When is it a good time to rehabilitate or repair a water pipe? Certainly, when the news crews are filming the break, the time for a proactive approach has passed.
However, there are several factors to consider when deciding whether to do a repair, retrofit, or replacement, industry experts note. They include the pipe’s condition, taking into account corrosion, wall thickness, and age. Another is its substrate: cast iron, asbestos cement, or ductile iron. Other factors are the project timeline, budget, cost to customers, and cost of delays to the traveling public during construction.
When is it a good time to rehabilitate or repair a water pipe? Certainly, when the news crews are filming the break, the time for a proactive approach has passed. However, there are several factors to consider when deciding whether to do a repair, retrofit, or replacement, industry experts note. They include the pipe’s condition, taking into account corrosion, wall thickness, and age. Another is its substrate: cast iron, asbestos cement, or ductile iron. Other factors are the project timeline, budget, cost to customers, and cost of delays to the traveling public during construction. [text_ad] To be certain, pipe rehabilitation and replacement costs money. There are strategies to address that, notes Maury Douglas Gaston, manager of marketing services for the American Cast Iron Pipe Co., who recently completed a two-year tour of 60 major utility firms. Gaston, a member of the American Water Works Association’s (AWWA) A21-Ductile Iron Pipe & Fittings Committee and chairman of Subcommittee 1, which governs ductile iron pipe design and manufacturing standards, says that from a financial standpoint, “the best utilities are the ones that have small, incremental rate increases every year regardless of whether they need it or not. Regardless of how much capital improvement money they’re spending the next year, a compounding 2 or 3% rate increase every year is going to be palatable to the ratepayers and you’re going to avoid the public outcry if you have a 9 or 12% increase every five years,” he says, adding that the incremental rate increases add cash to the balance sheet and improve the bond rating. The American Cast Iron Pipe Co. manufactures ductile iron and spiral welded steel pipe from 4-inch to 12-foot diameters. The company also manufactures valves from 2 to 66 inches in diameter, fire hydrants, and bolted and unbolted joints that are available restrained to prevent joint separation or unrestrained if thrust is not an issue. “Our Flex-Ring joint pipe is restrained, has five degrees joint deflection, and has proven to be very effective in horizontal directional drilling installations where a bore path is created, and then the pipe is either pre-assembled above ground and pulled through the bore path, or can be installed with the cartridge method where one 20-foot joint is assembled and pulled through,” points out Gaston. The American Cast Iron Pipe Co. has done horizontal directional drilling installations in a variety of large diameters up to 42 inches, and in lengths as long as 1,000 feet or more for smaller diameters, says Gaston. Flex-Ring pipe also has proven to be very effective in pipe bursting applications, he adds. The company has furnished a number of spiral-welded steel pipe projects where a larger diameter deteriorated pipe is slip-lined with a slightly smaller spiral-welded pipe, and the remaining space is sometimes grouted with sand or another material. Cast iron pipe has been used for more than 200 years in the United States, points out Gaston, adding that old cast iron pipe was not lined. “If you see a photograph of a clogged-up, rusty-looking pipe, chances are that it was installed well before 1930, because in the period between 1923 and 1930, the cast iron pipe industry began to apply a thin lining of cement inside iron pipe which prevents tuberculation—a buildup of mineral deposits inside an unlined cast iron pipe.” [text_ad use_post='27751'] Being that pre-1920 cast iron lines were not cement lined, many of them tuberculated, restricting flow. “Typically, a utility would scour out that tuberculation, flush it out, and then cement line the pipe in situ,” he adds. Gaston says Boston engaged in an in situ cement lining program in the early 1980s, cleaning and cement-lining all cast iron pipe. The initial intent was to first replace the oldest pipes, pinpointing priorities through conducting an assessment. But that assessment revealed that many of Boston’s oldest pipes were, in fact, in some of the best conditions. Using that as an example, Gaston says he believes assessments should be mandatory before taking actions on pipes.
To be certain, pipe rehabilitation and replacement costs money. There are strategies to address that, notes Maury Douglas Gaston, manager of marketing services for the American Cast Iron Pipe Co., who recently completed a two-year tour of 60 major utility firms.
Gaston, a member of the American Water Works Association’s (AWWA) A21-Ductile Iron Pipe & Fittings Committee and chairman of Subcommittee 1, which governs ductile iron pipe design and manufacturing standards, says that from a financial standpoint, “the best utilities are the ones that have small, incremental rate increases every year regardless of whether they need it or not. Regardless of how much capital improvement money they’re spending the next year, a compounding 2 or 3% rate increase every year is going to be palatable to the ratepayers and you’re going to avoid the public outcry if you have a 9 or 12% increase every five years,” he says, adding that the incremental rate increases add cash to the balance sheet and improve the bond rating.
The American Cast Iron Pipe Co. manufactures ductile iron and spiral welded steel pipe from 4-inch to 12-foot diameters. The company also manufactures valves from 2 to 66 inches in diameter, fire hydrants, and bolted and unbolted joints that are available restrained to prevent joint separation or unrestrained if thrust is not an issue.
“Our Flex-Ring joint pipe is restrained, has five degrees joint deflection, and has proven to be very effective in horizontal directional drilling installations where a bore path is created, and then the pipe is either pre-assembled above ground and pulled through the bore path, or can be installed with the cartridge method where one 20-foot joint is assembled and pulled through,” points out Gaston.
The American Cast Iron Pipe Co. has done horizontal directional drilling installations in a variety of large diameters up to 42 inches, and in lengths as long as 1,000 feet or more for smaller diameters, says Gaston. Flex-Ring pipe also has proven to be very effective in pipe bursting applications, he adds.
The company has furnished a number of spiral-welded steel pipe projects where a larger diameter deteriorated pipe is slip-lined with a slightly smaller spiral-welded pipe, and the remaining space is sometimes grouted with sand or another material.
Cast iron pipe has been used for more than 200 years in the United States, points out Gaston, adding that old cast iron pipe was not lined. “If you see a photograph of a clogged-up, rusty-looking pipe, chances are that it was installed well before 1930, because in the period between 1923 and 1930, the cast iron pipe industry began to apply a thin lining of cement inside iron pipe which prevents tuberculation—a buildup of mineral deposits inside an unlined cast iron pipe.”
Being that pre-1920 cast iron lines were not cement lined, many of them tuberculated, restricting flow. “Typically, a utility would scour out that tuberculation, flush it out, and then cement line the pipe in situ,” he adds.
Gaston says Boston engaged in an in situ cement lining program in the early 1980s, cleaning and cement-lining all cast iron pipe. The initial intent was to first replace the oldest pipes, pinpointing priorities through conducting an assessment. But that assessment revealed that many of Boston’s oldest pipes were, in fact, in some of the best conditions. Using that as an example, Gaston says he believes assessments should be mandatory before taking actions on pipes.
