Date of download: 10/15/2017 Copyright © ASME. All rights reserved. From: Evaluation of Maintenance Intervals for Spring-Operated Relief Valves Using a Risk-Based Inspection Technique J. Pressure Vessel Technol. 2012;134(6):061601-061601-7. doi:10.1115/1.4005940 Figure Legend: Contour plot of MTBF (yr) assuming a two-parameter Weibull distribution

Date of download: 10/15/2017 Copyright © ASME. All rights reserved. From: Evaluation of Maintenance Intervals for Spring-Operated Relief Valves Using a Risk-Based Inspection Technique J. Pressure Vessel Technol. 2012;134(6):061601-061601-7. doi:10.1115/1.4005940 Figure Legend: Hazard plot for η=1.5 yr when β = 0.8, 1, and 1.5

Date of download: 10/15/2017 Copyright © ASME. All rights reserved. From: Evaluation of Maintenance Intervals for Spring-Operated Relief Valves Using a Risk-Based Inspection Technique J. Pressure Vessel Technol. 2012;134(6):061601-061601-7. doi:10.1115/1.4005940 Figure Legend: The impact of a single pass or fail proof test result on the current estimate of eta (η=20) for various weight factors: λ=0.1, 0.2, 0.3, and 0.4(β=1.5). Note that: (1) for passed inspection at 5 yr, η=20 yr (essentially no change); (2) for failed inspection at 5 yr, η=13 yr.

Date of download: 10/15/2017 Copyright © ASME. All rights reserved. From: Evaluation of Maintenance Intervals for Spring-Operated Relief Valves Using a Risk-Based Inspection Technique J. Pressure Vessel Technol. 2012;134(6):061601-061601-7. doi:10.1115/1.4005940 Figure Legend: Rp versus time-in-service (years) for the SRS used valve proof tests

Date of download: 10/15/2017 Copyright © ASME. All rights reserved. From: Evaluation of Maintenance Intervals for Spring-Operated Relief Valves Using a Risk-Based Inspection Technique J. Pressure Vessel Technol. 2012;134(6):061601-061601-7. doi:10.1115/1.4005940 Figure Legend: The cumulative maintenance time distribution for time-in-service for used valves

Date of download: 10/15/2017 Copyright © ASME. All rights reserved. From: Evaluation of Maintenance Intervals for Spring-Operated Relief Valves Using a Risk-Based Inspection Technique J. Pressure Vessel Technol. 2012;134(6):061601-061601-7. doi:10.1115/1.4005940 Figure Legend: Box and whisker plots for time-in-service of failed and passed SRS used valve proof tests

Date of download: 10/15/2017 Copyright © ASME. All rights reserved. From: Evaluation of Maintenance Intervals for Spring-Operated Relief Valves Using a Risk-Based Inspection Technique J. Pressure Vessel Technol. 2012;134(6):061601-061601-7. doi:10.1115/1.4005940 Figure Legend: Contour plot of the likelihood function, L, using SRS proof test results

Date of download: 10/15/2017 Copyright © ASME. All rights reserved. From: Evaluation of Maintenance Intervals for Spring-Operated Relief Valves Using a Risk-Based Inspection Technique J. Pressure Vessel Technol. 2012;134(6):061601-061601-7. doi:10.1115/1.4005940 Figure Legend: Updating η based on SRS used valve proof tests

Date of download: 10/15/2017 Copyright © ASME. All rights reserved. From: Evaluation of Maintenance Intervals for Spring-Operated Relief Valves Using a Risk-Based Inspection Technique J. Pressure Vessel Technol. 2012;134(6):061601-061601-7. doi:10.1115/1.4005940 Figure Legend: Snapshot of a 56 K Monte Carlo series of η updating for simulated time to failure (β=2.3 and η=21 yr) using (a) the current valve maintenance plan. (b) the current valve maintenance plan extended by 1 yr. and (c) the current valve maintenance plan extended by 2 yr.

Date of download: 10/15/2017 Copyright © ASME. All rights reserved. From: Evaluation of Maintenance Intervals for Spring-Operated Relief Valves Using a Risk-Based Inspection Technique J. Pressure Vessel Technol. 2012;134(6):061601-061601-7. doi:10.1115/1.4005940 Figure Legend: Risk, inspection cost, and total cost of inspection for extending maintenance intervals