A pull-in-place structural lining method solves grease line issues in a Las Vegas hotel and casino.
A contractor cleaned clogs from a 290-foot-long gravity grease line at Circus Circus Hotel and Casino in Las Vegas, Nev., for a year. As service calls increased in frequency, director of facilities Ron Brown realized he had a serious problem.
The 45-year-old pipe ran 4 feet beneath a concrete service hallway on the first floor. Excavating to replace it would be expensive and interfere with daily operations. A recommendation sent Brown to Nu Flow.
“We inspected the line, but couldn’t see much because the pipe was full of water, grease and debris,” says Nu Flow regional project manager Nick Ghosn. “Our biggest challenge was the unknown in this dark, dirty, forgotten part of the casino.”
To rehabilitate the line, Ghosn chose the Nu Drain start-and-stop pull-in-place structural lining method, which eliminated reinstatements and was more economical. The eight-day project dealt his crew a few surprises.
“We were told to expect a straight run of ABS pipe,” says Ghosn. “Our two-day inspection proved otherwise.”
The SeeSnake camera/locating system (RIDGID) revealed 20 feet of 4-inch cast-iron line running from the street clean-out to a 90-degree elbow. From the bend, 4-inch ABS pipe ran 130 feet before upsizing to 6-inch ABS, which ran 140 feet to the upstream clean-out. Both lengths of pipe had two pairs of 45-degree elbows that dropped elevation 10 feet.
The number of turns in the pipe and its condition made additional access points necessary. Per Ghosn’s specifications, Brown hired a contractor to install two downstream clean-outs and excavate a 4-foot-square hole midway in the line where it upsized. Everyone worked in the hallway during the day, yet most staffers were unaware of the activity.
Ghosn’s crew also found a communal line serving three second-floor kitchens at the upstream end of the grease pipe. He engineered a bypass system, then the casino maintenance staff installed it. At the first-floor level, a 4-inch line from the main buffet dishwashing room and a 3-inch line from the employee dining room teed into the upstream end.
Getting a clear picture
On the third day, the team parked their truck and a 300-gallon trailer-mounted jetter (US Jetting) at the curb by the street clean-out. They spent the morning using a pneumatic heavy-duty Micro-Cutter cable machine (Nu Flow) and various cutting tools to break up the grease in the downstream segment. That afternoon, they jetted the debris, collecting it in a 16-gallon wet/dry vacuum (RIDGID).
Technicians repeated the process the next day, cleaning upstream from the access pit. “The door at the end of the hallway was 15 feet from the curb and our jetter,” says Ghosn. “We dragged in the hoses and went to work. The only reason we ever entered the kitchen was to grab a bite to eat.”
As the pipe’s interior walls emerged, the camera detected a crack running along 80 percent of the crown. Although technicians saw evidence of exfiltration, erosion was not an issue. “The line had a Heat Trace cable to warm the pipe and keep grease flowing,” says Ghosn. “Heating the pipe caused it to crack.” During two and a half days of cleaning, workers removed food, kitchen utensils, plate fragments, 10 pounds of broken glassware and a dozen pieces of flatware from the pipe.
Night by night
Liners were installed over four nights from 11 p.m. to 7 a.m. Before going home, kitchen staff parked mobile food cabinets along one side of the corridor to create an unobstructed wetting-out area. Ghosn’s technicians protected it by laying plastic sheeting on the floor and taping it to the wall. Each night, they gave the grease line a quick cleaning to flush out the day’s debris.
Liners were cut 40 to 50 feet long, the distance between tie-ins or clean-outs. After technicians impregnated the felt with epoxy and inserted the calibration bladder, they attached a pulling cap with D-ring and secured a 1/8-inch cable to it. They mounted a cap with an air connection to the other end of the liner and rolled it up. Meanwhile, another technician tied light polyester string to a little garbage bag and floated it downstream to the insertion point.
“We tie the string to the cable, pull it upstream and off we go,” says Ghosn. “One man unrolls and feeds in the liner while another downstream pulls it through. It isn’t difficult if the pipe is clean.” Only one longer run required a winch.
The liners stopped at one end of a tie-in or clean-out and started at the other end, leaving a 2.5-inch gap. Once a liner was in place, an air compressor inflated 4-inch liners to 10 to 12 psi and 6-inch liners to 12 to 15 psi. As the bladder expanded, it squeezed out enough epoxy to coat the exposed fitting. The epoxy ambient cured in four hours, enabling workers to pull in two or three liners per night.
On the eighth night, technicians pulled in the last liner, flushed the new pipe with water and inspected it. “I told the maintenance staff to disassemble the bypass, and we were done,” says Ghosn. The grease line has had no more backups.