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RUL

Plain-Language Definition

Remaining Useful Life — the estimated number of years a building component or piece of equipment can continue to function adequately before it needs replacement. A critical input for CAPEX planning.

Technical Context

RUL is estimated based on: original design life, current condition, maintenance history, operating environment, and manufacturer data. Typical design lives: flat roof 20-25 years, chiller 20-25 years, lift 25-30 years, boiler 20-25 years, AHU 15-20 years, fire alarm panel 15-20 years, generator 25-30 years, transformer 30-35 years. RUL = design life - age ± condition adjustment.

Why It Matters

RUL drives CAPEX planning. A chiller with 3 years RUL needs to be budgeted for replacement now. RUL assessment is part of every PCA (Property Condition Assessment). Buildings with many systems at or past end of useful life require significant CAPEX investment — this affects acquisition pricing and lease negotiations.

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