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Robert E. Gross - One of the best experts on this subject based on the ideXlab platform.

  • STATISTICAL PERFORMANCE EVALUATION OF SPRING OPERATED Pressure Relief VALVE RELIABILITY IMPROVEMENTS 2004 TO 2014
    Volume 6B: Materials and Fabrication, 2015
    Co-Authors: Holly L. Watson, Robert E. Gross, Stephen P. Harris
    Abstract:

    The United States Department of Energy’s Savannah River Site (SRS) in Aiken, South Carolina, is dedicated to promoting site-level risk-based inspection (RBI) practices in order to maintain a safe and productive work environment. Inspecting component parts of operational systems, such as Pressure Relief Valves (PRVs), is a vital part of SRS’s safe operating envelope. This paper is a continuation of a SRS program to minimize the risks associated with PRV failures. Spring operated Pressure Relief valve (SOPRV) test data accumulated over the past ten years resulted in over 11,000 proof tests of both new and used Valves. Improved performance is seen for air service Valves resulting from changes to the maintenance program. Although, statistically significant improvement was not seen for liquid, gas, or steam service Valves, analysis shows that the overall probability of failure on demand is trending down. Current SRS practices are reviewed and the reasons for improved performance are explored.Copyright © 2015 by ASME

  • effects of seat width on development of adhesions in stainless steel trim spring operated Pressure Relief Valves
    ASME 2015 Pressure Vessels and Piping Conference, 2015
    Co-Authors: Julia V. Bukowski, Robert E. Gross, William M. Goble, Stephen P. Harris
    Abstract:

    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.Copyright © 2015 by ASME

  • investigation of adhesion formation in new stainless steel trim spring operated Pressure Relief Valves
    Journal of Pressure Vessel Technology-transactions of The Asme, 2014
    Co-Authors: Julia V. Bukowski, Robert E. Gross, William M. Goble
    Abstract:

    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.

  • The Effects of Maintenance Actions on the PFDavg of Spring Operated Pressure Relief Valves
    Volume 6B: Materials and Fabrication, 2014
    Co-Authors: Julia V. Bukowski, Robert E. Gross, William M. Goble, Stephen P. Harris
    Abstract:

    The safety integrity level (SIL) of equipment used in safety instrumented functions is determined by the average probability of failure on demand (PFDavg) computed at the time of periodic inspection and maintenance, i.e., the time of proof testing. The computation of PFDavg is generally based solely on predictions or estimates of the assumed constant failure rate of the equipment. However, PFDavg is also affected by maintenance actions (or lack thereof) taken by the end user. This paper shows how maintenance actions can affect the PFDavg of spring operated Pressure Relief Valves (SOPRV) and how these maintenance actions may be accounted for in the computation of the PFDavg metric. The method provides a means for quantifying the effects of changes in maintenance practices and shows how these changes impact plant safety.

  • Statististical Performance Evaluation of Soft Seat Pressure Relief Valves
    Journal of Pressure Vessel Technology, 2014
    Co-Authors: Robert E. Gross, Stephen P. Harris
    Abstract:

    Risk-based inspection methods enable estimation of the probability of failure on demand for spring-operated Pressure Relief Valves at the United States Department of Energy's Savannah River Site in Aiken, South Carolina. This paper presents a statistical performance evaluation of soft seat spring operated Pressure Relief Valves. These Pressure Relief Valves are typically smaller and of lower cost than hard seat (metal to metal) Pressure Relief Valves and can provide substantial cost savings in fluid service applications (air, gas, liquid, and steam) providing that probability of failure on demand (the probability that the Pressure Relief valve fails to perform its intended safety function during a potentially dangerous over pressurization) is at least as good as that for hard seat Valves. The research in this paper shows that the proportion of soft seat spring operated Pressure Relief Valves failing is the same or less than that of hard seat Valves, and that for failed Valves, soft seat Valves typically have failure ratios of proof test Pressure to set Pressure less than that of hard seat Valves.

William M. Goble - One of the best experts on this subject based on the ideXlab platform.

  • effects of seat width on development of adhesions in stainless steel trim spring operated Pressure Relief Valves
    ASME 2015 Pressure Vessels and Piping Conference, 2015
    Co-Authors: Julia V. Bukowski, Robert E. Gross, William M. Goble, Stephen P. Harris
    Abstract:

    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.Copyright © 2015 by ASME

  • investigation of adhesion formation in new stainless steel trim spring operated Pressure Relief Valves
    Journal of Pressure Vessel Technology-transactions of The Asme, 2014
    Co-Authors: Julia V. Bukowski, Robert E. Gross, William M. Goble
    Abstract:

    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.

  • The Effects of Maintenance Actions on the PFDavg of Spring Operated Pressure Relief Valves
    Volume 6B: Materials and Fabrication, 2014
    Co-Authors: Julia V. Bukowski, Robert E. Gross, William M. Goble, Stephen P. Harris
    Abstract:

    The safety integrity level (SIL) of equipment used in safety instrumented functions is determined by the average probability of failure on demand (PFDavg) computed at the time of periodic inspection and maintenance, i.e., the time of proof testing. The computation of PFDavg is generally based solely on predictions or estimates of the assumed constant failure rate of the equipment. However, PFDavg is also affected by maintenance actions (or lack thereof) taken by the end user. This paper shows how maintenance actions can affect the PFDavg of spring operated Pressure Relief Valves (SOPRV) and how these maintenance actions may be accounted for in the computation of the PFDavg metric. The method provides a means for quantifying the effects of changes in maintenance practices and shows how these changes impact plant safety.

  • investigation of adhesion formation in new stainless steel trim spring operated Pressure Relief Valves
    ASME 2013 Pressure Vessels and Piping Conference, 2013
    Co-Authors: Julia V. Bukowski, Robert E. Gross, William M. Goble
    Abstract:

    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
    ASME 2012 Pressure Vessels and Piping Conference, 2012
    Co-Authors: Julia V. Bukowski, Robert E. Gross, William M. Goble
    Abstract:

    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.Copyright © 2012 by ASME

Stephen P. Harris - One of the best experts on this subject based on the ideXlab platform.

  • STATISTICAL PERFORMANCE EVALUATION OF SPRING OPERATED Pressure Relief VALVE RELIABILITY IMPROVEMENTS 2004 TO 2014
    Volume 6B: Materials and Fabrication, 2015
    Co-Authors: Holly L. Watson, Robert E. Gross, Stephen P. Harris
    Abstract:

    The United States Department of Energy’s Savannah River Site (SRS) in Aiken, South Carolina, is dedicated to promoting site-level risk-based inspection (RBI) practices in order to maintain a safe and productive work environment. Inspecting component parts of operational systems, such as Pressure Relief Valves (PRVs), is a vital part of SRS’s safe operating envelope. This paper is a continuation of a SRS program to minimize the risks associated with PRV failures. Spring operated Pressure Relief valve (SOPRV) test data accumulated over the past ten years resulted in over 11,000 proof tests of both new and used Valves. Improved performance is seen for air service Valves resulting from changes to the maintenance program. Although, statistically significant improvement was not seen for liquid, gas, or steam service Valves, analysis shows that the overall probability of failure on demand is trending down. Current SRS practices are reviewed and the reasons for improved performance are explored.Copyright © 2015 by ASME

  • effects of seat width on development of adhesions in stainless steel trim spring operated Pressure Relief Valves
    ASME 2015 Pressure Vessels and Piping Conference, 2015
    Co-Authors: Julia V. Bukowski, Robert E. Gross, William M. Goble, Stephen P. Harris
    Abstract:

    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.Copyright © 2015 by ASME

  • The Effects of Maintenance Actions on the PFDavg of Spring Operated Pressure Relief Valves
    Volume 6B: Materials and Fabrication, 2014
    Co-Authors: Julia V. Bukowski, Robert E. Gross, William M. Goble, Stephen P. Harris
    Abstract:

    The safety integrity level (SIL) of equipment used in safety instrumented functions is determined by the average probability of failure on demand (PFDavg) computed at the time of periodic inspection and maintenance, i.e., the time of proof testing. The computation of PFDavg is generally based solely on predictions or estimates of the assumed constant failure rate of the equipment. However, PFDavg is also affected by maintenance actions (or lack thereof) taken by the end user. This paper shows how maintenance actions can affect the PFDavg of spring operated Pressure Relief Valves (SOPRV) and how these maintenance actions may be accounted for in the computation of the PFDavg metric. The method provides a means for quantifying the effects of changes in maintenance practices and shows how these changes impact plant safety.

  • Statististical Performance Evaluation of Soft Seat Pressure Relief Valves
    Journal of Pressure Vessel Technology, 2014
    Co-Authors: Robert E. Gross, Stephen P. Harris
    Abstract:

    Risk-based inspection methods enable estimation of the probability of failure on demand for spring-operated Pressure Relief Valves at the United States Department of Energy's Savannah River Site in Aiken, South Carolina. This paper presents a statistical performance evaluation of soft seat spring operated Pressure Relief Valves. These Pressure Relief Valves are typically smaller and of lower cost than hard seat (metal to metal) Pressure Relief Valves and can provide substantial cost savings in fluid service applications (air, gas, liquid, and steam) providing that probability of failure on demand (the probability that the Pressure Relief valve fails to perform its intended safety function during a potentially dangerous over pressurization) is at least as good as that for hard seat Valves. The research in this paper shows that the proportion of soft seat spring operated Pressure Relief Valves failing is the same or less than that of hard seat Valves, and that for failed Valves, soft seat Valves typically have failure ratios of proof test Pressure to set Pressure less than that of hard seat Valves.

  • Statistical Performance Evaluation of Soft (Elastomer) Seat Pressure Relief Valves
    Volume 6A: Materials and Fabrication, 2013
    Co-Authors: Robert E. Gross, Stephen P. Harris
    Abstract:

    Risk-based inspection methods enable estimation of the probability of failure on demand for spring-operated Pressure Relief Valves at the United States Department of Energy’s Savannah River Site in Aiken, South Carolina. This paper presents a statistical performance evaluation of soft seat spring operated Pressure Relief Valves. These Pressure Relief Valves are typically smaller and of lower cost than hard seat (metal to metal) Pressure Relief Valves and can provide substantial cost savings in fluid service applications (air, gas, liquid, and steam) providing that probability of failure on demand (the probability that the Pressure Relief valve fails to perform its intended safety function during a potentially dangerous over pressurization) is at least as good as that for hard seat Valves. The research in this paper shows that the proportion of soft seat spring operated Pressure Relief Valves failing is the same or less than that of hard seat Valves, and that for failed Valves, soft seat Valves typically have failure ratios of proof test Pressure to set Pressure less than that of hard seat Valves.

Julia V. Bukowski - One of the best experts on this subject based on the ideXlab platform.

  • effects of seat width on development of adhesions in stainless steel trim spring operated Pressure Relief Valves
    ASME 2015 Pressure Vessels and Piping Conference, 2015
    Co-Authors: Julia V. Bukowski, Robert E. Gross, William M. Goble, Stephen P. Harris
    Abstract:

    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.Copyright © 2015 by ASME

  • investigation of adhesion formation in new stainless steel trim spring operated Pressure Relief Valves
    Journal of Pressure Vessel Technology-transactions of The Asme, 2014
    Co-Authors: Julia V. Bukowski, Robert E. Gross, William M. Goble
    Abstract:

    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.

  • The Effects of Maintenance Actions on the PFDavg of Spring Operated Pressure Relief Valves
    Volume 6B: Materials and Fabrication, 2014
    Co-Authors: Julia V. Bukowski, Robert E. Gross, William M. Goble, Stephen P. Harris
    Abstract:

    The safety integrity level (SIL) of equipment used in safety instrumented functions is determined by the average probability of failure on demand (PFDavg) computed at the time of periodic inspection and maintenance, i.e., the time of proof testing. The computation of PFDavg is generally based solely on predictions or estimates of the assumed constant failure rate of the equipment. However, PFDavg is also affected by maintenance actions (or lack thereof) taken by the end user. This paper shows how maintenance actions can affect the PFDavg of spring operated Pressure Relief Valves (SOPRV) and how these maintenance actions may be accounted for in the computation of the PFDavg metric. The method provides a means for quantifying the effects of changes in maintenance practices and shows how these changes impact plant safety.

  • investigation of adhesion formation in new stainless steel trim spring operated Pressure Relief Valves
    ASME 2013 Pressure Vessels and Piping Conference, 2013
    Co-Authors: Julia V. Bukowski, Robert E. Gross, William M. Goble
    Abstract:

    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
    ASME 2012 Pressure Vessels and Piping Conference, 2012
    Co-Authors: Julia V. Bukowski, Robert E. Gross, William M. Goble
    Abstract:

    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.Copyright © 2012 by ASME

Sasko Dimitrov - One of the best experts on this subject based on the ideXlab platform.