0
Research Papers: Operations, Applications & Components

Evaluating Risk and Safety Integrity Levels for Pressure Relief Valves Through Probabilistic Modeling

[+] Author and Article Information
Emily M. Mitchell

Dept. of Biostatistics and Bioinformatics,
Emory University,
Atlanta, GA 30322

Robert E. Gross

Site Infrastructure Reliability Engineering,
Savannah River Nuclear Solutions,
Aiken, SC 29808

Stephen P. Harris

Computational Sciences,
Savannah River National Laboratory,
Aiken, SC 29808

Contributed by the Pressure Vessel and Piping Division of ASME for publication in the Journal of Pressure Vessel Technology. Manuscript received April 9, 2012; final manuscript received October 10, 2012; published online March 18, 2013. Assoc. Editor: Allen C. Smith.

J. Pressure Vessel Technol 135(2), 021601 (Mar 18, 2013) (8 pages) Paper No: PVT-12-1040; doi: 10.1115/1.4007959 History: Received April 09, 2012; Revised October 10, 2012

The probability of failure on demand (PFD) for spring-operated pressure relief valves (SORVs) is estimated by applying the Fréchet and Weibull probability distributions using proof test data from the United States Department of Energy's Savannah River Site (SRS) in Aiken, South Carolina. The data can be accessed through the Center for Chemical Process Safety (CCPS) Process Equipment Reliability Database (PERD). The probability distributions enable the evaluation of risk, estimation of ANSI/ISA-84.00.01 Safety Integrity Levels (SILs), and the impact of potential modifications of the maintenance plan. Current SRS practices are reviewed, and recommendations are made for risk-based adjustments to the maintenance plan. Subsets of valves are identified in which maintenance times can be extended and in which increased safety margins may be needed.

FIGURES IN THIS ARTICLE
<>
Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

(a) Conventional spring design steam service valve; cap and bonnet removed, (b) valve body and inlet nozzle; very few deposits on the seating surface and no cuts, (c) Inside the valve bonnet; corrosion evident but not much loose debris, and (d) Spring, spring washers, disc holder and disc, stem, sleeve guide, and stem retainer

Grahic Jump Location
Fig. 2

Ratio versus date by working fluid

Grahic Jump Location
Fig. 3

Ratio by working fluid

Grahic Jump Location
Fig. 4

Maintenance time distribution (years) over all working fluids

Grahic Jump Location
Fig. 5

Time (years) by working fluid

Grahic Jump Location
Fig. 6

PFD for the Fréchet and Weibull distributions for air, gas, and steam services

Grahic Jump Location
Fig. 7

PFD for the Fréchet and Weibull distributions for liquid services

Grahic Jump Location
Fig. 8

Weibull fit for the probability of failure, air, gas, and steam services combined

Grahic Jump Location
Fig. 9

Fréchet fit for the probability of failure for the liquid service group

Grahic Jump Location
Fig. 10

Risk versus cost by maintenance time (years) for air, gas, and steam service combined

Grahic Jump Location
Fig. 11

Risk versus cost by maintenance time (years) for liquid service

Grahic Jump Location
Fig. 12

PFDavg and SIL by maintenance time based on bench proof tests

Grahic Jump Location
Fig. 13

PFDavg and SIL by maintenance time based on forecasted field values

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In