Journal of The New England Water Works Association - June 2015 - (Page 106)

Restrained Joint Ductile Iron Pipe Proven Reliable for Stressful Utility Installations By Kenneth Rickvalsky* Received August 18, 2014 ABSTRACT This article examines the interactive role of gaskets, bells, and spigots in the containment of pressurized fluids; along with the reliable mechanics of specialized restrained joint pipe systems throughout the water and sewer industry. From basic design criterion to various products and methods commonly utilized, the reader will come away with a greater understanding of what's truly needed, as well as what's often overplayed or misguided. Topics and Learning Objectives Included in this article: * The Greatness of Gaskets * What Restrained Joints Are All About * The Needs and Deeds of Restraint Joint Piping Systems * Details of Design and Installations, including Horizontal Directional Drilling * Gaskets That Provide Joint Restraint by Themselves * The Beauty of Wedge-Action Retainer Glands Gaskets Are Great Standard issue rubber gaskets are the reliable workhorse of any ductile iron pipe joint. They provide long-lasting flexibility and a watertight seal against internal pressures upwards of 1,000 psi. What they don't do however is bind the joint longitudinally against such forces. In fact, regardless of diameter, without assistance from other variables, a push-on or mechanical joint would calmly separate lengthwise against pressures as low as 50 psi. In most pipe joints, the spigot end buries and sets into the bell approximately 2 or 21/ 2 inches past the compressed gasket. The weight of the pipe itself, along with the weight of its contained fluid, the weight of the trench backfill in contact with the pipe and associated soil-to-metal friction all play a part in stabilizing the pipe joint against aforementioned internal forces. When the internally generated thrust forces caused by fluid transport and directional changes in the pipeline exceeds the "natural forces" mentioned previously, the answer is simple and sure ... RESTRAINED pipe and fitting JOINTS. What's It All About Non-restrained Tyton joint - cutaway view *National Product Engineer, McWane Ductile, Marketing and Specifications Division, 183 Sitgreaves Street, Phillipsburg, NJ 08865, (609) 290-7701, ken.rickvalsky@mcwane.com 106 Journal NEWWA June 2015 Think of how you feel when riding a roller coaster or a log flume ride that suddenly juts left and up after a quick downhill thrill! You feel as if all things are being thrown to the right, and hard. That's the law of equal and opposite reactions. Same things happens from within a pipe carrying water or other fluids at each change in direction, especially so at fittings. The old-fashioned answer was huge blocks of poured concrete behind and against the fittings, with the theory being that if the fitting is "controlled", no adjacent joints in the pipeline are in jeopardy. Great idea, except today's infrastructure spaghetti and pace of construction have minimized the effectiveness and tolerance for space-hogging and longtimeto-set thrust blocks being utilized. The modern answer is RESTRAINED JOINTS for pipes and fittings instead of cumbersome thrust blocks. Each

Table of Contents for the Digital Edition of Journal of The New England Water Works Association - June 2015

Officers of the New England Water Works Association
NEWWA 2015-2017 Meeting & Event Schedule
On The Cover
Cyanobacteria in Reservoirs: Causes, Consequences, Controls
With a Little Help from our Friends: Collaborating to Protect a Water Supply
Salem's Folly Hill Reservoir: Inspecting and Rehabilitating a Century-Old Concrete Tank
Restrained Joint Ductile Iron Pipe Proven Reliable for Stressful Utility Installations
Water System Profile: Southington, Connecticut Water System
Proceedings
Urgent Need for Papers!!
Obituaries
Guidelines for the Preparation of Papers for Publication in the Journal of the New England Water Works Association
Guidelines for the Peer Review Option of the Papers Appearing in the Journal of the New England Water Works Association
Index to Advertisers

Journal of The New England Water Works Association - June 2015