CRE (Hong Kong Civil Service Exams) case studies
CRE · Put your knowledge to work in context.
The Certified Reliability Engineer (CRE) is a professional credential for people who specialize in improving the reliability, maintainability, and safety of products, systems, and processes. According to ASQ, the certifying body, a CRE focuses on identifying potential failures, optimizing performance, and ensuring compliance with quality and reliability standards. The CRE case studies are 5 cases and about 4,911 words.
1Accepting a Pump Module on a Zero-Failure Demonstration Test
Your company must accept a new pump module from a supplier who warrants an MTBF of 2,000 hours, and the contract calls for demonstrating that value at 80% one-sided confidence under a constant failure rate assumption. The agreed plan is time-terminated: run three units, permit zero failures, and stop when accumulated unit-hours reach the precomputed requirement.
927 words, about 5 min2Corrective Maintenance Downtime and a PM Interval Trade
A plant runs 14 identical packaging lines under a service contract that specifies corrective maintenance mean downtime no greater than 2.0 hours and a 90th-percentile downtime no greater than 4.0 hours per repair. Last quarter the CMMS logged 40 corrective work orders and 96 hours of line downtime.
979 words, about 5 min3An RPN Cutoff That Spends the Safety Budget on a Cosmetic Display
A six-person FMEA team is reviewing a large-volume infusion pump before design freeze. The facilitator applies the plant's standard rule: any failure mode with RPN of 100 or more receives a corrective action, and any mode below 100 is closed with no action.
1,028 words, about 5 min4Reliability Growth: Cumulative Versus Instantaneous MTBF
Three prototype units of a new servo drive are on a reliability growth test. At 4,800 accumulated unit-hours the team has logged eight failures, at cumulative test times of 120, 340, 780, 1,250, 1,900, 2,700, 3,600 and 4,500 hours.
980 words, about 5 min5Sizing a High-Temperature Trip Against a LOPA Target
A chemical reactor's high-temperature trip is being designed to protect against a runaway reaction with a catastrophic consequence. The plant's LOPA sets a tolerable frequency of 0.0001 per year for the consequence.
997 words, about 5 min