scholarly journals Analysis of emergency situations on low pressure gas pipelines in case of failure of gas control points

2021 ◽  
pp. 90-93
Author(s):  
Elena Borisovna Solovyeva
Keyword(s):  
Small Diameter ◽  
Low Pressure ◽  
Control Points ◽  
Gas Pipelines ◽  
Emergency Situations ◽  
Main Equipment ◽  
Gas Control ◽  
Emergency Mode ◽  
Mode A ◽  
Back Part

The analysis of malfunctions of the main equipment at gas control points was carried out. It was concluded that for the looped-back part of the low-pressure network, the diameters of adjacent sections should not be significantly different, since if the diameter of one section is less than the neighboring one, then in an emergency mode, a section with a small diameter will not let in the required amount of gas.

Comparison of PIR to PIPESAFE-Based 1% Lethality Zones for Natural Gas Pipelines

2014 ◽  
Author(s):  
Aleksandar Tomic ◽  
Shahani Kariyawasam
Keyword(s):  
Natural Gas ◽  
Small Diameter ◽  
Gas Pipeline ◽  
Accurate Estimation ◽  
Simple Relationship ◽  
Gas Pipelines ◽  
Friction Forces ◽  
Natural Gas Pipelines ◽  
Decay Factor ◽  
Outflow Rate

A lethality zone due to an ignited natural gas release is often used to characterize the consequences of a pipeline rupture. A 1% lethality zone defines a zone where the lethality to a human is greater than or equal to 1%. The boundary of the zone is defined by the distance (from the point of rupture) at which the probability of lethality is 1%. Currently in the gas pipeline industry, the most detailed and validated method for calculating this zone is embodied in the PIPESAFE software. PIPESAFE is a software tool developed by a joint industry group for undertaking quantitative risk assessments of natural gas pipelines. PIPESAFE consequence models have been verified in laboratory experiments, full scale tests, and actual failures, and have been extensively used over the past 10–15 years for quantitative risk calculations. The primary advantage of using PIPESAFE is it allows for accurate estimation of the likelihood of lethality inside the impacted zone (i.e. receptors such as structures closer to the failure are subject to appropriately higher lethality percentages). Potential Impact Radius (PIR) is defined as the zone in which the extent of property damage and serious or fatal injury would be expected to be significant. It corresponds to the 1% lethality zone for a natural gas pipeline of a certain diameter and pressure when thermal radiation and exposure are taken into account. PIR is one of the two methods used to identify HCAs in US (49 CFR 192.903). Since PIR is a widely used parameter and given that it can be interpreted to delineate a 1% lethality zone, it is important to understand how PIR compares to the more accurate estimation of the lethality zones for different diameters and operating pressures. In previous internal studies, it was found that PIR, when compared to the more detailed measures of the 1% lethality zone, could be highly conservative. This conservatism could be beneficial from a safety perspective, however it is adding additional costs and reducing the efficiency of the integrity management process. Therefore, the goal of this study is to determine when PIR is overly conservative and to determine a way to address this conservatism. In order to assess its accuracy, PIR was compared to a more accurate measure of the 1% lethality zone, calculated by PIPESAFE, for a range of different operating pressures and line diameters. Upon comparison of the distances calculated through the application of PIR and PIPESAFE, it was observed that for large diameters pipelines the distances calculated by PIR are slightly conservative, and that this conservativeness increases exponentially for smaller diameter lines. The explanation for the conservatism of the PIR for small diameter pipelines is the higher wall friction forces per volume transported in smaller diameter lines. When these higher friction forces are not accounted for it leads to overestimation of the effective outflow rate (a product of the initial flow rate and the decay factor) which subsequently leads to the overestimation of the impact radius. Since the effective outflow rate is a function of both line pressure and diameter, a simple relationship is proposed to make the decay factor a function of these two variables to correct the excess conservatism for small diameter pipelines.

scholarly journals Water Ingress Detection in Low-Pressure Gas Pipelines Using Distributed Temperature Sensing System

2017 ◽  
Vol 17 (10) ◽  
pp. 3165-3173 ◽  
Author(s):  
Libo Wang ◽  
Srivathsan Chakaravarthi Narasimman ◽  
Sugunakar Reddy Ravula ◽  
Abhisek Ukil
Keyword(s):  
Low Pressure ◽  
Temperature Sensing ◽  
Gas Pipelines ◽  
Distributed Temperature Sensing ◽  
Water Ingress ◽  
Sensing System

System for detection of the location of leaks in gas pipelines of low pressure

1998 ◽  
Vol 41 (5) ◽  
pp. 477-479 ◽  
Author(s):  
O. A. Tumshis ◽  
L. V. Yakyavichyus
Keyword(s):  
Low Pressure ◽  
Gas Pipelines

scholarly journals Corrosion of Underground Low Pressure Gas Pipelines under Alternate Current

2016 ◽  
Vol 26 (3) ◽  
pp. 306-311
Author(s):  
L.Ya. Poberezhny ◽  
A.V. Yavorskyy
Keyword(s):  
Alternate Current ◽  
Low Pressure ◽  
Gas Pipelines

scholarly journals Influence of the shape and size of the ground targets on the accuracy of photogrammetric processing

2020 ◽  
Vol 28 (3) ◽  
pp. 293-304
Author(s):  
Amr Elsheshtawy ◽  
Larisa A. Gavrilova ◽  
Anatoly N. Limonov ◽  
Mohamed Elshewy
Keyword(s):  
Large Scale ◽  
Soil Layer ◽  
Aerial Survey ◽  
Control Points ◽  
Aerial Photos ◽  
Emergency Situations ◽  
Ground Control Points ◽  
First Case ◽  
Aerial Vehicle ◽  
Mosaic Generation

The materials obtained from the unmanned aerial vehicle (UAV) are used to solve many problems, including large-scale mapping and monitoring of linear objects, as well as the ecological situation and monitoring of emergency situations. The promptly obtained photographic materials make it possible to reveal the consequences of man-made human impact associated with degradation of the soil cover, flooding of lands, salinization and pollution of the soil layer, and changes in the vegetation cover. Control points are used for absolute orientation of the generated models in the most projects of photogrammetric processing of aerial photos and images obtained from UAVs. In areas with low contour, before aerial survey, targeting is carried out in the required zones. The research is devoted to the study of the influence of the shape of ground targets on the accuracy of photogrammetric processing. It involved three different types of ground targets located on the land cover along the survey path at a distance not exceeding 1 m from each other. The targets were used as ground control points in the photogrammetric processing of the materials from the UAV. Two three-stripe photographic surveys of the 900 m long track were carried out: with UAV DJI PHANTOM 4 PRO camera FC6310 at a scale of 1:3400 and ground resolution of 1 cm and with the DJI Mavic PRO UAV camera FC220 at a scale of 1:12 700 and ground resolution of 2 cm. In both cases, the direction of flight is north - south, 36 targets were included in the photogrammetric processing. In the first case, 502 images were processed, in the second - 152. The photogrammetric processing for the orthophoto mosaic generation was carried out using the Agisoft Photo Scan Professional software. Four different contrasting sites in the study area were selected for the study: green grass, dry grass, clay, sand. Accuracy was assessed according to two criteria: 1) the degree of visualization of the target on the images; 2) the accuracy of the orthophoto mosaic, generated using various targets.

A Novel Approach to Risk Management of Belowground Natural Gas Migration From Leaks on Low-Pressure Pipelines

2020 ◽  
Author(s):  
Kim Maddin ◽  
Dongliang Lu ◽  
Aleksandar Tomic
Keyword(s):  
Risk Assessment ◽  
Public Safety ◽  
Management Practices ◽  
Small Diameter ◽  
Low Pressure ◽  
The United States ◽  
Operating Conditions ◽  
Gas Migration ◽  
Confined Space ◽  
Leak Management

Abstract Small-diameter, low-pressure pipelines (operated at pressures below 40 percent of specified minimum yield strength [SMYS]) are unlikely to experience a rupture but may be vulnerable to leaks. In general, gas leaks result in less significant consequences to public safety than ruptures; however, under certain circumstances leaks may represent a significant threat. In particular, leaks resulting in belowground gas migration from low-pressure pipelines to a nearby confined space (e.g. the basement of a nearby structure to which the pipeline is not physically connected) may result in significant consequences as accumulation of gas to flammable or explosive levels may be possible. This paper explores the methods by which an Operator may address the threat of gas migration from leaks on low pressure pipelines in its risk assessment and leak management programs. Research was conducted into the specific conditions that contribute to belowground gas migration and included: a literature review of studies into gas migration phenomena, and a review of historical incidents within the United States on similar pipeline systems which resulted in significant property damage, injuries, or fatalities. The research included consideration of the effect of pipeline operating conditions, pipeline attributes (including diameter and depth of cover), leak duration, proximity of nearby structures, attributes of nearby structures (including presence of basements, slabs, and openings in the foundations), leak severity (e.g. pinhole, full separation), ground conditions (including soil permeability and presence of belowground features), and gas odorization. Key conditions impacting the potential for belowground gas migration are identified, and risk assessment methods and leak management practices are recommended based on the likelihood of migration. Based on the research conducted and the environmental conditions identified, a quantitative risk assessment approach, taking into account the likelihood of a leak on a low-pressure pipeline, the likelihood of belowground gas migration, and the potential consequences to public safety, is proposed.

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