FAQ: Can FIELD LOK® Gaskets be used with TRIM TYTON® Plugs?
U.S. Pipe does not recommend the use of a FIELD LOK® Gaskets with a TYTON® Plugs. Due to the fact that you cannot get the gasket out unless you cut the pipe bell off because of the flange on the end of the plug. If the plug is pushed in too deep then the set screw holes can be in the gasket bulb causing it to leak. Since the installation was performed with a FIELD LOK Gasket, you cannot pull it out and the fitting or pipe bell would have to be scrapped.
FAQ: What are the UL and FM listings for U.S. Pipe products?
U.S. Pipe's primary method of thrust restraint are restrained joints.
A column of liquid moving through a pipeline has momentum or force that tends to separate the joints at changes in direction (bends and tees), stops (plugs, caps, or closed valves), and changes in size (reducers). Some means must be used to prevent joint separation to maintain the integrity of the pipeline. Three such means are thrust blocks, tie rods, and restrained joints.
Thrust blocks are usually poured-in-place concrete. They must be engineered with full knowledge of the pipeline operating characteristics and of soil type and bearing strength. They must bear against virgin soil, because thrust forces in the pipeline are transmitted through the thrust block to the soil. Depending on these conditions, thrust blocks can be quite massive. The use of thrust blocks can delay completion of the project to allow the concrete to cure adequately before applying test pressure to the pipeline. If future construction disturbs the thrust block or the surrounding soil, joint restraint and the integrity of the pipeline can be jeopardized.
Tie rods usually involve some sort of fabricated steel harness on either side of the joint held together by tie-rods. This type of joint restraint is generally labor intensive. A tie-rod type of joint restraint must be adequately protected against weakening by corrosion, or else the joint restraint and integrity of the pipeline can be jeopardized.
Restrained joints are designed to hold the joint together against a rated pressure while the pipeline transfers the thrust force to the surrounding soil envelope. In order to calculate the footage of restrained pipeline necessary for the thrust force to be fully dissipated to the soil, it is necessary to know pipe diameter, maximum anticipated internal pressure, depth of cover, soil type, and trench construction type, as well as the configuration (e.g., bend angle) requiring restraint. The calculated restrained footage must be installed on each side of the fitting. Since polyethylene encasement for external corrosion protection reduces the friction between the pipeline and the surrounding soil, the calculated restrained footage is usually multiplied by a factor of 1.5 for pipelines where polyethylene encasement is to be installed.
Mechanical joint retainer glands, both common and proprietary design, are available for use where such devices must be used (e.g., a special valve or meter). However, U.S. Pipe does not recommend their use. Restrained push-on joints manufactured by U.S. Pipe are less susceptible to external corrosion, offer appreciably more deflection, and are much less labor-intensive to install.
FAQ: Aren't all pipe lubricants pretty much the same?
No. It's always a good practice to use the lubricant furnished by the manufacturer. Our lubricant is formulated to be nontoxic, does not support bacterial growth, has no deteriorating effects on the gasket material, and is water soluble so it readily flushes away prior to acceptance testing of the pipeline. It doesn't impart any taste or odor to the water in the pipeline, and meets the requirements of AWWA/ANSI C111/A21.11.
Because it is water soluble, it's sometimes difficult to maintain lubrication on wet surfaces such as a wet trench or stream crossing. In these conditions, it's advisable to apply the lubricant liberally – as much as three times as much as would normally be used.
We do not recommend the use of spray-on lubricants.
FAQ: Are push-on and mechanical joints rated for the same pressure as the pipe or higher? What is the maximum rated pressure for push-on and mechanical joints?
Ductile Iron push-on and mechanical joints are covered in ANSI/AWWA C111/A21.11 "Rubber-Gasket Joints for Ductile-Iron Pressure Pipe and Fittings." Section 4.2.2 of that standard states: "The mechanical and push-on joints shall have the same pressure rating as the pipe or fitting of which they are a part." In other words, if the pipe is rated for 150 psi working pressure plus 100 psi surge (250 psi), so is the joint. If the pipe is rated for 350 psi working pressure plus 100 psi surge (450 psi), so is the joint.
This is not to say that Ductile Iron pipe and push-on and mechanical joints cannot be rated above 350 psi working pressure plus 100 psi surge (450 psi). Footnotes under Table 7 in ANSI/AWWA C151/A21.51 "Ductile-Iron Pipe, Centrifugally Cast, for Water" state: "Ductile Iron pipe for working pressures higher than 350 psi is available." There are numerous Ductile Iron pipelines operating at working pressures well in excess of 350 psi throughout the United States. Additionally, Ductile Iron’s push-on joints have been proven effective in actual tests and/or service with at least 1,000 psi internal pressure, 430 psi external pressure, and 14 psi negative air pressure with no leakage or infiltration.
FAQ: Which ANSI/AWWA standards apply to fittings?
AWWA/ANSI C110/A21.10: Ductile Iron and Gray Iron Fittings, 3 in. through 48 in. For Water and Other Liquids
AWWA/ANSI C153/A21.53: Ductile Iron Compact Fittings, 3 in. through 24 in. and 54 in. through 64 in. for Water Service
AWWA/ANSI C111/A21.11: Rubber-Gasket Joints for Ductile-Iron Pressure Pipe and Fittings
AWWA/ANSI C104/A21.4: Cement-Mortar Lining for Ductile-Iron Pipe and Fittings for Water
AWWA/ANSI C116/A21.16: Protective Fusion Bonded Epoxy Coatings for the Interior and Exterior Surfaces of Ductile-Iron and Gray-Iron Fittings for Water Supply Service
AWWA/ANSI C105/A21.5: Polyethylene Encasement for Ductile-Iron Pipe Systems
AWWA/ANSI C600: Installation of Ductile-Iron Water Mains and their Appurtenances
FAQ: What is the purpose of the "testing allowance" in ANSI/AWWA C600?
ANSI/AWWA C600 "Installation of Ductile-Iron Water Mains and Their Appurtenances" requires that newly installed Ductile Iron water mains be hydrostatically tested at not less than 1.25 times the working pressure at the highest point along the test section and not less than 1.5 times the working pressure at the lowest point of testing.
After the air has been expelled and the valve or valves segregating the part of the system under test have been closed, pressure is then normally applied with a hand pump, gasoline-powered pump, or fire department pumping equipment for large lines. After the main has been brought up to test pressure, it is held at least two hours and the make-up water measured with a displacement meter or by pumping the water from a vessel of known volume. The make-up water is called the "testing allowance," and the allowable amount is a function of length of pipe tested, nominal diameter of the pipe, and the average test pressure. The hydrostatic pressure test helps to identify damaged or defective pipe, fittings, joints, valves, or hydrants, and also the security of the thrust restraint system.
The "testing allowance" is not a "leakage allowance." Properly installed Ductile Iron pipelines with properly assembled joints are bottle-tight and do not leak. The "testing allowance" is, however, a practical measure used to maintain the pressure, which might actually drop because of factors other than leakage, including trapped air, absorption of water by the cement lining, extension of restrained joints and other small pipe-soil movements, temperature variations during testing, etc.