Design and Construction Standards - Tualatin Valley Water District

Water Mains Section 3necessary. Pipelines intended to be straight shall not deviate from straight alignment atany joint in excess of one inch horizontally or vertically.3. At each joint, dig bell (joint) holes of ample dimensions in the bottom and sides ofthe trench to allow the joint to be properly made and to permit easy visual inspection ofthe entire joint.4. Provide ample means of removing all water entering the trench, according toSection 2.1.8. Do not lay pipe in water or when, in the opinion of the District Engineer orInspector, trench conditions are unsuitable.5. Do not drop pipeline materials into the trench. Carefully lower all pipe andappurtenances into the trench by means of a crane or other suitable equipment toprevent damage materials and protective coatings.6. Unless otherwise directed, lay pipe with bell end facing in the direction of thelaying. For lines on steep slopes, face bells upgrade only.7. Cleaning pipe and fittingsi. Clean the outside of the spigot and the inside of the bell with a wire brush.Remove all lumps, blisters, and excess coal tar coating from the bell andspigot ends of each pipe.ii. Wipe all dirt, grease, and foreign matter from fittings and the ends of MJpipe and push-on joint pipe.iii. Do not allow any foreign material to enter the pipe during storage orplacement in the trench.8. Restrained Joint Pipei. Lay and join pipe with restrained type joints in strict accordance with themanufacturer's recommendations.ii. After the first length of restrained joint pipe is installed in the trench, securepipe in place with approved backfill material tamped under and along sidesto prevent movement. Keep ends clear of backfill. After each subsequentsection is joined, place backfill to the spring line to prevent movement.iii. Lubricant for the pipe gaskets shall be furnished by the pipe manufacturer,and no substitutes will be permitted under any circumstances.9. Mechanical Joint Fittingsi. Install the particular fittings furnished in accordance with themanufacturer's recommendations.ii. Clean the ends of the fittings to remove all dirt, mud, and foreign matter bywashing with water and scrubbing with a wire brush.iii. Slip the gland and gasket on the plain end of the pipe. If necessary,lubricate the end of the pipe to facilitate sliding the gasket in place. Thenguide the fitting onto the spigot of the pipe previously laid.10. Flanged Fittingsi. Bolts for flange fittings shall be full-nut installation (i.e., three full threadsshowing past nut).TVWD Water System Standards June 2012 Page 3-8