1. Date of download: 6/3/2016 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 Contour plot of MTBF (yr) assuming a two-parameter Weibull distribution Figure Legend:

2. Date of download: 6/3/2016 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 Hazard plot for η=1.5 yr when β = 0.8, 1, and 1.5 Figure Legend:

3. Date of download: 6/3/2016 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 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. Figure Legend:

4. Date of download: 6/3/2016 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 R p versus time-in-service (years) for the SRS used valve proof tests Figure Legend:

5. Date of download: 6/3/2016 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 The cumulative maintenance time distribution for time-in-service for used valves Figure Legend:

6. Date of download: 6/3/2016 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 Box and whisker plots for time-in-service of failed and passed SRS used valve proof tests Figure Legend:

7. Date of download: 6/3/2016 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 Contour plot of the likelihood function, L, using SRS proof test results Figure Legend:

8. Date of download: 6/3/2016 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 Updating η based on SRS used valve proof tests Figure Legend:

9. Date of download: 6/3/2016 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 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. Figure Legend:

10. Date of download: 6/3/2016 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 Risk, inspection cost, and total cost of inspection for extending maintenance intervals Figure Legend: