RMQSI Answers ForumCategory: 217PlusActive to Dormant Conversion Factors for Storage Reliability
thomas chapman asked 14 years ago

I have a question regarding the conversion of active failure rates to dormant failures rates for deep storage. The RAC Reliability Toolkit: Commercial Practices Edition contains a Table for dormant conversion factors (Table 6.3.4-1 page 178). I was looking at the first column “Ground Active to Ground Passive”. I have been told that these factors for various part types are very conservative. Studies by major defense contractors regarding their product lines in storage environments have resulted in using much lower conversion factors, some as low as 0.01 overall (assuming a weapon system that has a mix of passive and active components such as ICs, diodes, transistors, capacitors, resistors, etc).

Has there been any studies or research done by the RAC that could support updating this table and that lower factors can be used realistically. I am trying to produce an accurate reliability prediction for an air-to-ground missile that is stored either in a Depot or else in a bunker. In the depots, the temperature and humidity are controlled, where as in the bunker the temperature is fairly consistent (50-90 degrees F) but there is no humidity control.

Any information that can support using lower conversion factors would be greatly appreciated.