scholarly journals Investigation of Adhesion Formation in New Stainless Steel Trim Spring Operated Pressure Relief Valves

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Julia V. Bukowski ◽  
Robert E. Gross ◽  
William M. Goble
Keyword(s):  
Stainless Steel ◽  
Test Data ◽  
Adhesion Formation ◽  
End Users ◽  
Excess Pressure ◽  
Pressure Relief ◽  
Significant Percentage ◽  
Pressure Relief Valves

Examination of proof test data for new (not previously installed) stainless steel (SS) trim spring operated pressure relief valves (SOPRV) reveals that adhesions form between the seat and disk in about 46% of all such SOPRV. The forces needed to overcome these adhesions can be sufficiently large to cause the SOPRV to fail its proof test (FPT) prior to installation. Furthermore, a significant percentage of SOPRV which are found to FPT are also found to “fail to open” (FTO) meaning they would not relief excess pressure in the event of an overpressure event. The cases where adhesions result in FTO or FPT appear to be confined to SOPRV with diameters less than or equal to 1 in. and set pressures less than 150 pounds per square inch gauge (psig) and the FTO are estimated to occur in 0.31% to 2.00% of this subpopulation of SS trim SOPRV. The reliability and safety implications of these finding for end users who do not perform pre-installation testing of SOPRV are discussed.

scholarly journals Investigation of Adhesion Formation in New Stainless Steel Trim Spring Operated Pressure Relief Valves

2013 ◽  
Author(s):  
Julia V. Bukowski ◽  
Robert E. Gross ◽  
William M. Goble
Keyword(s):  
Stainless Steel ◽  
Test Data ◽  
Adhesion Formation ◽  
End Users ◽  
Excess Pressure ◽  
Pressure Relief ◽  
Significant Percentage ◽  
Pressure Relief Valves

Examination of proof test data for new (not previously installed) stainless steel (SS) trim spring operated pressure relief valves (SOPRV) reveals that adhesions form between the seat and disc in about 46% of all such SOPRV. The forces needed to overcome these adhesions can be sufficiently large to cause the SOPRV to fail its proof test (FPT) prior to installation. Furthermore, a significant percentage of SOPRV which are found to FPT are also found to “fail to open” (FTO) meaning they would not relief excess pressure in the event of an overpressure event. The cases where adhesions result in FTO or FPT appear to be confined to SOPRV with diameters ≤ 1 in and set pressures < 150 psig and the FTO are estimated to occur in 0.31% to 2.00% of this subpopulation of SS trim SOPRV. The reliability and safety implications of these finding for end-users who do not perform pre-installation testing of SOPRV are discussed.

The Adhesion Failure Mode in Stainless Steel Trim Spring Operated Pressure Relief Valves

2012 ◽  
Author(s):  
Julia V. Bukowski ◽  
Robert E. Gross ◽  
William M. Goble
Keyword(s):  
Stainless Steel ◽  
Failure Mode ◽  
Failure Rate ◽  
Failure Modes ◽  
Service Failure ◽  
Failure Rates ◽  
Pressure Relief ◽  
Safety Integrity Level ◽  
Adhesion Failure ◽  
Pressure Relief Valves

This paper addresses dangerous failures of stainless steel (SS) trim spring operated pressure relief valves (SOPRV) due to a particular failure mode (SS-to-SS adhesion) which is not currently being included in SOPRV failure rates. As a result, current methods for estimating or predicting failure rates for SS trim SOPRV significantly underestimate these failure rates and, consequently, overestimate the safety provided by the SOPRV as measured by its average probability of failure on demand (PFDavg) or its corresponding safety integrity level (SIL). The paper also illustrates the critical importance of root cause analysis (RCA) of dangerous SOPRV failures in understanding the impacts of various failure modes. Over 1300 proof test results for both new and used SS trim SOPRV from the Savannah River Site (SRS) were identified. RCA was used on the failed valves to classify those failed due to SS-to-SS adhesions. Statistical analysis of the data convincingly demonstrates adhesions, previously assumed to be only an in-storage failure phenomenon, are also an in-service failure mode which needs to be included in SOPRV failure rates. The paper discusses the factors which potentially influence the adhesion failure mode and suggests a possible approach to including this mode in failure rate predictions. An example illustrates how current failure rate models overestimate SS trim SOPRV safety by one or two orders of magnitude.

The Adhesion Failure Mode in Stainless Steel Trim Spring-Operated Pressure Relief Valves

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Julia V. Bukowski ◽  
Robert E. Gross ◽  
William M. Goble
Keyword(s):  
Stainless Steel ◽  
Failure Mode ◽  
Failure Rate ◽  
Failure Modes ◽  
Service Failure ◽  
Failure Rates ◽  
Pressure Relief ◽  
Safety Integrity Level ◽  
Adhesion Failure ◽  
Pressure Relief Valves

This paper addresses dangerous failures of stainless steel (SS) trim spring-operated pressure relief valves (SOPRV) due to a particular failure mode (SS-to-SS adhesion), which is not currently being included in SOPRV failure rates. As a result, current methods for estimating or predicting failure rates for SS trim SOPRV significantly underestimate these failure rates and, consequently, overestimate the safety provided by the SOPRV as measured by its average probability of failure on demand (PFDavg) or its corresponding safety integrity level (SIL). The paper also illustrates the critical importance of root cause analysis (RCA) of dangerous SOPRV failures in understanding the impacts of various failure modes. Over 1300 proof test results for both new and used SS trim SOPRV from the Savannah River Site (SRS) were identified. RCA was used on the failed valves to classify those failed due to SS-to-SS adhesions. Statistical analysis of the data convincingly demonstrates adhesions, previously assumed to be only an in-storage failure phenomenon, are also an in-service failure mode, which needs to be included in SOPRV failure rates. The paper discusses the factors which potentially influence the adhesion failure mode, and suggests a possible approach to including this mode in failure rate predictions. An example illustrates how current failure rate models overestimate SS trim SOPRV safety by 1 or 2 orders of magnitude.

scholarly journals Effects of Seat Width on Development of Adhesions in Stainless Steel Trim Spring Operated Pressure Relief Valves

2015 ◽  
Author(s):  
Julia V. Bukowski ◽  
Robert E. Gross ◽  
William M. Goble ◽  
Stephen P. Harris
Keyword(s):  
Stainless Steel ◽  
Safety Performance ◽  
Pressure Relief ◽  
Additional Force ◽  
Process Pressure ◽  
Spring Force ◽  
Pressure Relief Valves ◽  
Study Population ◽  
Process Fluid

Previous research has shown that stainless steel (SS) adhesions form in about half of new SS trim spring operated pressure relief valves (SOPRV). These adhesions require an additional force (beyond the spring force) to be applied by the process fluid to the disc in order for the valve to lift. This additional force may cause the SOPRV to fail its proof test (FPT) or even to fail to open (FTO) in the presence of excess process pressure. This paper expands on the previous findings to show how seat width relates statistically to whether or not these SS adhesions form and, if they do, whether or not they are of sufficient size to cause FPT or FTO. The findings show it is statistically significant that SOPRV in the study population with seat widths greater than 0.030 inches (in.) formed adhesions more often than SOPRV with seat widths less than or equal to 0.030 in. Furthermore, for this population it is statistically significant that all FPT and FTO occurred on SOPRV with seat widths greater than or equal to 0.030 in. The ramifications of these findings to the safety performance of SS trim SOPRV are discussed.

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]

scholarly journals Forensic Engineering Techniques For Testing And Predicting Lp-Gas Container Relief Venting

2004 ◽  
Vol 21 (2) ◽  
Author(s):  
James A. Petersen
Keyword(s):  
Test Data ◽  
Pressure Relief Valve ◽  
Relief Valve ◽  
Pressure Relief ◽  
Temperature Changes ◽  
Flammable Gas ◽  
Forensic Engineering ◽  
Pressure Changes ◽  
Liquefied Gas

When An Lp-Gas Container Is Involved In A Fire, Flammable Gas Is Usually Vented From The Relief Valve. One Of The First Questions Is Whether The Container Vented The Gas That Caused The Fire Or Whether Gas Was Vented Due To The Fire Heating The Container. If The Relief Valve Vents Gas That Initiates The Fire, It Is Usually Due To An Overfilled Container. This Paper Discusses; 1) The Prediction Of The Rate Of Container Warming Due To Normal Temperature Changes, 2) The Resulting Pressure Changes Of The Liquefied Gas, 3) The Reaction Of The Pressure Relief Valve And The Quantity Of Lp-Gas Vented During The Operation Of The Relief Valve, 4) Designing The Experiment And 4) Adjusting The Model To Reflect Test Data.

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