Papers
Plastic Pipes Conference Association # 2018 Las-Vegas
Julian West
Until the late 1950’s, water and sewerage pipe lines used predominantly rigid joints. These were often made from tarred rope and cement mortar. The introduction of ‘flexible’ elastomeric joints allowed angular deflection, transverse shear load and localized pipe deformation without leakage or failure of the joint. This paper presents a brief history of elastomeric seals in water and sewerage pipeline systems, looking at how the existing materials and designs of joints have evolved. It considers the current elastomeric material standards and how these specifications relate to the long-term durability of the joint.
The contact pressure in a joint, decreases over time due to relaxation of the rubber seal. In this time-dependent relaxation process, the rubber relieves a part of the imposed compressive stress by reorientation of the polymer chains in the rubber material. This reorientation is non-elastic and will result in a permanent reduction in contact pressure.
Using recognized and proven ISO methodology, the relaxation threshold value may be chosen as the maximum relaxation acceptable for the joint design and application. The time taken to reach this threshold may be estimated.
Related papers
Author(s) : Ajay Taraiya, Peter Degenhart, Mark Boerakker
In PPXX, a technology was presented for the first time that could bi-axially orient polyolefin pipes. With this technology, it is possible to prepare pipes that have a performance far beyond the standard ones. One approach to achieving this performance is via a continuous in-line process. To optimize the in-line...
Author(s) : Chris Ampfer, P.E., Harvey Svetlik, P.E.
The current polyethylene (PE) pipe bending limits (longitudinal and circumferential deflection) are based on a circumferential (tangential) strain tolerance limit of approximately 1%. Research in the late 1970’s using constant tensile strain focused on what strain can be imposed on HDPE by bending and not have it...
Author(s) : James F. Mason, Akshay Ponda, Hermann van Laak, Tobias Bauer
The long-term strength of unplasticized polyamide 12 (PA-U12) has been characterized using standard methods for plastic pressure pipe during the qualification process for use in buried piping systems for natural gas delivery operating at low ambient temperatures, usually less than 20 to 30°C at pressures...
Author(s) : Dr. Michael Pluimer, Sara Stone
The Notched Constant Ligament Stress test (NCLS test, ASTM F2136)[1] is a test method that measures the slow crack growth in High Density Polyethylene. The NCLS test requires a notch on all test specimens to act as a stress concentration at that point so crack propagation can be easily predicted and studied. In...
Author(s) : Norbert Jansen
A practical requirement of temperature resistance of minimum 50 years at 70°C was established for the extra high voltage (EHV) corridor projects in Germany. Experts have debated what tests are best suited to prove the suitability of a pipe resin for cable protection pipes which may be installed hastily and under...
Author(s) : Michael Pluimer, Christian Herrild, Patrick Vibien
With enhanced interest in a circular economy and the potential use of recycled HDPE within HDPE conduit, a research project was undertaken to investigate the necessary technical requirements when using recycled HDPE. High Density Polyethylene (HDPE) conduit is a durable product designed to protect cables...
Author(s) : Carine Lacroix, Philippe Louvel, Danielle Mark, Dominique Gueugnaut
A test program was carried out on two Polyamide resins, Polyamide 11 (PA11) and Polyamide 12 (PA12), both certified for gas networks. Polyamide’s advantage lies in its implementation, similar to that of polyethylene, and its properties allowing it to operate at up to 18 bar for gas, all other conditions being equal....
Author(s) : Jay Parvez, Richard Nichols
All thermoplastic and thermoset pipes must consider the impacts of cyclic loading on overall performance. Since its first use, PVC pipes have been tested for its resilience to such loading. As testing evolved over time, the method to determine cyclic capacity for gasketed PVC pipes has improved. Previously, the...
Author(s) : Peter Youssef, Sultan Alkendi, Hussein Basha
Bahr El-Baqar Water Treatment Plant, produces 2 billion m3 per year, introduces a sustainable solution for environmental pollution recovery and irrigation water source (via recycling the water of Bahr El- Baqar drain); whereas it protects the environment and generates water to support the cultivation of 4000 km2 in...
Author(s) : J. Lahoz
An investigation project was launched in 2020 to clarify the relationships between the processing conditions and the design lifetime of PVC-U 250 pipes. Ca/Zn stabilized pressure pipes were extruded with different processing temperatures and characterized by their DSC B-onset temperature and degree of gelation. Their...
Author(s) : Suleyman Deveci, Aisha Khaleel, Birkan Eryigit
Short and long term hydrostatic pressure resistance of plastic pipes are measured according to ISO 1167, by applying an internal pressure that is calculated for the target hoop stress considering outer diameter and wall thickness of the pipe samples. Due to the nature of the extrusion process, wall thickness...
Author(s) : Harry Mavridis
Demand for thick-wall (i.e., greater than about 2”-3” in thickness[15] ) HDPE pressure pipe is increasing worldwide for water, mining and oil & gas gathering applications. Resin producers have been developing HDPE resins that combine performance requirements (PE4710 or PE100) with processability attributes needed for...
Author(s) : Jennifer Ravereau, Catherine GIORNI, Benjamin RABAUD, Frederic Mohier, Mehdi Ahmadi
Pipe installation and renewal are critical for network management and extension both in terms of cost and of logistics for installation. Plastic materials, as polyethylene, are constantly evolving to offer additional benefits (chemical resistance improvement, mechanical resistance, innovative functionalities)....
Author(s) : Mario Messiha, Jessica Hinczica, Márton Bredàcs, Alwin Huisjes, Florian Arbeiter, Gerald Pinter
BSTRACT Engineering structures, such as operating plastic pipes, are often submitted to unexpected influences that may shorten their lifetime. An increasing understanding about the processes that govern these sudden failures has been attained in the last decades. This has led to a remarkable improvement of pipe...
Author(s) : A. Taraiya, P. Degenhart, M. Soliman, M. Boerakker, R. Handstanger, R. Kleppinger
Since the introduction of polyolefins for pressure pipes, continuous improvements have been made to meet ever-higher demands on their performance and to expand their application window beyond their original scope, mostly based on new resin formulations. Today, we also continue to push the limit to provide better...
Author(s) : Chris Ampfer, Gene Palermo, Ernest & Oren Lever
This paper looks at the origin of the 10% allowable scratch depth rule for polyethylene (PE) pressure pipe developed in 1971 and research that has been performed over the years since its inception to determine the validity of this rule. The 10% rule has been used by natural gas pipeline operators since the 1970’s to...
Author(s) : Anja Armani, Helmut Zanzinger
PE-pipes are used in applications at temperatures higher than 40°C and long service lives like drainage pipes in landfill basal lining systems, drainage pipes in tunnels with high cover heights, geothermal applications, power plant technology, mining, underground cable protection pipes for power lines for...
Author(s) : Bruce Mowry, PhD, P.E., Brian Dorwart, P.G., P.E., David Mancini, Bryan Fletcher, Roger Williams, P.E., Rene Brito, EIT, Arnelio Alfonso, P.E .
The City of Miami Beach owns and operates a 54-inch sanitary sewage PCCP force main (FM) that was built in 1977. This FM is the only transmission pipeline for conveying about 22 million gallons per day (MGD) of raw sewage to the wastewater treatment plant. In 2012, the City identified structural deficiencies in the...
Author(s) : Dominique GUEUGNAUT, Pascal AUSSANT, Romuald BOUAFFRE, Myriam BECHROURI
Concerns regarding the environment and sustainable development have revived interest in the reprocessing and re-use of polymer materials from manufactured objects that have reached the end of their operating life. Within this framework, formal professional agreements have been put in place at global level under the...
Author(s) : James F. Mason, Akshay Ponda, Hermann van Laak, Buc Slay
The effects of liquid hydrocarbons on long term strength of pipe grade thermoplastic resins is an important consideration when designing pressure pipe for use in the oil and gas industry. There is an extensive body of work going back several decades descri bing these effects for pipe grade polyethylenes, and all...
Members of the Association
