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Forum: Reliability & Maintainability Questions and Answers

Topic: Reliability & Maintainability Questions and Answers

Topic Posted by: Reliability & Maintainability Forum ( )
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998

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Posted by: Barry Ma ( )
Organization:Anritsu Company
Date posted: Tue May 15 21:33:00 US/Eastern 2001
Subject: PRISM vs. 217
"It would be more proper to say that PRISM is the successor to the 217", Gary Sunada described when replying a post of "Calculated Failure Rate vs. Field Failure Rate" May 14. MIL-HDBK-217 has many shortcomings and should be updated. People have been talking about this for years. Now the RAC has presented the PRISM to the Reliability world. Can we have more detailed explanations on the improvements made from 217 to PRISM like "What and how were those shortcomings overcome by PRISM?" For example, one of the critics to 217 is that it is based on component failure data. But the component reliability has been improved a lot over the last three decades. The component failure no longer constitutes a major reason for modern electronic system. Many other failure modes were not incorporated into 217. If this is true, how does PRISM handle the issue? Thank you.


Subject: PRISM vs. 217
Reply Posted by: David Dylis ( )
Organization: Reliability Analysis Center (RAC)
Date Posted: Mon May 21 9:37:25 US/Eastern 2001
PRISM since its release in March of 2000 has gained wide acceptance in the R&M user community and is quickly becoming the industry standard for system reliability assessments. Probably the best testimonial to PRISM acceptance is its use in the user community. The RAC has identified that the following types of systems are being analyzed with PRISM: automotive systems, aerospace systems, satellite systems, radars, computers, transmitter/receivers, cryogenic cooler electronics, fuel cell electronics and down-hole oil drilling electronics to name a few. PRISM has also been specified and recommended as the prediction methodology to be used in several DoD system procurements.

It is often difficult to instill change away from methodologies that have been utilized for decades, however the inadequacies that exist within these predecessor methodologies have helped the community embrace PRISM with much enthusiasm. PRISM deviates from traditional reliability prediction methodologies by allowing a user to factor in component, assembly and system test data and addresses system level design and manufacturing processes to refine a system prediction. These design factors, known to impact field reliability, have been previously ignored. In addition, the newly developed PRISM component and system assessment models address not only operational aspects but also non-operational and/or dormant aspects of a part or system. These models based on RACís most current reliability data will be updated routinely as new data is collected whereby keeping the models and the PRISM approach current with the state-of-the-art. For more information on PRISM or to download a demo of the PRISM software, please visit the RAC PRISM web site:

RAC is also providing the opportunity for organizations to resell the PRISM software and/or integrate the PRISM methodology into their products. Thank you for your interest in PRISM and if you have any questions, please contact me.

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