Baltimore County Embraces HDPE Pipe
In waterfront communities all across the country, such as those along a 175-mile stretch of eastern Baltimore County in Maryland, pleasure boating is a multi-million dollar industry.
For the past two years, luxury boat owners in Dundalk, Essex and Middle River have been storing their craft year-round at the Sunset Harbor Marina, home of the county’s first “boatel”—a three-level facility with capacity to store craft up to 40 ft long.
One of the selling points of the new 62,000-sq-ft, $3-million facility was a state-of-the-art fire protection sprinkler system. For those boat owners, protecting against fire means protecting their investments.
As county officials were making decisions on how to upgrade the local infrastructure overall, as well as accommodate the boatel, they were reminded of a persistent problem.
“The existing 8-in. ductile iron pipe was installed in 1968 and had about 10 failures in the last 10 years,” said project engineer Mike Mazurek of the Baltimore County Department of Public Works. “That particular section of the northeast part of the county near Chesapeake Bay has very corrosive soils.”
Mazurek said corrosion in the ductile iron pipe generated longitudinal cracks that would split the pipe beyond what a normal repair coupling could correct.
“We were having to go in and replace whole sections of pipe, which is a six- to eight-hour process of digging, cutting and laying new pipe,” Mazurek said. “That’s a long time to shut down a line and inconvenience businesses and residences.”
The solution was to solve the problem long term, rather than continue a series of short-term fixes. Baltimore County installed more than 2,000 ft of smoothwall high-density polyethylene (HDPE) water pipe.
The result was positive for the residents in two ways—the water main that served the existing homes and businesses was upgraded, and the marina boatel now benefits from a reliable, leak-free water distribution system for fire protection.
The Browns Road project included 1,125 ft of 12-in. HDPE pipe and 1,200 ft of 16-in. pipe. Mazurek added that for the residential customers now served by this new water main, the installers had no trouble connecting the service lines from the main to the houses.
“It really was a two-birds-with-one-stone scenario,” Mazurek said. “As areas like these continue to grow, the infrastructure needs to be able to grow with them. This system has performed very well, and we’ve put in several other HDPE pipe systems since the Browns Road project [in May 2004].”
For example, the Lower Back River Neck Peninsula project will serve about 200 homes that were previously on well water. The $4.9-million job was started in December 2005 and will consist of HDPE pipe in the following amounts: 4,000 ft of 16-in. pipe; 19,100 ft of 12-in. pipe; 12,200 ft of 8-in. pipe; and 220 ft of 6-in. pipe.
Mazurek said the Lower Back River project should take about a year and involves horizontal directional drilling (HDD). Underground water lines can be installed using HDD—a process that uses drilling technology to bore a small hole from one location to the next. Once the drill rod comes to the end of the bore, the new pipe is attached and pulled back, eliminating open excavation. This technology can be used to install water lines under roads, railroads, ponds, lakes, streams, industrial buildings, etc., without the impact of open excavation.
The county also replaced its 1920s cast iron pipe in a residential area called Maryland Manor that had started to experience water main failures and poor water quality. It cost the county $888,000 to install 1,320 ft of 12-in. HDPE pipe and 2,592 ft of 8-in. HDPE water main. This job was done using open-cut construction and is currently complete. Nearly 100 water services were replaced.
“We have had very good success with all of the HDPE pipeline projects here in Baltimore County,” Mazurek said. “We have used DIPS HDPE pipe sizes with a dimension ratio of DR 11. That made for an easy transition when tying into the existing cast iron and ductile iron pipe that currently exists in our distribution network,” he added.
“We have had zero callbacks on these projects due to a combination of dealing with reputable contractors, in conjunction with good inspection from our Baltimore County Construction Inspection and Contracts Division,” Mazurek said.
Keeping corrosion, leaks at bay
It’s accepted within the water industry that about 75% of cities report that they’re aware corrosion is a problem in their water pipes. But in some cases, the city officials believe the corrosion is a minor issue.
Engineers at the Plastics Pipe Institute (PPI) say metal pipe manufacturers strive to prevent corrosion by either coating their base materials with electrically insulating materials or providing some sacrificial material, which will corrode before the base metal. Because corrosion is an electrolytic process that requires the presence of electrically conductive materials—and polyethylene is a non-conductor—polyethylene is not subject to corrosion.
“Unfortunately, it’s that catastrophic event that prompts them to take a closer look at what condition their infrastructure is really in,” said Camille Rubeiz, P.E., director of engineering for PPI. “That’s sometimes what it takes to bring about changes or improvements.”
Fortunately for Baltimore County, officials are addressing the infrastructure needs before such catastrophic events can take place.
“Traditionally, water leakage is something that is common in older water pipe systems,” said the Browns Road project contractor and project engineer Vern Dettman of J. Fletcher Creamer & Son, Inc. “But in the Browns Road case, the pipeline ends in a very low-lying area. Another problem they were having was poor drainage. For the new system, there is a zero-allowable leakage tolerance.”
According to recent statistics cited by PPI, public water supply systems in the U.S. lose an average of 11% of the water they carry due to leaks, cracked pipes and other factors. Water systems serving more than one million people lose even more water. More than three out of every 20 gal of water entering these systems leak out.
According to reports in The Washington Post, about a quarter of the water handled in that city’s treatment plants leaks out through a deteriorating infrastructure, which can lead to contaminated drinking water and higher water bills for taxpayers. The Washington, D.C. metro area has about 66 million gal of “unaccounted for” water per day.
Rubeiz cites an example of why infrastructures can sometimes go years without preventative maintenance. Citizens in San Francisco recently voted to freeze their water rates at 1999 levels through the year 2006. The reason was they thought too much money was being spent on improvements to the system.
Meanwhile, stories with headlines like “Hayes Valley Water Line Breaks,” were appearing in the San Francisco Chronicle in late 1999. An excerpt from that newspaper article stated, “A spokesman for the Water Department said the cast-iron pipe, like many in the city’s water system, apparently has been in the ground since the 1930s.”
The infrastructure price tag
In its 2005 report card on infrastructure, the American Society of Civil Engineers stated that drinking water received a grade of “D-” and faces an annual shortfall of at least $11 billion to replace aging facilities that are near the end of their useful life and to comply with existing and future federal water regulations.
The shortfall does not account for any growth in the demand for drinking water over the next 20 years. Federal funding for drinking water in 2005 remained level at $850 million, less than 10% of the total national requirement.
“Back when the systems like the original ones in Baltimore County and many others were installed, engineers installed the best pipe they had available at that time,” Rubeiz said. “But that pipe, some of which was installed several decades ago, has served its design life.”
“Water infrastructure improvements must be a priority for public officials,” Rubeiz said.
Solutions can be painless
“I was very familiar with HDPE as a piping material (before the Browns Road project),” Dettman said. “We’ve installed it a lot in fiber optic applications, pipe bursting, sewer applications and electric conduit applications. On Browns Road, we started out with 16-in. lines, went to 12-in. about halfway down, and used side-saddle fusion to connect to the hydrants. It was very easy to put in.”
“Most contractors in the field report that fusing the PE pipe together is much simpler than they envision,” Rubeiz said. “It’s a major way that this material differentiates itself from the other pipe materials.”
Dettman added that traffic along Browns Road—a residential street—was not disrupted in the process. All of the fusion was done above ground; the existing pipe was just left in place, and the HDPE pipe was simply lowered into the trench.
“Everything could be cut right on site,” Dettman explained. “Even different sizes of pipe. It’s a great way to install side saddles—to hydrants, laterals—it all fuses right together at the job site.”
“Many of the features of HDPE pipe were a benefit to the engineers on this project,” Rubeiz said. “The above-ground fusion, light weight, ease of installation, and especially the leak-free system. The business of protecting multi-millions of dollars worth of property from fire must be done with a reliable water delivery system.”
Fused pipe means strong joints
PE pipe for pressure applications is the only pipe that uses heat fusion to join two pieces together. The resulting connection is as strong if not stronger than the pipe itself. In fact, PPI estimates that more than 90% of new natural gas distribution pipes installed in the U.S. are PE pipe.
Heat fusion (or butt fusion) is accomplished by clamping two pipe pieces into a fusion machine and facing the ends of the pipes to remove any contamination and bring the ends perpendicular to the axis of the pipe.
The ends are then heated with a resistance heater according to the pipe manufacturer’s recommendations. When the proper heat is established, the heater is removed and a fusion force is applied between the pipe ends. This force is held until the joint is cool.
“If we’re trusting our safe delivery of natural gas to PE pipes, what’s stopping other communities from following the lead of places like Baltimore County for their water infrastructure upgrades?” Rubeiz said.