1. 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): doi: /
Figure Legend:
Contour plot of MTBF (yr) assuming a two-parameter Weibull distribution

2. 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): doi: /
Figure Legend:
Hazard plot for η=1.5 yr when β = 0.8, 1, and 1.5

3. 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): doi: /
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.

4. 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): doi: /
Figure Legend:
Rp versus time-in-service (years) for the SRS used valve proof tests

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): doi: /
Figure Legend:
The cumulative maintenance time distribution for time-in-service for used valves

6. 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): doi: /
Figure Legend:
Box and whisker plots for time-in-service of failed and passed SRS used valve proof tests

7. 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): doi: /
Figure Legend:
Contour plot of the likelihood function, L, using SRS proof test results

8. 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): doi: /
Figure Legend:
Updating η based on SRS used valve proof tests

9. 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): doi: /
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.

10. 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): doi: /
Figure Legend:
Risk, inspection cost, and total cost of inspection for extending maintenance intervals