Reliability Payoff

By Harold W. Williams

The topics featured in this issue include reliability prediction addressed at the design stage, reliability assessment from performance of delivered product, and a system reliability perspective for this millennium.

Also, readers will note the advertisement of Reliability Analysis Center introduces a tool for reliability prediction.

My contemplation of these writings and others submitted for upcoming symposiums has moved me to suggest the following. This past January we crossed a chronological intersection. At each intersection the R & M professional may do well to determine whether to continue on the current path or alter course. You have made a choice as an individual. Fortunately, you can always make an adjustment. If the course you are on does not include the resolve to disclose to the recipients of your analyses the economic benefit of your recommendations; do consider an adjustment.

I recently accomplished a Red Team review of design concepts for proposed new electronic plumbing systems. The targeted market is the commercial plumbing industry where purchased quantities will run in the hundreds and thousands. The design and specialty engineering analyses had been assembled to support the decision making. The modern technology of "no-touch washroom" systems is very attractive and especially helpful in hospital facilities. I was impressed with the features and the technical issues addressed. Reliability and maintainability were mentioned frequently as important considerations, but there were no trade-offs of component selections and the life cycle cost differentials. That shortcoming seriously hampered decision making. I decided to spend about two hours gathering some facts and accomplishing comparative life cycle cost analysis. The system design concepts included: a thermostatic mixing valve, choose among three models; a sensor, choices were LED, PSD, or Dual Beam; solenoid valve, choose among two models; and power source, AC with surge protection or battery.

I quickly obtained failure rate and delta costs on the components, and typical repair costs. Then, it was a simple task to compute life cycle costs. The result of the calculations placed in a spreadsheet disclosed the following:

I have simplified the above by omitting environmental issues which were important considerations to be supplied to applications engineers but of minor importance in decision making. Also, I have omitted the extension to actual market projections which should be included ( a simple task).

Given the above information, the decision making was straightforward and earned the favor of the Chief Engineer, CFO and CEO.

The reliability and maintainability cost tradeoffs are important elements of the system engineering final report. See to it that the reliability payoff is clearly presented. Then, you can be sure that top management understands your contribution. Reliability doesn’t cost. It pays!