys.dpuf US Utility Potholing & Air Excavation uses provides quality level A and quality level B Sub Surface Utility Data.
Potholing saves time and money.
Portable vacuum excavators have been a regular sight on job sites for years. These unique units were originally used to clean septic tanks and car wash pits and to remove slurry from horizontal directional drilling projects. Now contractors are discovering that these machines have a wide range of uses on the job site, from potholing for utilities to cleaning valve boxes. By Greg Ehm Construction Equipment News Letter http://www.constructionequipment.com/potholing-utilities-saves-time-and-money July 28, 2008 Portable vacuum excavators have been a regular sight on job sites for years. These unique units were originally used to clean septic tanks and car wash pits and to remove slurry from horizontal directional drilling projects. Now contractors are discovering that these machines have a wide range of uses on the job site, from potholing for utilities to cleaning valve boxes. Vacuum excavators are self-contained units that use pressurized air or water to displace soil and create a dry or wet spoil. The displaced dry or wet spoil is removed from the area through a hose using high-velocity suction and stored in a holding tank on the vacuum. Vacuum excavators can be mounted to a trailer or the back of a truck and range in size from 100 to 1,200 gallons of capacity. Since vacuum excavators use low-pressure air or water to remove spoil, they are perfect for potholing or identifying existing utilities during underground construction projects. "Damaging existing utilities can be costly in terms of project downtime and potential contractor fines," says Dave Gasmovic, president of McLaughlin Boring Systems in Greenville, S.C. "The low-pressure water and air will not damage existing utilities like a backhoe, compact excavator or shovel. In fact, the air and water move around the existing utilities, giving the operator a clear view." Operators can select the amount of air or water pressure appropriate for the utility. A lower pressure of 1,500 psi should be used for gas and fiber lines in order to not damage the line coating. A higher pressure can be used for water lines. Line Exposure While locators are becoming more accurate, it's still important to see exactly where the line or pipe is located. Contractors are not allowed to dig in the safe zone, which may be from 18 inches up to 3 feet from either side of the marked line. The required distance varies by state. Contractors are only allowed to dig by hand or use a non-destructive method like vacuum excavators in the safe zone. Using a vacuum excavator instead of a shovel has advantages. A shovel against a water pipe is non-destructive, but on a fiber optic line a shovel can be as destructive as a backhoe, especially in hard ground conditions. "A lot of cable has been installed using horizontal directional drills (HDD) rather than trenchers, so you don't have the old-fashioned ditch line like in the past," says Gasmovic. When lines are installed using a trencher or backhoe, a lighter material like sand is placed around the line. As a contractor digs, the ground gets softer. This indicates the line is in close proximity. Lines installed using HDD don't disturb the ground or leave a ditch line, so the ground is the same hardness and it is difficult to know if you are getting close to the line or cable. Since the ground may be hard, you can easily cut a cable line with a shovel. Using a vacuum with air or water at a non-damaging pressure will safely expose the line. Selecting The Right Unit Vacuum excavators come in all sizes and options, so it's important to select a unit that will best fit your intended use. Water-based units typically dig faster through a wide variety of spoil types and reduce the volume of the excavated material. These units move more displaced wet spoil into a holding tank than an air system. However, the displaced spoil is wet and cannot be returned to the site immediately without drying. While spoil from air systems can be directly returned to the site, these systems do not cut as well in hard ground conditions, such as clay. "I encourage contractors to look for a unit with a good-quality vacuum blower, the heart of the vacuum," say Gasmovic. "They should also select a tank that has the capacity to hold a half-day's or day's worth of spoil. This will reduce the number of trips you need to make to dump the holding tank." If you are working in areas with cobble rock, then a unit with a 4-inch hose and 1,025-cfm blower unit will be more productive. Cobble soils will require a larger blower to effectively remove the spoil. The larger diameter of 4-inch hose will help reduce the potential for clogging. In areas without rocks, a 575-cfm system and 3-inch hose will suffice. The blower size also affects the amount of engine power required — a larger blower will increase the cost of the unit. Gasmovic recommends that contractors pay special attention to the filtration system and select a system that will filter the spoil and avoid clogging. Finally, be sure to select a strong trailer frame that will support the weight of the unit and a full tank of spoil. There are a number of options available: controls that allow the contractor to reverse the flow of the vacuum to blow the spoil back into the hole; booms that support the weight of the hose, placing less effort on the operator; combo units that include a jetter to clean sewers and remove the resulting trash; and automatic tank clean-out systems and auxiliary hydraulic systems that allow the contractor to run a concrete saw or breaker off the unit. The Payoff Taking the extra steps to pothole may seem like an added expense or more time, but Gasmovic stresses that safety is important. "Hitting a gas line with a backhoe, trencher or HDD could be catastrophic. A water line hit could put a hospital out of business," says Gasmovic. "The cost of shutting down a project for a day is sure to exceed the cost for a $3,000 locator and a little extra time." In this photo Chris is starting a Pothole to verify existing utilities with the use of air / vacuum excavation. This is an example of our employee Mario digging a utility test hole or utility pothole to collect Sub Surface Engineering Data using air vacuum excavation method. We collect SUE Data through these methods at US Utility Potholing & Air Excavation.