Full definition
The expected operating duration of a power transmission belt before replacement is required, measured in hours. Typical design life targets: V-belts 15,000-25,000 hours, timing belts 10,000-25,000 hours, Poly-V belts 20,000-30,000 hours, automotive serpentine (EPDM) 60,000-100,000 miles. Factors that reduce life: under- or over-tensioning (each reduces life 30-50%), misalignment (>0.5° halves life), undersized pulleys (increases flex fatigue), high ambient temperature (each 10°C above 30°C halves life per Arrhenius rule), oil contamination (softens CR/EPDM, reduces grip), and overloading. Factors that extend life: proper tension monitoring, laser alignment, clean environment, adequate ventilation, and quality belts from reputable manufacturers. Per ISO 1081 and ARPM design life methodology. Document installation date and hours for trend analysis to predict replacement before failure.