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High-tech, below grade.

High-Tech, Below Grade

Much of a property manager's work is problem-solving, and it takes more knowledge to solve some of the problems we are now confronted with, given the ever-increasing complexity of buildings, government regulations, and a law system that seems constantly in flux.

While our ability to solve office problems has been enhanced tremendously, due to growing reliance on sophisticated computer hardware and software, advances in field operations have been slower in coming. Nevertheless, new field-oriented technologies are emerging which are giving property managers a much-needed boost in their ability to resolve problems far more quickly and cost effectively.

For as long as I can remember, two of the worst field problems have occurred underground with broken sewer and water lines. Because it is impossible to know where the problem is occurring, you must move forward or downward based on a best guess. But even the best guess is often wrong, making it necessary to guess again. And again.

Somewhat ironically, the least expensive element of such trial and error is the cost of the line repair itself, about $300 to $400, compared to the $15,000 or more to close the holes properly and install a new surface, be it sod or asphalt. However, new technology is now available. While it will not eliminate the need for dig-ups, it can at least help eliminate the need for trial and error, as well as the cost of repairing the damage done while waiting for the problem to make itself more obvious.

For sewer problems, this new technology involves the use of cameras that permit a real-time visual analysis of conditions. For water line leaks, the technology is computer-based hydroacoustics, used to determine where lines are, whether or not they are leaking and, if so, where.

Sewer line analysis

Television inspection systems are comprised of a camera, a camera-control module, a cathode ray tube (CRT) monitor and a distance indicator/captioning unit, useful in making videotapes of inspections. The television camera, just 8 inches long with a 1 1/2-inch diameter at its widest point, is mounted on a skid that is pulled or pushed through the line.

A variety of accessories are available, enabling the camera to be outfitted on-site to match the service required. For example, one camera head has a mounted ring of lights; another, used for wet work, encloses the lens in a water-tight, glass-covered case to which a light is attached. Although the camera is small, the quality of its resolution is outstanding.

A primary concern to our company was practical application of this new technology. We had one particular problem unit in mind: A basement unit in a low-income project had been allowed to stand vacant for approximately four years because the four-inch drain installed in the concrete slab had a history of backing up, depositing as much as a foot of water and raw sewage in the apartment. Site personnel told me they had repeatedly had the lines snaked out, but to no avail. Within a week or so the problem would repeat itself.

It was estimated that as much as $50,000 would have to be spent to dig out the line, possibly replace it, restore the basement floor inside, and repair asphalt surfaces outside. It was more cost effective just to leave the unit vacant. Had new technology not been available, they would have been right.

The inspection of the line revealed in minutes the problem which had caused four years of head scratching. Approximately 62 feet from the drain's opening in the basement floor - beneath a city street - a sewer pipe was broken completely in two.

The point of the break was marked on the asphalt and the appropriate officials were called. They made the necessary repairs the following day at no cost to the project owner. The problem had been located, repaired, and resolved in a relatively short period of time without costly, messy random inspection.

A similar problem existed at an office building which, since its construction, experienced intermittent flooding at the lobby level. Since the camera could not be pulled through the drain line, it was mounted on its skid, which, in turn, was mounted on a fiberglass push rod.

The line was filled with debris, however, and this made the camera ineffective. Accordingly, the crew installed a manhole and then brought in its high-pressure cleaning equipment and sent the camera and its skid - still mounted on the push rod - down the line, about one foot ahead of the jet nozzle.

Water was pumped at very low pressures until the camera revealed the blockage, about 80 feet from the new manhole. The nozzle was withdrawn and the camera was pulled back about one foot revealing a broken sewer joint that had been left there since day one. The sewer was excavated at this point and repaired. A final video inspection revealed that the problem was gone for good.

Water line leak

detection and location

The trial and error associated with water line leakage can be more costly than that associated with sewer line problems. When a water line rupture first occurs it often will continue unnoticed for some time.

The cost of water loss is not significant at first, but can mount over time. Far more costly is the damage which the leak can cause, particularly when it is under a parking lot or access road.

As the water seeps from the line break, it begins eroding the asphalt structure's subbase. If vehicle loads do not cause depressions in the asphalt surface at first, they will eventually. This typically occurs after the spring thaw. The cracking that occurs will usually permit the entry of run-off, leading to even more subbase damage. Water will bubble to the surface, almost never above the actual site of line rupture.

There seldom is an alternative to digging where it is most obvious. If the line problem is not found there, more digging is necessary until the location of the break is determined. But at what expense? A plumbing crew has to be at the ready; a backhoe or front-end loader is needed to dig the pits; a dump truck is needed to haul off the mud; dump fees must be paid; shoring often is required to provide safety while the crew repairs the line; new fill must be brought in and tested for organics; the fill then has to be compacted and tested to assure conformance with specs; the new asphalt must be installed; and new striping must be performed.

Again, the cost of actually repairing the line may be less than $500. But the cost of the dig-up and attendant surface and subsurface restoration can be 30 times that or more if you do not know where the problem is located.

A computer-based hydroacoustic system can aid in the detection of a leak. The three basic components of the system include a radio detection unit (RDU), a leak detection unit (LDU), and a leak location unit (LLU). Their application is illustrated through a case history affecting a 180-unit moderate-income building that had an unusually high water consumption rate. Since no other explanation could be found, we were convinced a leak had to exist.

We went to the basement where a radio transmitter was attached to the pipe. Outside, a technician held a metal-detector device tuned to eliminate any spurious signals. Every 10 feet or so, he stopped to extend the single-line diagram he was making. Within two hours, he had located what we assumed to be the entire underground network.

The next step took us back to the basement. This time the leak detection unit (LDU) was employed by clamping a transducer to a valve. The transducer's output is fed to the LDU, which amplifies the sounds and filters out all wavelengths except those associated with water under pressure being forced from a line through a rupture. Something was heard, indicating there was a leak about 40 feet away.

The valve cover was opened and a metal rod was put through the opening to the valve. This time the leak signal was much stronger. The procedure was duplicated at the next valve opening, and signal strength indicated the leak existed on the line between the first and second valve.

The next piece of equipment used was the leak location unit (LLU), a computer used as a correlator. Inputs came from two LDUs, one attached to the first valve and the other attached to the second. A signal was sent from one to the other to determine the time required to travel between the two points. This indicated the distance from either valve. Once that was known, it was easy to estimate the exact location of the leak. In this instance, the crew was within three feet.

The cost of the service amounted to $450. The cost of the excavation repair was just over $3,000. If trial and error had been necessary, chances are the leak would not have become visible for another three months. In the interim the cost of wasted water would have been approximately $750. The subsurface damage it would have caused would have been far more substantial, and correcting it - along with the cost of making and restoring several holes - probably would have amounted to an additional $6,000.

Taking advantage

of new technology

The equipment required to perform sewer inspections and water line leak detection and location is expensive and not usually used on a regular basis. As such, it is not cost effective for even a major property management company to invest in it, except through a separate operating subsidiary that would service other companies too.

The water line equipment in particular is subject to error, so some type of guarantee is essential. Most sewer-TV inspection organizations are fair in this regard, imposing no charge if the leak location they find is not "reasonably close" to the actual location. Reasonably close should be defined before any work is done and should be based on factors unique to the project. In our case, with approximately 350 linear feet of four-inch and six-inch line, reasonably close was defined as "within four feet." The guarantee does not apply when it is not known that a leak exists and cannot be found.

When working with owners during the acquisition of a property, advise them that they can avoid the possibility of a major water and/or sewer line repair bill by having lines thoroughly surveyed before making the purchase.

Monitor water consumption at all properties by reviewing billing records for each meter. Establish typical usage patterns for each meter that reflects the different sizes of the residential units on the meter, as well as varying types and sizes of commercial occupancies.

As soon as consumption exceeds the levels established for each meter, determine the cause. If the source cannot be located (leaking faucets, nonfunctioning diverters, running toilets), then an underground leak exists. You should call for leak detection immediately.

Preventive maintenance of sewer lines calls for their regular cleaning. Preventive maintenance of water lines is now a possibility, by surveying for leaks on an annual basis, typically in mid-spring. The initial survey should include line location and preparation of as-built. Thereafter, leak detection alone is needed. The cost of the service is low, typically $450 for a 250-unit garden complex or high-rise. Regular monitoring of meters should make annual line surveys unnecessary.

H. Jace Greene, III, CPM[R], is vice president of Edgewood Management, a division of Mid-City Financial Corporation, a Bethesda, Maryland, firm specializing in the management of real estate. He is past president (1974) of the Greater Atlanta Chapter of the Institute of Real Estate Management and recipient of its Property Manager of the Year Award. He is also past president of the Property Management Association of Metropolitan Washington (D.C.)

PHOTO : A video monitor attached to a control cable allows easier above-ground inspections of pipes.

PHOTO : A miniature camera, equipped with a lighting attachment, permits inspection of pipes up to 18 inches in diameter on either a horizontal or vertical plane.
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Title Annotation:using high technology means to solve problems associated with sewer and water lines
Author:Greene, H. Jace
Publication:Journal of Property Management
Date:Sep 1, 1989
Words:2016
Previous Article:Preventing plumbing disasters.
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