Installation Errors in Polyethylene Pipe for Natural Gas Service: Recent Case Histories by the National Transportation Safety Board (NTSB)

2020 ◽  
Author(s):  
Frank Zakar
Keyword(s):  
Natural Gas ◽  
Service Life ◽  
Material Properties ◽  
Best Practice ◽  
Transportation Safety ◽  
Gas Leakage ◽  
Polyethylene Pipes ◽  
Gas Leak ◽  
Mechanical Methods ◽  
National Transportation Safety Board

Abstract The National Transportation Safety Board investigated numerous accidents involving the release of natural gas from polyethylene pipelines. The industry manufactures polyethylene pipes and fittings in many shapes and they can be installed/joined in a variety of ways. New grades with improved material properties, such as high-density polyethylene (HDPE) and ultra-high-molecular-weight polyethylene (UHMWPE) have been introduced that show improved material properties compared to their medium-density polyethylene (MDPE) predecessors. However, improved material properties by themselves do not guarantee extended service life of an installed pipe or fitting. Simple errors, whether unintentional, unknown, or unaware by the installer, can lead to a gas leak and possibly a serious accident that causes injury or loss of life. These errors can significantly reduce the service life of a pipe or fitting. The NTSB Materials Laboratory examined several polyethylene service tees that were involved in an accident as a result of a natural gas leak. Examples of gas leakage resulting from failure to follow best practice at installation will be mentioned. Certain service tee assemblies are joined to pipe segments by mechanical methods while others are joined by fusion methods, such as heat fusion or electrofusion process. An example is cited where a manufacturer of a mechanical tapping tee made several versions of the same design that required specific installation instructions that were different from their predecessors. When several versions of the same tee assembly are manufactured by the same company, one should be aware of identifiable features that differentiate one version from another and then carefully use installation instructions that apply to the model that will be installed. Another example is cited where a service tee that was joined by the heat fusion process had been contaminated prior to bonding. Learning from mistakes that are made during installation, through examples, provides a foundation from which we can correct our procedures and avoid repeating the same mistakes in the future.

Assessment of Gas Leak Detection Techniques in Natural Gas Infrastructure: A Review

2021 ◽  
Author(s):  
Dulu Appah ◽  
Victor Aimikhe ◽  
Wilfred Okologume
Keyword(s):  
Natural Gas ◽  
Value Chain ◽  
Economic Loss ◽  
Leak Detection ◽  
Analytical Models ◽  
Detection Techniques ◽  
Gas Leakage ◽  
Gas Leak ◽  
Operational Activities ◽  
Gas Leaks

Abstract The undetected gas leak, also referred to as fugitive gas emissions, are produced from natural gas infrastructure during operational activities. If not monitored, this undetected gas leakage can lead to undesirable economic loss of natural gas from installed infrastructures and are often accompanied by toxic air pollutants that typically pose safety and public health concerns. The efficient quantification of gas leaks from natural gas infrastructure value chain is still largely inadequate. Several studies have repeatedly opined that the actual rate of leaks from natural gas infrastructure is often higher than the documented estimates. The latter is largely dependent on assumptions that rely on inadequate data. This study reviewed most of the existing methods implemented to detect and quantify gas leaks in natural gas infrastructure by assessing the techniques based on the amount of leak detected compared to the amount of gas produced from such facilities. The study illustrates both the problem of methane leakage and the opportunities for instantaneous reduction from natural gas transmission facilities. Furthermore, this review provides a detailed account of the various analytical models and instrumentation-based research performed to identify and quantify gas leak detection. The study opined that the uncertainties associated with efficient quantification of natural gas leak rates demonstrate the need for innovative approaches or processes to identify and quantify leak rates from natural gas infrastructure.

Comparison of material properties in butt welds of used and unused polyethylene pipes for natural gas distribution

energyo ◽  
2019 ◽  
Author(s):  
Fatima Zohra Talhi ◽  
Mohamed Tahar Benaniba ◽  
Naima Belhaneche-Bensemra ◽  
Valérie Massardier
Keyword(s):  
Natural Gas ◽  
Material Properties ◽  
Gas Distribution ◽  
Butt Welds ◽  
Polyethylene Pipes

scholarly journals Continuous CH₄ and δ¹³CH₄ Measurements in London Demonstrate Under-Reported Natural Gas Leakage

2021 ◽  
Author(s):  
Eric Saboya ◽  
Giulia Zazzeri ◽  
Heather Graven ◽  
Alistair J. Manning ◽  
Sylvia Englund Michel
Keyword(s):  
Natural Gas ◽  
Gas Leakage

Chemical Deliquification of Unconventional Gas Wells

2014 ◽  
Author(s):  
K.. Francis-LaCroix ◽  
D.. Seetaram
Keyword(s):  
Natural Gas ◽  
Best Practice ◽  
Oil And Gas ◽  
Large Deviation ◽  
Cost Effective ◽  
Gas Production ◽  
Lessons Learned ◽  
Offshore Platforms ◽  
Gas Wells ◽  
Current Production

Abstract Trinidad and Tobago offshore platforms have been producing oil and natural gas for over a century. Current production of over 1500 Bcf of natural gas per year (Administration, 2013) is due to extensive reserves in oil and gas. More than eighteen of these wells are high-producing wells, producing in excess of 150 MMcf per day. Due to their large production rates, these wells utilize unconventionally large tubulars 5- and 7-in. Furthermore, as is inherent with producing gas, there are many challenges with the production. One major challenge occurs when wells become liquid loaded. As gas wells age, they produce more liquids, namely brine and condensate. Depending on flow conditions, the produced liquids can accumulate and induce a hydrostatic head pressure that is too high to be overcome by the flowing gas rates. Applying surfactants that generate foam can facilitate the unloading of these wells and restore gas production. Although the foaming process is very cost effective, its application to high-producing gas wells in Trinidad has always been problematic for the following reasons: Some of these producers are horizontal wells, or wells with large deviation angles.They were completed without pre-installed capillary strings.They are completed with large tubing diameters (5.75 in., 7 in.). Recognizing that the above three factors posed challenges to successful foam applications, major emphasis and research was directed toward this endeavor to realize the buried revenue, i.e., the recovery of the well's potential to produce natural gas. This research can also lead to the application of learnings from the first success to develop treatment for additional wells, which translates to a revenue boost to the client and the Trinidad economy. Successful treatments can also be used as correlations to establish an industry best practice for the treatment of similarly completed wells. This paper will highlight the successes realized from the treatment of three wells. It will also highlight the anomalies encountered during the treatment process, as well as the lessons learned from this treatment.

scholarly journals Assessment of Cascading Accidents of Frostbite, Fire, and Explosion Caused by Liquefied Natural Gas Leakage

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Chengjun Yue ◽  
Li Chen ◽  
Hengbo Xiang ◽  
Linfeng Xu ◽  
Shigang Yang ◽  
...  
Keyword(s):  
Heat Flux ◽  
Natural Gas ◽  
Fluid Dynamic ◽  
Liquefied Natural Gas ◽  
Toxic Substances ◽  
Origin And Evolution ◽  
Gas Leakage ◽  
Wind Speeds ◽  
Vapor Cloud ◽  
Computational Fluid Dynamic Software

Liquefied natural gas (LNG) leaks often lead to cascading accident disasters, including vapor cloud release, explosion, fire, and toxic gas release. The origin and evolution of each accidental disaster must be considered when assessing safety. This paper discusses the safety assessment project of an LNG gas storage station in Xuzhou, China. Multiple conceivable disasters due to the leakage of LNG storage tanks are simulated and analyzed using the computational fluid dynamic software FLACS. We studied different wind speeds interacting with the flammable vapor cloud area and creating frostbite in areas of low temperature. Diffusion simulations of vapor cloud explosion (VCE), thermal radiation, and the distribution of toxic substances were performed. The overpressure-impulse criterion was used to calculate the influence range of VCE. Heat flux, heat dose, and heat flux-heat dose criteria were used to calculate the safe distance for personnel in the event of fire. Based on the calculation results of the three latter criteria, this paper recommends using the heat flux criterion to evaluate fire accidents. The danger zone of each accident was compared. VCE accidents yielded the largest area.

Study on the Design of SMA Mixture on Expressway

2014 ◽  
Vol 496-500 ◽  
pp. 2582-2585
Author(s):  
Jian Ping Xu ◽  
Fu Ming Liu
Keyword(s):  
Service Life ◽  
Laboratory Test ◽  
Material Properties ◽  
Road Traffic ◽  
Jiangxi Province ◽  
Skid Resistance ◽  
Maintenance Costs ◽  
Modified Asphalt ◽  
Superior Surface ◽  
Structure Strength

The rapid growth of road traffic brings some requirements on driving comfort and safety, which include good smoothness, skid resistance and reduced noise of the pavement. SMA has adequate structure strength to reduce rutting and provide superior surface function of skid resistance. Modified asphalt as mixture binder, has considerable durability to ensure the service life with less maintenance costs. Associated with laboratory test and trial section, some suggestion and requirements are brought forward in this paper for the material properties and mixture design of SMA on the FuZhou-JiAn expressway in Jiangxi Province.

Progressive Collapse Evaluation for Historic Building Structures

2010 ◽  
Vol 133-134 ◽  
pp. 1225-1231 ◽  
Author(s):  
Feng Lin ◽  
Ying Wang ◽  
Xiang Lin Gu ◽  
Xin Yuan Zhao
Keyword(s):  
Service Life ◽  
Material Properties ◽  
Progressive Collapse ◽  
Failure Criteria ◽  
Seismic Action ◽  
Historic Buildings ◽  
Building Structures ◽  
Historic Building ◽  
Current Design ◽  
Alternate Path Method

Important historic buildings may be subjected to accidental loads during their service life. It is therefore necessary not only to evaluate their safety under traditional loads and seismic action (only in earthquake area), but also to evaluate the structural performance of resisting progressive collapse. For historic buildings, two aspects make them different from the modern buildings: the material properties are usually deteriorated to some extent, and the structural system/constructions may not meet the requirements of current design and construction codes. Considering such aspects, a method consisting of four steps to evaluate the performance of the historic buildings to resist progressive collapse is presented in this paper. Firstly, the building layout should be evaluated whether it can protect the occupants from the possible explosion. Secondly, geometrical information, structural constructions and the material properties are to be investigated in details. Thirdly, by means of tie force method and the alternate path method the performance of the structure is analyzed to resist progressive collapse. The load combinations used in the analysis are derived based on the expected service life of the structure. The failure criteria for the structural elements as well as the damage limits for the structure follow the provisions addressed in American Unified Facilities Criteria “Design of Structure to Resist Progressive Collapse” (UFC 4-023-03). Finally, based on the above information an overall evaluation is made for the probably structural retrofitting and strengthening. This method is illustrated with a case study of a steel frame historic building, namely the Bund 18 building, in Shanghai, China. Some suggestions for retrofitting and strengthening this building are also presented.

scholarly journals Perancangan Detektor Kebocoran Gas LPG Berbasis Arduino yang Terhubung dengan Smartphone

2021 ◽  
Vol 3 (1) ◽  
pp. 65
Author(s):  
Ade Mutaqin ◽  
Erwin Sitompul
Keyword(s):  
Gas Sensor ◽  
Early Warning ◽  
Leak Detector ◽  
Liquefied Petroleum Gas ◽  
Measurement Result ◽  
Gas Leakage ◽  
Gas Leak ◽  
High Level ◽  
Air Circulation

LPG (Liquefied Petroleum Gas) has become the fuel for cooking for most households in Indonesia. The use of LPG for cooking requires high level of caution, due to the danger that may arise from gas leakage. If the molecules of flammable LPG gas are present in the air at a certain concentration and there is a triggerring factor in the form of flame or sparks, explosion and fire may occur. To prevent disasters caused by a LPG gas leakage, the author proposed an Arduino-based LPG gas leak detector (GLD). The GLD is equipped with a MQ-2 gas sensor, capable of measuring the LPG concentration in air in units of parts per million (ppm). Based on the measurement result, the GLD provides an early warning of LPG leakage through 3 condition levels: Normal, Alert, and Danger. Each condition level is characterized by the activation of LED indicators, a miniature air circulation fan , and a buzzer. Alert warning is released when the sensor reads more than 400 ppm (2.05% of LPG Lower Explosive Level). Danger warning is given at 800 ppm (4.10% of LPG Lower Explosive Level) or higher reading. An HC-06 Bluetooth module creates a wireless connection between the GLD and a smartphone. Through an application created on Blynk platform, the smartphone can monitor the LPG concentration at a distance of 10 m from the GLD. The GLD is tested and succeeded to detect gases coming from an LPG cylinder and from a gas lighter. The GLD also runs perfectly for the designed early warning scheme.

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