Technical Basis for Proposed Revisions to ASME Section III Code Case N-891 on Maximum Allowable Indentation Depths in HDPE Pipe to Extend Applicability to PENT Ratings Up to 10,000 Hours

2020 ◽  
Author(s):  
Douglas Scarth ◽  
Prabhat Krishnaswamy ◽  
Phillip Rush ◽  
Douglas Munson
Keyword(s):  
High Density Polyethylene ◽  
Large Diameter ◽  
Surface Conditions ◽  
Test Conditions ◽  
Hdpe Pipe ◽  
Piping Systems ◽  
Current Maximum ◽  
Higher Temperature ◽  
Technical Basis ◽  
Hdpe Pipes

Abstract Mandatory Appendix XXVI of Section III of the ASME B&PV Code contains rules for the construction of Class 3 pressure piping systems comprised of PE4710 High Density Polyethylene (HDPE) with a minimum Pennsylvania Notched Test (PENT) rating of 2,000 hours. Appendix XXVI contains acceptance standards for the maximum allowable depths of gouges, cuts or other surface conditions that are characterized as indentations. The acceptance standards are very conservative, in particular for large diameter HDPE pipes. Less restrictive maximum allowable indentation depths for PE4710 HDPE pipes with a minimum PENT rating of 2,000 hours were previously developed based on analyses of tests on HDPE pipes containing scratches. These less restrictive maximum allowable indentation depths were published in the ASME Section III Code Case N-891 as an alternative to the acceptance standards in Appendix XXVI. The PENT rating of PE4710 HDPE material can significantly exceed 2,000 hours, and the current maximum allowable indentation depths in Code Case N-891 are overly-restrictive for the higher PENT ratings. Maximum allowable indentation depths for PENT ratings up to 10,000 hours have been developed, and are proposed to be implemented into a revision of Code Case N-891 and Appendix XXVI. The technical basis for the maximum allowable indentation depths for these higher PENT ratings is provided in this paper. The proposed revisions to Code Case N-891 include a provision to permit use of results from accelerated PENT testing at a higher temperature and stress level than standard PENT test conditions. The technical basis for the use of results from accelerated PENT testing is also provided in this paper.

Technical Basis for Maximum Allowable Indentation Depths in HDPE Pipes for Proposed ASME Section III Code Case on Alternative Requirements to Appendix XXVI for Inspection and Repair

2019 ◽  
Author(s):  
Douglas Scarth ◽  
Prabhat Krishnaswamy ◽  
Phillip Rush ◽  
Douglas Munson
Keyword(s):  
High Density Polyethylene ◽  
Large Diameter ◽  
Cooling Water ◽  
Water Systems ◽  
Parent Material ◽  
Surface Conditions ◽  
Service Water ◽  
Piping Systems ◽  
Technical Basis ◽  
Hdpe Pipes

Abstract Mandatory Appendix XXVI of Section III of the ASME B&PV Code contains rules for the construction of Class 3 polyethylene pressure piping systems. The scope is limited to buried portions of Class 3 service water or buried portions of Class 3 cooling water systems, consisting of PE4710 High Density Polyethylene (HDPE) materials. The minimum Pennsylvania Notched Test (PENT) rating for the HDPE material is 2,000 hours. Appendix XXVI contains acceptance standards for the maximum allowable depths of gouges, cuts or other surface conditions that are characterized as indentations. The acceptance standards are considered to be very restrictive, in particular for large diameter HDPE pipes. Less restrictive maximum allowable indentation depths for pipes with a minimum PENT rating of 2,000 hours were developed based on use of results from tests performed on pressurized HDPE pipes containing flaws in the parent material. These maximum allowable indentation depths were implemented into the new Section III Code Case N-891 on alternative requirements to Appendix XXVI for inspection and repair. The technical basis for the maximum allowable indentation depths is described in this paper.

Modern Bimodal High Density Polyethylene for the Nuclear Power Plant Piping System

2009 ◽  
Author(s):  
Adel N. Haddad
Keyword(s):  
High Density Polyethylene ◽  
Nuclear Power ◽  
Large Diameter ◽  
Water System ◽  
High Density ◽  
Nuclear Industry ◽  
Piping System ◽  
Service Water ◽  
Hdpe Pipe ◽  
Related Service

Originally introduced in the 1990s, bimodal HDPE, pipe resins are still finding new niches today, including even nuclear power plants. HDPE pipe grades are used to make strong, corrosion resistant and durable pipes. High density polyethylene, PE 4710, is the material of choice of the nuclear industry for the Safety Related Service Water System. This grade of polymer is characterized by a Hydrostatic Design Basis (HDB) of 1600 psi at 73 °F and 1000 psi at 140 °F. Additionally bimodal high density PE 4710 grades display >2000 hours slow crack growth resistance, or PENT. HD PE 4710 grades are easy to extrude into large diameter pipes; fabricate into fitting and mitered elbows and install in industrial settings. The scope of this paper is to describe the bimodal technology which produces HDPE pipe grade polymer; the USA practices of post reactor melt blending of natural resin compound with black masterbatch; and the attributes of such compound and its conformance to the nuclear industry’s Safety Related Service Water System.

scholarly journals Modeling benzene permeation through drinking water high density polyethylene (HDPE) pipes

2015 ◽  
Vol 13 (3) ◽  
pp. 758-772 ◽  
Author(s):  
Feng Mao ◽  
Say Kee Ong ◽  
James A. Gaunt
Keyword(s):  
Drinking Water ◽  
High Density Polyethylene ◽  
Distribution Systems ◽  
Water Distribution ◽  
Large Diameter ◽  
Small Diameter ◽  
High Density ◽  
Ethyl Benzene ◽  
Constant Input ◽  
Hdpe Pipes

Organic compounds such as benzene, toluene, ethyl benzene and o-, m-, and p-xylene from contaminated soil and groundwater may permeate through thermoplastic pipes which are used for the conveyance of drinking water in water distribution systems. In this study, permeation parameters of benzene in 25 mm (1 inch) standard inside dimension ratio (SIDR) 9 high density polyethylene (HDPE) pipes were estimated by fitting the measured data to a permeation model based on a combination of equilibrium partitioning and Fick's diffusion. For bulk concentrations between 6.0 and 67.5 mg/L in soil pore water, the concentration-dependent diffusion coefficients of benzene were found to range from 2.0 × 10−9 to 2.8 × 10−9cm2/s while the solubility coefficient was determined to be 23.7. The simulated permeation curves of benzene for SIDR 9 and SIDR 7 series of HDPE pipes indicated that small diameter pipes were more vulnerable to permeation of benzene than large diameter pipes, and the breakthrough of benzene into the HDPE pipe was retarded and the corresponding permeation flux decreased with an increase of the pipe thickness. HDPE pipes exposed to an instantaneous plume exhibited distinguishable permeation characteristics from those exposed to a continuous source with a constant input. The properties of aquifer such as dispersion coefficients (DL) also influenced the permeation behavior of benzene through HDPE pipes.

Thermal failure mechanism of fiber ropes when bent over sheaves

2018 ◽  
Vol 89 (7) ◽  
pp. 1215-1223
Author(s):  
Fanggang Ning ◽  
Xiaoru Li ◽  
Nick O Hear ◽  
Rong Zhou ◽  
Chuan Shi ◽  
...  
Keyword(s):  
Failure Mechanism ◽  
Thermal Damage ◽  
Synthetic Fiber ◽  
Heat Accumulation ◽  
Thermal Failure ◽  
Synthetic Fibers ◽  
Test Conditions ◽  
Bending Process ◽  
Higher Temperature ◽  
Bending Failure

Thermal damage is an important failure mechanism that affects the bending failure of fiber ropes. This is relevant because synthetic fibers often have a relatively low melting point and low thermal conductivity. In cyclic bending over sheave (CBOS), the heat generated by friction and deformation is not conducted rapidly to the external environment, and the temperature of the rope core increases quickly. This higher temperature greatly reduces the mechanical properties of the fiber, thus accelerating the final rope failure. In this paper, evidence of thermal damage in the bending process of a braided synthetic fiber rope is given. The test conditions inducing thermal damage are discussed, including stress level, bending frequency and diameter ratio. The reasons for the heat generation and the dynamic process of heat accumulation inside the rope during CBOS are also discussed. This study aims to provide theoretical and experimental guidance for the design and use of fiber rope.

Determination of Updated Fatigue Properties of PE 4710 Cell Classification 445574C High Density Polyethylene

2014 ◽  
Author(s):  
Timothy M. Adams ◽  
Shawn Nickholds ◽  
Douglas Munson ◽  
Jeffery Andrasik
Keyword(s):  
Carbon Steel ◽  
Pressure Vessel ◽  
High Density Polyethylene ◽  
Nuclear Power ◽  
Fatigue Testing ◽  
High Density ◽  
Labor Costs ◽  
Cell Classification ◽  
Service Water ◽  
Hdpe Pipe

For corroded piping in low temperature systems, such as service water systems in nuclear power plants, replacement of carbon steel piping with high density polyethylene (HDPE) is a cost-effective solution. Polyethylene pipe can be installed at much lower labor costs that carbon steel pipe and HDPE pipe has a much greater resistance to corrosion. The ASME Boiler and Pressure Vessel Code, Section III, Division 1 currently permits the use of non-metallic piping in buried safety Class 3 piping systems. Additionally, HDPE pipe has been successfully used in non-safety-related systems in nuclear power facilities and is commonly used in other industries such as water mains and natural gas pipelines. This report presents the results of updated fatigue testing of PE 4710 cell classification 445574C pipe compliant with the specific Code requirements. This information was developed to support and provide a strong technical basis for material properties of HDPE pipe for use in ASME Boiler and Pressure Vessel Code, Section III New Construction and Section XI repair or replacement activities. The data may also be useful for applications of HDPE pipe in commercial electric power generation facilities and chemical, process and waste water plants via its possible use in the B31 series piping codes. The report provides fatigue data in the form of Code S-N curves for fusion butt joints in PE 4710 cell classification 445574C HDPE pipe.

Slow Crack Growth Resistance of Parent and Joint Materials From PE4710 Piping for Safety-Related Nuclear Power Plant Piping

2011 ◽  
Author(s):  
S. Kalyanam ◽  
D.-J. Shim ◽  
P. Krishnaswamy ◽  
Y. Hioe
Keyword(s):  
Crack Growth ◽  
Nuclear Power ◽  
Power Plants ◽  
Slow Crack Growth ◽  
Nuclear Industry ◽  
Pipe Material ◽  
Service Water ◽  
Hdpe Pipe ◽  
Pipe Materials ◽  
Hdpe Pipes

HDPE pipes are considered by the nuclear industry as a potential replacement option to currently employed metallic piping for service-water applications. The pipes operate under high temperatures and pressures. Hence HDPE pipes are being evaluated from perspective of design, operation, and service life requirements before routine installation in nuclear power plants. Various articles of the ASME Code Case N-755 consider the different aspects related to material performance, design, fabrication, and examination of HDPE materials. Amongst them, the material resistance (part of Article 2000) to the slow crack growth (SCG) from flaws/cracks present in HDPE pipe materials is an important concern. Experimental investigations have revealed that there is a marked difference (almost three orders less) in the time to failure when the notch/flaw is in the butt-fusion joint, as opposed to when the notch/flaw is located in the parent HDPE material. As part of ongoing studies, the material resistance to SCG was investigated earlier for unimodal materials. The current study investigated the SCG in parent and butt-fusion joint materials of bimodal HDPE (PE4710) pipe materials acquired from two different manufacturers. The various stages of the specimen deformation and failure during the creep test are characterized. Detailed photographs of the specimen side-surface were used to monitor the specimen damage accumulation and SCG. The SCG was tested using a large specimen (large creep frame) as well as using a smaller size specimen (PENT frame) and the results were compared. Further, the effect of polymer orientation or microstructure in the bimodal HDPE pipe on the SCG was studied using specimens with axial and circumferential notch orientations in the parent pipe material.

scholarly journals Friction Measurement in MEMS Using a New Test Structure

1999 ◽  
Vol 605 ◽  
Author(s):  
B.T. Crozier ◽  
M.P. de Boer ◽  
J.M. Redmond ◽  
D.F. Bahr ◽  
T.A. Michalske
Keyword(s):  
Steady State ◽  
Normal Pressure ◽  
Test Structure ◽  
Friction Measurement ◽  
Self Assembled Monolayer ◽  
Environmental Loading ◽  
Friction Coefficients ◽  
Surface Conditions ◽  
Lubricating Film ◽  
Test Conditions

AbstractA MEMS test structure capable of measuring friction between polysilicon surfaces under a variety of test conditions has been refined from previous designs. The device is applied here to measuring friction coefficients of polysilicon surfaces under different environmental, loading, and surface conditions. Two methods for qualitatively comparing friction coefficients (µ) using the device are presented. Samples that have been coated with a self-assembled monolayer of the lubricating film perfluorinated-decyltrichlorosilane (PFTS) have a coefficient of friction that is approximately one-half that of samples dried using super-critical CO2 (SCCO2) drying. Qualitative results indicate that µ is independent of normal pressure. Wear is shown to increase µ for both supercritically dried samples and PFTS coated samples, though the mechanisms appear to be different. Super critically dried surfaces appear to degrade continuously with increased wear cycles, while PFTS coated samples reach a steady state friction value after about 105 cycles.

scholarly journals Deformation Analysis of Large Diameter Monopiles of Offshore Wind Turbines under Scour

2020 ◽  
Vol 10 (21) ◽  
pp. 7579
Author(s):  
Zhaoyao Wang ◽  
Ruigeng Hu ◽  
Hao Leng ◽  
Hongjun Liu ◽  
Yifan Bai ◽  
...  
Keyword(s):  
Wind Turbines ◽  
Wind Farm ◽  
Large Diameter ◽  
Horizontal Displacement ◽  
Local Scour ◽  
Offshore Wind ◽  
Deformation Analysis ◽  
Pile Head ◽  
Offshore Wind Turbines ◽  
Test Conditions

The displacement of monopile supporting offshore wind turbines needs to be strictly controlled, and the influence of local scour can not be ignored. Using p–y curves to simulate the pile–soil interaction and the finite difference method to calculate iteratively, a numerical frame for analysis of lateral loaded pile was discussed and then verified. On the basis of the field data from Dafeng Offshore Wind Farm in Jiangsu Province, the local scour characteristics of large diameter monopile were concluded, and a new method of considering scour effect applicable to large diameter monopile was put forward. The results show that, for scour of large diameter monopiles, there was no obvious scour pit, but local erosion and deposition. Under the test conditions, the displacement errors between the proposed and traditional method were 46.4%. By the proposed method, the p–y curves of monopile considering the scour effect were obtained through ABAQUS, and the deformation of large diameter monopile under scour was analyzed by the proposed frame. The results show that, with the increase of scour depth, the horizontal displacement of the pile head increases nonlinearly, the depth of rotation point moves downward, and both of the changes are related to the load level. Under the test conditions, the horizontal displacement of the pile head after scour could reach 1.4~3.6 times of that before scour. Finally, for different pile parameters, the pile head displacement was compared, and further, the susceptibility to scour was quantified by a proposed concept of scour sensitivity. The analysis indicates that increasing pile length is a more reasonable way than pile diameter and wall thickness to limit the scour effect on the displacement of large diameter pile.

scholarly journals Influence of Backfill Compaction on Mechanical Characteristics of High-Density Polyethylene Double-Wall Corrugated Pipelines

2019 ◽  
Vol 2019 ◽  
pp. 1-24 ◽  
Author(s):  
Hongyuan Fang ◽  
Peiling Tan ◽  
Bin Li ◽  
Kangjian Yang ◽  
Yunhui Zhang
Keyword(s):  
Finite Element ◽  
High Density Polyethylene ◽  
Three Dimensional ◽  
Local Buckling ◽  
Element Model ◽  
High Density ◽  
Model Matching ◽  
Exterior Wall ◽  
Finite Element Software ◽  
Hdpe Pipe

For flexible pipelines, the influence of backfill compaction on the deformation of the pipe has always been the focus of researchers. Through the finite element software, a three-dimensional soil model matching the exterior wall corrugation of the high-density polyethylene pipe was skillfully established, and the “real” finite element model of pipe-soil interaction verified the accuracy through field test. Based on the model, the strain distribution at any position of the buried HDPE pipe can be obtained. Changing the location and extent of the loose backfill, the strain and radial displacement distributions of the interior and exterior walls of the HDPE pipe under different backfill conditions when external load applied to the foundation were analyzed, and the dangerous parts of the pipe where local buckling and fracture may occur were identified. It is pointed out that when the backfill is loose, near the interface between the backfill loose region and the well-compacted region, the maximum circumferential strain occurs frequently, the exterior wall strain is more likely to increase greatly on the region near crown or invert, the interior wall strains increase in amplitude at springline, and the location of the loose region has a greater influence on the strain of the pipe than the size of the loose area.

Sign in / Sign up

Export Citation Format

Share Document