PROJ00507 - Laserfiche WebLink

Home Browse Search

I I I I I I I I I I I I I I I I I I I There are numerous install at; ons of thi s type of pi pe in the Cortez area including the recently completed Cortez main raw water supply line from the Oolores Canal that conveys the water that will supply the Towaoc pipeline. Mortar-lined and coated steel pipe is similar to concrete cylinder pipe, except all required steel is in the cylinder, rather than in cylinder and rods. Because of the similarity and the reported slightly higher plant cost, the PCCP pipe was not consi~ered in the cost comparison; however, since the manufacturer of the PCCP also manufactures steel pipe, the pipe offering the most economical oackage at the time will be selected for consideration. 3.5.2 PVC Pressure Pipe PVC oipe is essentially noncorrodible pipe. No cathodic protection, corrosion monitorinq, or special coatinqs are required. The stan~ard laying length of PVC pipe is 20 feet. Various coupling systems are available, but for an application like the Towaoc \~ater supply line, the manufacturer recommen~s a simple slip-on, gasketed, bell-and-spigot joint. Long-radius curves (300 feet for 1 2-i nch pi pe and 350 feet for 14-i nch pi pe I can be made by sl i ghtly bending the pipe between joints. There is virtually no deflection obtained at the joint. Standard fittings are available for sharp bends. PVC is reported to have goo~ flow characteristics because of the smooth i nteri or; however, the coupl i ng system results in a head loss that negates some of the advantage of the smooth interior. In designing the pressure classes for PVC pipe, consi~eration must be given to the fact that the strength of PVC does ~ecay with time. The desiqn of PVC pipe is base~ on standar~ practices as follows: 11.. Establish the reqression line throuqh long-term hydrostatic pressure testing (ASn~ 2992) B. I)etermine the hydrostatic design basis (HOB) in accordance with ASTM 0 2837. 3-19 1060c