Penetrating Vision

A South Carolina contractor tackles tough pipe investigations with a cutting-edge portfolio of video, laser, sonar and mapping technologies

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A water and sewer utility in the southeastern United States faced the prospect of spending $42 million to replace a 4,800-foot 28-inch steel force main that had been malfunctioning for three years.

Believing there must be a better way, the agency’s engineering consultants brought in AET Robotics & Inspection Services to diagnose the trouble. Using a special float rig with CCTV cameras and laser and sonar profiling, AET, based in Clemson, S.C., inspected the pipe from end to end as it ran 75 percent full of wastewater.


The investigation found the problem: a contractor using horizontal directional drilling (HDD) had bored clear through the pipe and installed a 6-inch sewer lateral that obstructed the flow. The utility ended up repairing a 14-foot section of the force main at a cost of $80,000 – which it ultimately recovered from the HDD contractor.


That’s the kind of value AET can deliver with its complete array of pipe inspection technologies. The company, based in Clemson, S.C., solves tough problems for water and wastewater utilities, municipalities, and diverse industrial customers.


With a core group of 12 employees who are experts in their fields, the company reaches out across North America and sometimes overseas. The AET team members oversee projects and contract locally for the equipment and labor they need.


Ideal background

Company founder Mike Mraovich came to the business with extensive experience and multiple certifications in environmental services and hazardous materials. He became an EPA Certified Hazardous Materials Instructor and later worked in positions of increasing authority with four environmental companies, including general manager of BVER Environmental Inc., which became one of the nation’s top companies in the field.


He started Top Gun Environmental in 1981, then merged it with two other companies to gain equipment and personnel and expand services. Those companies later split apart to go into different specialties. Mraovich started AET Robotics five years ago and serves as president and CEO.


AET still offers services such as hazardous materials management and transportation, waste minimization, industrial cleanup, site contamination investigation, and mold and bacteria testing. Mraovich added the inspection business because he saw a need for better ways to investigate pipe problems.


“At the time we entered the inspection business, all that was really available was CCTV,” Mraovich says. “Everybody needed more capability. On CCTV, you can look at a pipe and you’d swear it’s in pretty good shape. Then you look at the comparable laser image beside it, and you see that the pipe is more than 40 percent out of round in ovality. The naked eye is deceiving when you’re looking at a tubular image in distance. Even though our cameras are adjusted for barrel distortion, you still get that effect.”


Another challenge was inspecting large-diameter pipes without bypassing and without excavating. “One of the biggest problems we ran into was the high cost of pumping around large water lines and collectors,” Mraovich says. “That’s ridiculously expensive, and we’ve come up with ways to avoid that.”


Among the company’s favored tools is a float rig for inspecting large pipes while they are charged with wastewater or other fluids. The unit includes four high-definition digital video cameras, a laser profiler above the float, and a sonar profiler below.


“We have the software configured so that we get three images: a laser image above the waterline, a digital video image above the waterline, and a sonar image below the waterline,” Mraovich says. “From those images, we can tell how much debris is there, and detect any cracks, intrusions, deformities or other defects. We get all the information in one shot, and the pipe can be running at three-fourths full.”


Multiple tools

That’s not the only weapon in the AET arsenal. The company uses robotic camera units and submersible vehicles to inspect tanks, including potable water tanks in cities. “All potable water tanks need to be inspected every three years,” Mraovich notes. “They used to have to send divers in. That’s extremely costly, and some of the areas inside the tanks are too small for divers to have access. We have a mini-sub designed just for that purpose. It goes right down in and takes exact videos of every single thing.”


AET uses laser profilers from CleanFlow Systems Ltd. It gets sonar units from SeaBotix Inc., and submersible vehicles from SeaBotix and VideoRay LLC.

For CCTV surveys, the company uses OZ II and OZ III cameras, Mudmaster transporters modified with electric lifts for very large pipes and tunnels, steerable Pipe Ranger crawlers, Ultra Shorty crawlers, and other CUES Inc. equipment. The firm uses push cameras and pole cameras from Envirosight LLC.


All the inspection technologies interface with Granite XP pipe survey software (CUES Inc.), Infor Public Sector/Hansen Technologies infrastructure management software, and ESRI geographic information systems (GIS). “We GIS and GPS map everything we do, so it will go right into any of the GIS that are out there,” says Mraovich.


Field to desk

AET does not simply buy and deploy the best available technology. The firm has a strategic relationship with CUES Inc. for research and development on CCTV, laser and sonar technology. The company also has close ties to the Civil Engineering Department at Clemson University (see sidebar).


“We have mixed and matched and modified everything to suit specific needs,” Mraovich says. “Engineers design things, but engineers don’t work in the field. So when we buy a piece of equipment, it may work really well for specific applications – but every application is different. So we’ve designed different wheels, tires and lifts and different hookups for our CCTV equipment. We’ve also added software to enable it to do all the things we need to do.”


For example, instead of simply mounting inspection equipment in a truck or van, as municipal departments do, AET uses 28-foot trailers that carry an air-conditioned Kubota 4-wheel-drive vehicle that in turn carries the inspection gear.


“The Kubota can go anywhere,” Mraovich says. “We can get off the road. We do work up in the mountains and everywhere. We send the video signal back to the trailer, and the technician working at the front of it can watch what’s going on in the field on a 42-inch plasma screen TV.


“In addition, the engineering department at Clemson has come up with a way to give us a live feed over the Internet. That means as a customer, you can log onto our Web site, get a password key for your project, sit in your office in Virginia Beach or wherever, and observe. There will be a five-minute delay, but you can see live video of what’s going on in the field on your project.”


For underwater work, the company can use a SeaBotix submersible transporter with a 4-wheeled crawler skid, enabling it to track along a tank or pipe bottom while the operator uses the thrusters to keep it down. “For metal tank inspections and for some metal pipelines, we’ve come up with magnetic track,” Mraovich says. “It sticks right on a wall, so we can climb up the side of a tank if need be to do our video work.”


On the road

The AET business mix is about 40 percent industrial and 60 percent government – city, county, federal and state, including departments of transportation. The industrial work mainly involves tanks, underground piping, and process piping. Much of the business comes through contracts with major engineering firms, such as Dennis Corp., Florence & Hutcheson, and URS.


When working around the continent, AET typically dispatches one or two experts to investigate the project and determine the best people and best equipment for the job. The company then sends the necessary specialists and inspection equipment. The AET personnel hire labor locally and contract as needed for cleaning equipment.


“It’s not wise to put people on the road and pay per diems,” Mraovich says. “And often, until you get to the job site and investigate, you’re not really sure what equipment and how many people you need. It might start out one way today, but in three days you find a bunch of problems, and now you need two vacuum trucks, a sewer jetter, and repair equipment. We sub all that to the people we work with on contract.”


When working close to home in the southeastern United States, AET relies on Phillips Recoveries of Pelzer, S.C., for cleaning and ancillary equipment. “The owner, Mike Phillips, has been a friend for a long time,” Mraovich says. “He provides us with all the vacuum trucks and other equipment we need.”


Better things coming

While AET finds itself on the leading edge of inspection, staying there is always a challenge. “When I was in college, we used engineering slide rules,” Mraovich says. “If you buy a computer today, by this time next year you need another one, because it’s outdated. The technology is moving so fast.”


One focus of R&D is the detection of sinkholes, a major problem for water and sewer utilities across the United States. A pipe inspection may readily detect a crack through which water may be leaking, but it leaves no clue to the presence and size of voids that may exist outside the pipe.


AET is developing a ground-penetrating radar (GPR) unit with a spinning head that can travel through a pipe on a tractor and continuously create an image of voids around the entire circumference. “So if you inspect a pipe and observe a crack, we can take a picture behind that pipe and determine the size of the void that has been created,” Mraovich says.


It’s easy to see what kind of disasters that might prevent – and harder to guess what will come next down the AET Robotics R&D pipeline.


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