Remaining Life Assessment (RLA)

How Much Service Life Is Still Available? 

Every critical component has a finite service life. 

During operation, time, temperature, pressure, and repeated operating cycles gradually consume the life of materials and components. 

For aging equipment, the important question is not simply how long the equipment has been in service, but: 

“How much of its available service life has already been consumed?” 

Remaining Life Assessment (RLA) focuses specifically on quantifying accumulated life consumption and estimating the remaining service life of critical components under defined operating conditions. From Service Exposure to Life Consumption 

RLA establishes the relationship between the service exposure of a component and the amount of life that has been consumed. 

The assessment may consider: 

• Operating hours 

• Temperature exposure 

• Pressure exposure 

• Number of operating cycles 

• Thermal cycles 

• Load cycles 

• Material properties 

• Historical operating conditions 

These parameters provide the basis for determining how operating exposure has contributed to the consumption of component life. 

Future Operating Life 

Remaining life is dependent on how the equipment is expected to operate in the future. 

For this reason, RLA may establish remaining life based on defined future operating conditions, such as: 

• Expected operating temperature 

• Expected operating pressure 

• Operating hours per year 

• Expected startup and shutdown frequency 

• Expected load cycles 

• Planned operating profile 

A change in future operating conditions may change the projected remaining life and may require reassessment. 

RLA Assessment Methodology 

A focused RLA follows a direct engineering sequence: 

Define Service Conditions → Establish Life Basis → Quantify Life Consumption → Determine Life Limit → Calculate Remaining Life 

The assessment uses applicable material data, operating history, component characteristics, and engineering life criteria. 

The result is a defined estimate of the remaining service life under the assessed operating conditions. 

Standards & Methodologies 

RLA may be performed using applicable engineering standards and established life assessment methodologies. 

• API 579-1 / ASME FFS-1 

• ASME Standards 

• API Standards 

• DNV/Industry Best Practices 

The Value of Remaining Life Assessment 

RLA provides a focused engineering basis to: 

• Quantify consumed service life 

• Estimate remaining service life 

• Identify the applicable life limit 

• Establish remaining operating hours or cycles 

• Evaluate the effect of future operating conditions 

• Support long-term equipment planning based on quantified remaining life 

Measure What Has Been Consumed. Know What Remains. 

Remaining Life Assessment focuses on one fundamental engineering question: 

How much service life remains in the component under defined operating conditions?