Our site uses cookies necessary for its proper functioning. To improve your experience, other cookies may be used: you can choose to disable them. This can be changed at any time via the Cookies link at the bottom of the page.


The Evolution of Elastomeric Joints in Plastic Pipe Systems and the use of Long Term Stress Relaxation Testing to Predict Service Life

 

Julian West

Papers # 2018 Las-Vegas

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 keywords : Stress Relaxation, Contact Pressure, Force Decay, Long Term Durability.
Please note that the whole article content is available on PPCA website only

Related papers

2021 Amsterdam : A NEW GENERATION OF HIGH PERFORMANCE BIAXIALLY ORIENTED POLYETHYLENE AND POLYPROPYLENE PRESSURE PIPES

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...

2021 Amsterdam : ALLOWABLE SCRATCH DEPTH HISTORY & RECOMMENDATIONS FOR PE PRESSURE PIPE

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...

2021 Amsterdam : CONFIRMATION OF LONG SERVICE LIVES OF PE-PIPES UNDER HIGHER TEMPERATURES APPLYING CONVENTIONAL OVEN TESTS AND MODERN HIGH-PRESSURE AUTOCLAVE TESTS

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...

2021 Amsterdam : DEVELOPMENT OF A RAPID AND INNOVATIVE IN-FACTORY PROCEDURE FOR TESTING THE PERFORMANCES OF PE PIPES CONTAINING VARIOUS PROPORTIONS OF RECYCLED POLYMER MATERIAL

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...

2021 Amsterdam : EXPERIMENTAL DETERMINATION OF THE EFFECTS OF LIQUID HYDROCARBONS ON THE LONG-TERM CREEP RUPTURE PROPERTIES OF PRESSURE PIPE GRADE UNPLASTICIZED POLYAMIDE-12

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...

2021 Amsterdam : MOBILE EXTRUSION TECHNOLOGY - A CASE STUDY USING INNOVATIVE MEANS OF ASSURING HDPE PIPE SUPPLY (IN BOTH THE PERMIAN BASIN OF WEST TEXAS AND THE MINING REGION OF CENTRAL FLORIDA)

Author(s) : White G. Jee, Wes Long, Marcello Russo

In 2018, the North American HDPE pressure pipe market experienced unprecedented demand and growth especially in the region of the Permian basin in west Texas. 1 As aninnovative means of increasing HDPE pipe supply in this region, the first modular mobile extrusion plant was moved to Pecos, TX. Using custom designed...

2021 Amsterdam : MODIFIED PLAIN STRAIN GROOVED TENSILE TEST TO EVALUATE LARGE DIAMETER PE PIPES

Author(s) : Thomas R. Kratochvilla, Patrick Grünbeck, Christoph Bruckner, Raimund Eremiasch, Harald Wilhelm, Mario Vukelja

In the last decades pipe dimensions of extruded PE pipes have reached new orders of size. Today, PE pipes with outer diameters of up to DN/OD 3500 mm are produced and used for pressure pipe applications like seawater intake/discharge, outfall, sewage and industrial process piping systems. To test the long-term...

2021 Amsterdam : MULTILAYER POLYMER PIPES – THE INFLUENCE OF RESIDUAL STRESS ON FATIGUE LIFETIME

Author(s) : Lukas Travnicek, Pavel Hutar, Jan Poduska, Andreas Frank, Florian Arbeiter, Jaroslav Kucera, Jiri Sadilek, Gerald Pinter, Lubos Nahlik

The application of recycled material in pressure piping systems has been considered lately – it was suggested, that the recycled polyethylene could be used as a part of a multilayer pipe together with virgin material. This type of pressure pipes is not availableon the market yet, so their properties can be only...

2021 Amsterdam : NEW CHALLENGING APPLICATION AS USED PEAT LAND HIGH PERFORMANCE PE-SGF PIPELINE SYSTEM FOR INTERNAL PRESSURE APPLICATION AS LARGE DIAMETER

Author(s) : Kensei INOUE, Mitsuaki TOKIYOSHI, Joji HINOBAYASHI, Takeshi KARINO, Toshinori KAWABATA, Takashi KURIYAMA

As the worldwide problems are over-population, unusual weather like as localized heavy rain and climate change. Against those problem, it has to need new projects to make a new agricultural field, drainage pipeline system and to spread the new underground irrigation system at peat land whereas spots of about 2 million...

2021 Amsterdam : ONLINE ENGINEERING TOOLS FOR DESIGN AND FIELD ENGINEERS

Author(s) : Dustin Langston

The design and installation of polyethylene systems can be complex, specifically due to the many applications and environmental conditions that surround those systems. Online design tools have been developed to address this complexity and the various factors that must be considered. These online tools used widely in...

2021 Amsterdam : PRESSURE PIPELINE MADE OF HDPE – DETERMINATION OF REMAINING LIFETIME AFTER 47 YEARS OF OPERATION IN LAKE OSSIACH (CARINTHIA, AUSTRIA)

Author(s) : Ulrich Schulte, Dr. -Ing. Joachim Hessel

In order to protect the Austrian lakes effectively against the discharge of effluent, a 13 km long pressure pipeline made of high density polyethylene was laid on the bottom of Lake Ossiach back in 1971. The DN355 to DN200 pipes were produced from a first generation HDPE-compound. The classification would have been...

2021 Amsterdam : TESTING AND APPLICATION OF POLYETHYLENE PRESSURE PIPING FOR NUCLEAR POWER IN CHINA

Author(s) : Hua Ye, Sun Jin, Wei Ruoqi

As a safe, clean, low-carbon and reliable energy source, nuclear power, together with hydropower and coal power, constitutes the three pillars of the world's energy supply and play an important role in the world's energy structure.With the strong support of national policies, China's nuclear energy has entered a new...

2021 Amsterdam : TESTING SPOOLABLE REINFORCED FLEXIBLE PIPES AND LINER MATERIAL FOR HIGH-PRESSURE HYDROGEN TRANSPORT

Author(s) : Sjoerd Jansma, Peter Cloos, Ernst van der Stok

This paper describes two different test methods used to determine the permeation rate of hydrogen through a reinforced thermoplastic pipe (RTP) system with a HDPE liner pipe and a gas-tight layer at a pressure of 42 bar(g) hydrogen and ambient temperature. One method involThe results of the aforementioned tests...

2018 Las-Vegas : C-PVC-O, pushing limits beyond in molecular orientation

Author(s) : Ignacio Muñoz

During the last years PVC-O has become a popular product in pipe business due to the huge improvements of mechanical properties of PVC after orientation. At the same time, CPVC has become an important choice for hot water conduits in in-house applications. Molecor has started a research program to evaluate the...

2018 Las-Vegas : Effect of eccentricity on the measurement of hydrostatic pressure resistance of plastic pipes

Author(s) : Suleyman Deveci, Birkan Eryigit, Senthil K. Kaliappan

The effect of eccentricity on the failure time of pipes under hydrostatic pressure test has a significant magnitude that it can easily mislead the evaluation of pipes according to requirement of ISO 4427-2. Therefore, authors propose a maximum relative eccentricity limit of 0.015, even lower, for pipes being tested...

2018 Las-Vegas : Field test of Glass fiber reinforced polyethylene pipe system at soften ground

Author(s) : Mitsuaki TOKIYOSHI, Gentaro TAKAHARA, Joji HINOBAYASHI, Toshinori KAWABATA, Takashi KURIYAMA

Glass fiber reinforced polyethylene pipes and fittings are controlled for bending characteristics (Strength and stiffness) for vertical and axial directions of pipe by spiral cross winding method. Generally, to use this method, it takes much stronger for vertical strength than axials cause of extruded direction,...

2018 Las-Vegas : Large diameter spiral wound pressure pipes

Author(s) : Bülent Kuzkaya

Spiral wound pipes are becoming more and more important in larger diameter HDPE pipe production technology. The spiral wound structured wall pipes with profiles are already well known and used for several low or non-pressure pipe applications. This paper shows that spiral wound pressure pipes can fulfill the...

2018 Las-Vegas : Large pressure pipe system – Fully PE100

Author(s) : Sverre Tragethon, Martin Andersson

Global mega trends push for investments in sewage treatment capacity & efficiency. A trend is to go for central regional treatment sites, typically remotely located from dense populated cities. This calls for high capacity pressure sewage transmission pipelines. Reliable operation is of course of paramount importance...

2018 Las-Vegas : Study on the resistance to external pressure test methods of plastic inspection chambers

Author(s) : Zhang Wei, Wei Ruoqi, Zhou Minghong, Zhou Mingwei,

This article gives a brief introduction of plastic inspection chambers in China. It focuses on the formulation of China's national standard for plastic inspection chambers and conducts the theoretical analysis and data validation of the key technical metrics in the standard for the following three tests: the...

2016 Berlin : Bi-oriented PVC extrusion: stretching pipe performance

Author(s) : André Nijland

Bi-oriented PVC (PVC-O) pipes are increasingly installed on a worldwide basis for drinking water applications. This is due to the outstanding mechanical properties of PVC-O pipes, such as high strength and high ductility. Furthermore bi-oriented PVC pipes are light weight, flexible and have a low carbon footprint and...

Members of the Association

BOREALISBOROUGEFormosa Plastics CorporationHanwha TotalEnergiesINEOS O&PIRPCKazanorgsintez PJSCKorea Petrochemical IND. Co., LTD (KPIC)LyondellBasellPetroChina Dushanzi Petrochemical CompanyPRIME POLYMERSABICSCG Chemicals & Thai PolyethyleneSinopecTASNEE
TOP