Full definition
Mean Time Between Failures — the fundamental reliability metric for repairable systems, representing the average operating time between consecutive failures: MTBF = Total Operating Time / Number of Failures. Higher MTBF indicates a more reliable system. Expressed in hours. Industrial targets: critical equipment (pumps, compressors, motors) >8,000 hours minimum, world-class >20,000 hours; general equipment >4,000 hours. MTBF is used for: spare parts stocking decisions (lower MTBF = more spares needed), maintenance interval planning, reliability improvement tracking (month-over-month MTBF trends), and new equipment comparison during procurement. Relationship to availability: A = MTBF / (MTBF + MTTR). For example: MTBF = 4,000h, MTTR = 8h → A = 99.8%. Limitation: MTBF assumes a constant (random) failure rate and does not model wear-out patterns — for components with predictable wear-out (belts, seals, bearings), Weibull analysis and age-based replacement are more appropriate. Per IEEE 1413, MIL-HDBK-217 (electronics), and ISO 14224 (petroleum/petrochemical reliability data collection). Data sources: plant CMMS records, manufacturer published data, and industry databases (OREDA for offshore, IEEE 493 for electrical).