We are all familiar with the way new construction projects typically operate. First, we hear on the news that the road construction project will take nine months to complete and at a cost of eight million dollars. Then 14 months and 12 million dollars later, the project is still having problems.
There can be a variety of problems on any construction project but the number one cause of delays and increase in costs is from utilities. That gas main is four feet from where we thought it was, we were unaware of that communication manhole that was under a foot of gravel, and we thought that the only power lines were those aerial lines on the pole.
The problem does not begin with construction. It begins with the design engineers who have only poor information at their disposal. The utility prints are not updated, or they are wrong, or there is a utility line no one even knew about. The problems all come to light during construction, but they begin with poor information at the beginning of the project, during the design process.
The California High Speed Rail project is an excellent example of this. This was to be a 2-track system slated to run from Los Angeles to San Francisco by 2020 and at a cost of 33 billion. Instead, it has been dropped down to a one-track system, a projected cost of at least 100 billion, and the completion date is now somewhere between the year 2028 and infinity, and right now it looks much closer to infinity.
The problem can be summed up in three letters – S.U.E – because the California DOT did not use it on the project.
Subsurface Utility Engineering (SUE) had its origins in Virginia in the 1980’s. The purpose of SUE was to remove all of those surprises from highway projects. The basic idea is for the local DOT to hire an engineering firm to gather massive amounts of information on the project area, all of it relating to utility data. Don’t trust old outdated utility prints, don’t trust old utility marks, don’t trust anyone’s recollections of what is in the ground, frankly – don’t trust – investigate it yourself.
SUE projects are conducted by civil engineering firms, and obligated to abide by American Society of Civil Engineers (ASCE) document 38-02. They are required to use any and all of the latest geophysical instruments and practices to find every single type of utility in the ground, no matter who owns it, or whether or not it is indicated on the utility prints correctly. If it is there, then find it, mark it, map it, and relay that information to the design engineers.
This includes not only electric power, gas, water, and the usual, but also sanitary sewer and storm sewer. There are some disagreements on many areas that have not been specifically spelled out by ASCE 38-02. This includes traffic systems and irrigation systems, though most SUE firms do not map sprinklers.
The center point of SUE projects is on the Quality Levels. This is the real bedrock of any SUE project. Not only does each utility line need to be mapped, but each and every utility line must be labeled as to its Quality Level to indicate how much confidence the design engineers can put into designing around over or under each line. In some cases, a utility may simply need to be moved to make way for the change in the road and new changes to the drainage system, but the importance of SUE is to know for certain that the utility must be moved instead of assuming that it must be moved because of how it is indicated on the utility prints. If the pipe is four feet off the curb then it needs to be moved and at a lot of cost. But if it is four and a half feet off the curb then there will be just enough room to leave the pipe in place. So, the question is this – how do you know the pipe is four feet off the curb?
There are 4 Quality Levels to answer these questions: Quality Level A, B, C, and D. QLD indicates that the position of the utility line is vague coming only from old records or recollections.
QLC indicates a utility line where both ends of the utility are known, and that the utility should be running straight. This is most common with storm and sanitary pipes between manholes or other drainage structures.
QLB is the most common, and indicates a utility line that has been traced out (designated) with an acceptable electronic geophysical instrument. This is most commonly a Pipe & Cable Locator, but may be Ground Penetrating Radar (GPR), a magnetometer, a P&C Locator used in conjunction with a rodder, a pipe inspection camera, a gradiometer, a sonde, or many other possibilities.