รายละเอียดเอกสาร

This practice provides a means to determine an allowable tensile load (ATL) value for a polyethylene gas pipe that is to be installed underground using methods that pull the pipe into a trench (cut or plowed), bore hole, casing pipe, or the like. The ATL value takes into account pipe size, tensile yield strength, pipe temperature, and pulling load duration. The ATL is used to set the break-away strength for a “weak-link” device, or as a limit setting for other devices that control the maximum pulling force exerted by equipment used to pull polyethylene gas pipe into an underground location, or to determine if pulling equipment can exert pulling force greater than the ATL value for the gas pipe being installed. A weak-link device is installed where the pipe pulling equipment is connected to the polyethylene gas pipe. If pulling load exceeds the ATL limit, the device de-couples the pipe from the pulling equipment. Other measures or equipment that limit the pulling force on the pipe are also used. When the ATL value is compared to the pulling force developed by the pull-in installation equipment and equipment cannot exert pulling force greater than the ATL value, a weak-link or other device for limiting the pulling force is not necessary.

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