Potable water” is defined as water suitable for drinking by humans, and as you would imagine, a number of government standards apply. But not all potable water is for drinking; much of it is used for bathing and washing, while a slightly different standard applies to potable water for agriculture.
In many parts of the world, there is not enough potable water to supply the needs of the population. Certainly, the U.S. has suffered periodic regional droughts; therefore, transporting potable water from point to point is a major responsibility.
Since 1969, centrifugally cast fiberglass pipe and joints have been used for potable water service in numerous applications around the globe.
The centrifugally cast, fiberglass-reinforced, polymer mortar (CCFRPM) pipe’s high-strength pipe wall, leak-free couplings and hydraulically efficient interior can provide long maintenance-free life, in addition to savings passed along due to decreased pumping cost.
The CCFRPM pipe’s inherent corrosion resistance means that even in corrosive soils or electrically charged areas, no cathodic protection may be needed.
Tested and approved
CCFRPM potable water pipes and joint gaskets, manufactured by Hobas Pipe, have been tested by the National Sanitation Foundation (NSF) in Ann Arbor, Mich., and meet NSF’s Standard Number 61. NSF/ANSI Standard 61: Drinking Water System Components—Health Effects is the nationally recognized health effects standard for all devices, components and materials that contact drinking water.
In addition to the NSF compliance and certification, the Hobas CCFRPM pipes are manufactured in accordance with, and surpass, the performance requirements of AWWA C950, Fiberglass Pressure Pipe Standard.
The water pipes are suitable for many types of installations, including open cut (direct bury), slip lining, jacking or microtunneling, tunnel lining and aboveground.
Hydraulically efficient
CCFRPM pipes have been used in a number of installations where they were reconnected to cast or ductile iron pipes. This is possible because the outside diameter of the pipes is the same as a ductile iron pipe in sizes ranging from 18 to 48 in.
The pipes can be assembled using a gasket seal. After they are pushed together, the FWC coupling joints are designed with a burst pressure of at least four times the nominal pressure class. The pipes must also withstand field test pressure of at least one and a half times the rated pressure class with no leakage.
Randy Whiddon, field service manager for Hobas, said, “The ability to fabricate short pipe sections in the field, make connections to other materials and install in a wide range of embedment conditions is a real advantage for installation contractors. The pipe’s time-proven record also appeals to the owners.”
Many municipalities across the country have an ongoing effort to decrease the operation and maintenance costs of pipelines and preserve infrastructure by using leak-free systems.
According to Hobas officials, CCFRPM pipe is regularly selected for several reasons including its flow capacity. The company’s potable water pipes can also deliver energy savings due to the low head loss delivered by the smooth pipe interior. With a Hazen-Williams Coefficient of C=155, the calculated loss compared to a rougher concrete pipe or cement-lined product can equate to substantial cost savings over the duration of the pipeline’s useful life.
Richard C. Turkopp, Hobas vice president of engineering, said, “It works, and it works routinely, solving problems and meeting needs.”
Plant piping in California
Recently, Hobas pipe was utilized in a direct bury installation of new pipelines on a potable water job in California. Overaa Construction of Valley Home, Calif., used the pipe and fittings for the South San Joaquin Water Treatment Plant project.
The 20-ft joints were 60 in. in diameter, 50-psi pressure class and 46-psi stiffness class with push-together FWC couplings.
The pipes were installed on a 6-in. stable bed, with a gravel embedment to 70% of the diameter. They were direct buried with cover depths that ranged from 3.5 to approximately 15 ft.
According to pipe installers at the site, most of the pipe was installed under 10 ft of cover with HS-20 live load.
The plant piping required several special fittings including branch T’s and elbows, which were custom-fabricated.
The new 40-mgd South San Joaquin Water Treatment Plant’s source water comes from the Woodard Reservoir. The water is treated with a plant process consisting of dissolved air flotation pretreatment, lime stabilization and ultra iltration vacuum submerged type membrane filtration.
Onsite chemical feed systems include ferric chloride, hydrated lime, carbonic acid, sodium hypochlorite and sodium hydroxide. Auxiliary facilities include operations and maintenance building, finished water storage facilities, storm water detention basin, water stream management facilities, electric substitution and miscellaneous yard structures.
Because of the recent pipe installation, officials from the South San Joaquin Water Treatment Plant feel that the plant will provide drinking water well into the future.
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