Partial Safety Factors (PSFs) are scaling factors which are used to modify the input parameters to a deterministic fracture mechanics assessment in order to consider the effects of variability or uncertainty in the values of the input parameters. BS7910 and SINTAP have adopted the technique, both of which use the First Order Reliability Method (FORM) to derive values for PSFs. The PSFs are tabulated, varying with the target probability of failure, p(F), and the Coefficient of Variance (COV) of the variable. An accurate assessment of p(F) requires a probabilistic method with enough simulations. This has previously been found to be time consuming, due to the large number of simulations required. The PSF method has been seen as a quick way of calculating an approximate, conservative value of p(F). This paper contains a review of the PSF method, conducted using an efficient probabilistic method called the Hybrid probabilistic method. The Hybrid probabilistic method is used to find p(F) at a large number of assessment points, for a range of different PSFs. These p(F) values are compared to those obtained using the PSF method. It is found that the PSF method was usually, and often extremely, conservative. However there are also cases where the PSF method was non-conservative. This result is verified by a hand calculation. Modifications to the PSF method are suggested, including the establishment of a minimum PSF on each variable to reduce non-conservatisms. In light of the existence of efficient probabilistic techniques, the non-conservatisms that have been found in the PSF method, coupled with the impracticality of completely removing these non-conservatisms, it is recommended that a full probabilistic assessment should generally be performed.
Skip Nav Destination
ASME 2010 Pressure Vessels and Piping Division/K-PVP Conference
July 18–22, 2010
Bellevue, Washington, USA
Conference Sponsors:
- Pressure Vessels and Piping Division
ISBN:
978-0-7918-49255
PROCEEDINGS PAPER
Analysis of the Partial Safety Factor Method Using Probabilistic Techniques
B. A. Lindley,
B. A. Lindley
Serco TAS, Risley, Cheshire, UK
Search for other works by this author on:
P. M. James
P. M. James
Serco TAS, Risley, Cheshire, UK
Search for other works by this author on:
B. A. Lindley
Serco TAS, Risley, Cheshire, UK
P. M. James
Serco TAS, Risley, Cheshire, UK
Paper No:
PVP2010-25312, pp. 431-440; 10 pages
Published Online:
January 10, 2011
Citation
Lindley, BA, & James, PM. "Analysis of the Partial Safety Factor Method Using Probabilistic Techniques." Proceedings of the ASME 2010 Pressure Vessels and Piping Division/K-PVP Conference. ASME 2010 Pressure Vessels and Piping Conference: Volume 6, Parts A and B. Bellevue, Washington, USA. July 18–22, 2010. pp. 431-440. ASME. https://doi.org/10.1115/PVP2010-25312
Download citation file:
17
Views
Related Proceedings Papers
Related Articles
Uncertainty of Integral System Safety in Engineering
ASME J. Risk Uncertainty Part B (June,2022)
Deterministic and Probabilistic Fracture Mechanics Analysis for Structural Integrity Assessment of Pressurized Water Reactor Pressure Vessel
J. Pressure Vessel Technol (June,2016)
Applications of Probabilistic Fracture Mechanics to Offshore Structures
Appl. Mech. Rev (February,1988)
Related Chapters
A Bayesian Approach to Setting Equipment Performance Criteria (PSAM-0438)
Proceedings of the Eighth International Conference on Probabilistic Safety Assessment & Management (PSAM)
Establishing Unmanning Criteria for a Jacket Structure on the NCS
Ageing and Life Extension of Offshore Facilities
A PSA Update to Reflect Procedural Changes (PSAM-0217)
Proceedings of the Eighth International Conference on Probabilistic Safety Assessment & Management (PSAM)