On the Transition From Non-BLEVE to BLEVE Failure for a 1.8M3 Propane Tank

2006 ◽  
Vol 128 (4) ◽  
pp. 648-655 ◽  
Author(s):  
A. M. Birk ◽  
J. D. J. VanderSteen
Keyword(s):  
Pressure Vessels ◽  
Total Loss ◽  
Relief Valve ◽  
Initial Rupture ◽  
Asme Code ◽  
The Difference ◽  
Heated Length ◽  
Insight Into ◽  
Vapor Space ◽  
Fire Conditions

A series of fire tests were conducted on nine, 1.8m3(500USgal) ASME code propane pressure vessels to study the significance of pressure relief valve behavior on tank survivability to fire impingement. In these tests three tanks ruptured (i.e., finite failure) and six boiling liquid expanding vapor explosion (BLEVEd) (total loss of containment). The difference between the BLEVE and non-BLEVE failures was due to a difference in the fire conditions. It is believed that these tests show some insight into the BLEVE process. In all tests the fire consisted of an array of nominal 590kW(2MBTU∕h) liquid propane burners. A pool fire was not used because of the uncontrolled nature of open pool fires. It was believed that very repeatable fire conditions could be achieved by using a series of burners. In the tests where the outcome was a non-BLEVE there were two burners mounted 30cm above the tank on the tank vapor space. These burners were used to weaken the steel and to initiate a failure. To heat the liquid, there were between 4 and 12 burners applied below the liquid level. When one burner was added on the vapor space, all of the remaining tanks BLEVEd. This was true over a range of fill levels (at failure) of between 10% and 50% by volume. It is believed this added burner was just enough to weaken the tank so that any initial rupture would grow towards a total loss of containment and BLEVE. This paper presents the details of this test series and shows how severely heated length and liquid energy affected the outcome.

The Effect of Pressure Relief Valve Blowdown and Fire Conditions on the Thermo-Hydraulics Within a Pressure Vessel

2006 ◽  
Vol 128 (3) ◽  
pp. 467-475 ◽  
Author(s):  
A. M. Birk ◽  
J. D. J. VanderSteen
Keyword(s):  
Thermal Stratification ◽  
Pressure Vessels ◽  
Pressure Relief Valve ◽  
Relief Valve ◽  
Pressure Relief ◽  
Pressure Transducers ◽  
Hydrocarbon Pool ◽  
Computer Controlled ◽  
C 50 ◽  
Fire Conditions

In the summers of 2000 and 2001, a series of controlled fire tests were conducted on horizontal 1890liter (500 US gallon) propane pressure vessels. The test vessels were instrumented with pressure transducers, liquid space, vapor space, and wall thermocouples, and an instrumented flow nozzle in place of a pressure relief valve (PRV). A computer controlled PRV was used to control pressure. The vessels were heated using high momentum, liquid propane utility torches. Open pool fires were not used for the testing because they are strongly affected by wind. These wind effects make it almost impossible to have repeatable test conditions. The fire conditions used were calibrated to give heat inputs similar to a luminous hydrocarbon pool fire with an effective blackbody temperature in the range of 850°C±50°C. PRV blowdown (i.e., blowdown=poppressure−reclosepressure) and fire conditions were varied in this test series while all other input parameters were held constant. The fire conditions were varied by changing the number of burners applied to the vessel wall areas wetted by liquid and vapor. It was found that the vessel content’s response and energy storage varied according to the fire conditions and the PRV operation. The location and quantity of the burners affected the thermal stratification within the liquid, and the liquid swelling (due to vapor generation in the liquid) at the liquid∕vapor interface. The blowdown of the PRV affected the average vessel pressure, average liquid temperature, and time to temperature destratification in the liquid. Large blowdown also delayed thermal rupture.

Study on Flaw Acceptance Standard of ASME Code Sec. XI Based on Failure Probability

2004 ◽  
Author(s):  
Katsuyuki Shibata ◽  
Kunio Onizawa ◽  
YinSheng Li ◽  
Yasuhiro Kanto ◽  
Shinobu Yoshimura
Keyword(s):  
Case Studies ◽  
Failure Probability ◽  
Pressure Vessels ◽  
Aspect Ratios ◽  
Pressurized Thermal Shock ◽  
Asme Code ◽  
Order Of Magnitude ◽  
The Difference ◽  
Reactor Pressure

Based on the failure probability, the flaw acceptance standard of ASME Code Sec. XI is examined with some concerns weather the failure probability is uniform for flaws with various aspect ratios and failure frequencies are small enough. In this paper, the results of preliminary case studies are described on the failure probability of reactor pressure vessels (RPVs) with a surface flaw specified in Sec. XI. PFM code PASCAL was used for case studies. A PTS (Pressurized Thermal Shock) transient prescribed by NRC/EPRI PTS Benchmark Study was used as an applied load. Analysis results showed that the conditional failure probability of a RPV with an initial flaw of acceptable depth depends on the aspect ratio. In the case flaw shapes are close to semi-circular, the failure probability are higher than that of the cases aspect ration are less than 0.6 by one order of magnitude due to the difference of fracture behavior at the surface point. A case study for determining the acceptable flaws based on failure probability was also carried out.

The Effect of Reduced Design Margin on the Fire Survivability of ASME Code Propane Tanks

2004 ◽  
Author(s):  
A. M. Birk
Keyword(s):  
Pressure Vessels ◽  
Relief Valve ◽  
Pressure Relief ◽  
Mode Of Failure ◽  
Asme Code ◽  
Failure Scenario ◽  
Fill Level ◽  
Relief System ◽  
And Storage ◽  
Design Margin

The design margin on certain unfired pressure vessels has recently been reduced from 4.5 to 4.0 to 3.5. This has resulted in the manufacture of propane and LPG tanks with thinner walls. For example, some 500 gallon ASME code propane tanks have had the wall thickness reduced from 7.7 mm in 2001 to 7.1 mm in 2002 and now to 6.5 mm in 2004. This change significantly affects the fire survivability of these tanks. This paper presents both experimental and computational results that show the effect of this design change on tank fire survivability to fire impingement. The results show that for the same pressure relief valve setting, the thinner wall tanks are more likely to fail in a given fire situation. In severe fires, the thinner walled tanks will fail earlier. An earlier failure usually means the tank will fail with a higher fill level, because the pressure relief system has had less time to vent material from the tank. A higher liquid fill level at failure also means more energy is in the tank and this means the failure will be more violent. The worst failure scenario is known as a boiling liquid expanding vapour explosion (BLEVE) and this mode of failure is also more likely with the thinner walled tanks. The results of this work suggest that certain applications of pressure vessels such as propane transport and storage may require higher design margins than required by the ASME.

The Effect of Reduced Design Margin on the Fire Survivability of ASME Code Propane Tanks

2005 ◽  
Vol 127 (1) ◽  
pp. 55-60
Author(s):  
A. M. Birk
Keyword(s):  
Wall Thickness ◽  
Pressure Vessels ◽  
Relief Valve ◽  
Pressure Relief ◽  
Asme Code ◽  
Section Viii ◽  
Failure Scenario ◽  
Fill Level ◽  
Relief System ◽  
Design Margin

In the 1999 addenda to the 1998 ASME pressure vessel code, Section VIII, Div. 1 there was a change in design margin for unfired pressure vessels from 4.0 to 3.5. This has resulted in the manufacture of propane and LPG tanks with thinner walls. For example, the author has purchased some new 500 gallon ASME code propane tanks for testing purposes. These tanks had the wall thickness reduced from 7.7 mm in 2000 to 7.1 mm in 2002 and now to 6.5 mm in 2004. These changes were partly due to the code change and partly due to other factors such as steel plate availability. In any case, the changes in wall thickness significantly affects the fire survivability of these tanks. This paper presents both experimental and computational results that show the effect of wall thickness on tank survivability to fire impingement. The results show that for the same dank diameter, tank material, and pressure relief valve setting, the thinner wall tanks are more likely to fail in a given fire situation. In severe fires, the thinner walled tanks will fail earlier. An earlier failure usually means the tank will fail with a higher fill level, because the pressure relief system has had less time to vent material from the tank. A higher liquid fill level at failure also means more energy is in the tank and this means the failure will be more violent. The worst failure scenario is known as a boiling liquid expanding vapor explosion and this mode of failure is also more likely with the thinner walled tanks. The results of this work suggest that certain applications of pressure vessels such as propane transport and storage may require higher design margins than required by Section VIII ASME code.

HYPOCHROMIC MICROCYTIC ANEMIA OF INFANCY: IRON DEPLETION AS A FACTOR

PEDIATRICS ◽  
1956 ◽  
Vol 18 (6) ◽  
pp. 959-978
Author(s):  
Hugh W. Josephs
Keyword(s):  
Iron Deficiency ◽  
Severe Infection ◽  
Microcytic Anemia ◽  
Severe Anemia ◽  
Iron Depletion ◽  
Hypochromic Microcytic Anemia ◽  
Premature Babies ◽  
Number Of Factors ◽  
The Difference ◽  
Insight Into

In this work the author has attempted to gain insight into the significance of iron depletion by the use of 4 simple calculations, justification for which is found in recent articles. These are: (a) iron with which the infant is born; (b) iron retained from the food; (c) iron being used by the tissues and therefore unavailable for hemoglobin, and (d) iron combined with the total mass of hemoglobin. With these 4 figures it is possible to estimate the iron still potentially available for use (the "reserves" or "stones"). When the difference between a + b and c + d has reached about zero, depletion is considered to exist. The following characteristics of depletion may be emphasized: Depletion is the result of gain in weight and maximum possible usage of iron. It is therefore a normal result of growth and need not be associated with anemia. As soon as depletion has occurred, the organism is thereafter dependent on current absorption of iron. This is ordinarily sufficient, even with a diet of milk alone, to maintain an adequate concentration of hemoglobin after about 8 to 10 months of age. Severe anemia due to depletion alone is practically confined to premature babies whose relative gain in weight is rapid. Severe anemia in other than premature babies is the result of a number of factors by which iron becomes unavailable or is actually diverted from hemoglobin to storage. Response to iron medication is considerably better in infants with depletion than in those in whom some factor is present that interferes with iron utilization, and which is not connected by the mere giving of iron. The dependence on current absorption, whether the result of depletion or non-availability, introduces a certain precariousness which is apparently characteristic of this time of life. The organism gets along from day to day if nothing happens, but may not be able to meet an emergency, whether this appears as a rapid gain in weight, or a necessity to repair damage done by severe infection. If we consider iron deficiency as the cause of anemia, we can think of deficiency as due to a number of factors of which depletion is only one. The development and characteristics of depletion have been considered in this paper; other factors in iron deficiency will be considered in subsequent papers.

Dynamic Behavior of Transportation Pressure Relief Valves Under Simulated Fire Impingement Conditions

1999 ◽  
Vol 122 (1) ◽  
pp. 60-65 ◽  
Author(s):  
A. J. Pierorazio ◽  
A. M. Birk
Keyword(s):  
Dynamic Testing ◽  
Test Facility ◽  
Time Varying ◽  
Relief Valve ◽  
Pressure Relief ◽  
Flow Rates ◽  
Depth Analysis ◽  
Pressure Relief Valves ◽  
Accident Conditions ◽  
Insight Into

This paper presents the results of the first full test series of commercial pressure relief valves using the newly constructed Queen’s University/Transport Canada dynamic valve test facility (VTF) in Maitland, Ontario. This facility is unique among those reported in the literature in its ability to cycle the valves repeatedly and to measure the time-varying flow rates during operation. This dynamic testing provides much more insight into valve behavior than the single-pop or continuous flow tests commonly reported. The facility is additionally unique in its simulation of accident conditions as a means of measuring valve performance. Specimen valves for this series represent 20 each of three manufacturers’ design for a semi-internal 1-in. 312 psi LPG relief valve. The purpose of this paper is to present the procedure and results of these tests. No effort is made to perform in-depth analysis into the causes of the various behaviors, nor is any assessment made of the risk presented by any of the valves. [S0094-9930(00)01201-4]

Design Formulas of Blind End Closures for High Pressure Vessels

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
R. D. Dixon ◽  
E. H. Perez
Keyword(s):  
High Pressure ◽  
Fatigue Life ◽  
Maximum Stress ◽  
Accurate Determination ◽  
Pressure Vessels ◽  
Stress Distributions ◽  
Fatigue And Fracture ◽  
Asme Code ◽  
Section Viii

The available design formulas for flat heads and blind end closures in the ASME Code, Section VIII, Divisions 1 and 2 are based on bending theory and do not apply to the design of thick flat heads used in the design of high pressure vessels. This paper presents new design formulas for thickness requirements and determination of peak stresses and stress distributions for fatigue and fracture mechanics analyses in thick blind ends. The use of these proposed design formulas provide a more accurate determination of the required thickness and fatigue life of blind ends. The proposed design formulas are given in terms of the yield strength of the material and address the fatigue strength at the location of the maximum stress concentration factor. Introduction of these new formulas in a nonmandatory appendix of Section VIII, Division 3 is recommended after committee approval.

scholarly journals Experimental Study on the Transition between Static and Kinetic Frictions of Steel/Shale Pairs

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Qin Lian ◽  
Chunxu Yang ◽  
Jifei Cao
Keyword(s):  
Friction Coefficient ◽  
Normal Load ◽  
Critical Distance ◽  
Dynamic Friction ◽  
Stick Slip ◽  
Dynamic Friction Coefficient ◽  
The Coefficient Of Friction ◽  
The Difference ◽  
Stick Slip Motion ◽  
Insight Into

The transition between static and kinetic frictions of steel/shale pairs has been studied. It was found that the coefficient of friction decreased exponentially from static to dynamic friction coefficient with increasing sliding displacement. The difference between static and dynamic friction coefficients and the critical distance Dc under the dry friction condition is much larger than that under the lubricated condition. The transition from static to dynamic friction coefficient is greatly affected by the normal load, quiescent time, and sliding velocity, especially the lubricating condition. Maintaining continuous lubrication of the contact area by the lubricant is crucial to reduce or eliminate the stick-slip motion. The results provide an insight into the transition from static to dynamic friction of steel/shale pairs.

scholarly journals An Insight Into the Value Added Tax System Detailing Its Origins, Impact, Provisions and Regulations With Reference to India

2004 ◽  
Vol 3 (1) ◽  
pp. 19-29
Author(s):  
Tomy Kallarackal
Keyword(s):  
European Economic Community ◽  
Value Added ◽  
Tax Credit ◽  
Value Added Tax ◽  
Excise Duty ◽  
Goods And Services ◽  
The World ◽  
The Difference ◽  
The Government ◽  
Insight Into

The Value Added Tax was first introduced in France in 1954. It was the resultant effort of France and members of the European Economic Community (E.E.C) during the 1950s aimed at the simplification of commodity taxes. Currently more than 130 nations in the world have adopted the VAT system. In the last decade alone over 50 nations have introduced VAT. This includes implementation in China and most recently the addition of Australia to the list of VAT nations. The world over, VAT is payable on both goods and services as they constitute a part of the national GDR Excise duty and sales taxes are merged into the singularity of VAT. No tax is levied on exports with full input tax credit made available. The scheme of taxation adopted by most nations is very simple. The seller of goods and the service provider charge tax on sales, avail input tax credit and pay the difference as VAT to the goVernment treasury. The compliance system in VAT nations is also very simple. There is very less interface between the tax collector and the tax payer. However there are provisions for heavy penalization of VAT defaulters. VAT is administered nationally and is also levied on imports.  

scholarly journals Converging physiological roles of the anthrax toxin receptors

F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 1415
Author(s):  
Oksana A. Sergeeva ◽  
F. Gisou van der Goot
Keyword(s):  
Anthrax Toxin ◽  
Loss Of Function ◽  
Disease Symptoms ◽  
Hyaline Fibromatosis Syndrome ◽  
Anthrax Toxins ◽  
The Difference ◽  
Related Proteins ◽  
Tumor Endothelial Marker 8 ◽  
Insight Into ◽  
Shed Light

The anthrax toxin receptors—capillary morphogenesis gene 2 (CMG2) and tumor endothelial marker 8 (TEM8)—were identified almost 20 years ago, although few studies have moved beyond their roles as receptors for the anthrax toxins to address their physiological functions. In the last few years, insight into their endogenous roles has come from two rare diseases: hyaline fibromatosis syndrome, caused by mutations in CMG2, and growth retardation, alopecia, pseudo-anodontia, and optic atrophy (GAPO) syndrome, caused by loss-of-function mutations in TEM8. Although CMG2 and TEM8 are highly homologous at the protein level, the difference in disease symptoms points to variations in the physiological roles of the two anthrax receptors. Here, we focus on the similarities between these receptors in their ability to regulate extracellular matrix homeostasis, angiogenesis, cell migration, and skin elasticity. In this way, we shed light on how mutations in these two related proteins cause such seemingly different diseases and we highlight the existing knowledge gaps that could form the focus of future studies.

Sign in / Sign up

Export Citation Format

Share Document