Useful Life

The useful life (UL) of an asset is the estimated length of time during which the asset is likely to be able to deliver a satisfactory level of service.

International Infrastructure Management Manual

The International Infrastructure Management Manual states that "useful life" may be expressed as either:

• The period over which a depreciable asset is expected to be used, or
• The number of production or similar units (i.e. intervals, cycles) that is expected to be obtained from the asset.

CPA Australia valuation and depreciation guide

The CPA Australia valuation and depreciation guide suggests that there is an asset management/engineering definition of useful life and an accounting one.

• Engineering Definition - The period from original commissioning to the time of decommissioning, including a number of expected major renewals.
• Accounting Definition - The period in which the asset is expected to be available for use or the number of production or similar units expected to be obtained by the entity.

General Notes

The useful life of an asset is not necessarily equivalent to its physical life or economic life, a number of other factors may result in an assets useful life being reduced, including:

• Obsolescence
• Changes in community expectations
• Increased demands on capacity
• New legal requirements

Reviewing Asset Useful Lives

Whenever an asset class is revalued the appropriateness of the useful lives applied to the assets within that class should be considered.

Factors that could be considered when reviewing asset useful lives, include:

• The useful lives adopted by other organisations;
• The average condition of assets nearing the end of their expected useful lives;
• The typical design life (with era of construction practices/assumed workmanship/ quality)
• The percentage of assets requiring renewal before reaching the end of their estimated useful lives.

LGAM Useful Life Table

The useful life of most assets will depend on a wide range of environmental factors, but it is usually necessary to adopt a standard useful life for a range of asset types for asset management and accounting purposes. It would make life much easier if the state or federal governments published a list of default asset useful lives for Councils to use in the absence of better information, but with the notable exception of South Dakota in the United States, a quick internet search seems to suggest that this isn't a high priority for state governments around the world.

The table below was LGAMs attempt to compile a list of realistic asset useful lives.

Asset Type	Typical UL	Range
Asphalt Footpath	30 years	20-50 years
Asphalt Overlay	20 years	20-25 years
Backhoe	6 years	5-7 years
Boardwalk	30 years	25-30 years
Boat Ramp	30 years	30 years
Bollard	20 years	15-30 years
Box Culvert	90 years	80-100 years
Brick Paved Footpath	50 years	30-80 years
Bridge	80 years	25-100 years
Building Envelope	60 years	45-75 years
Building Fire Services	40 years
Building Fitout	30 years	20-45 years
Building Mechanical Services	30 years	25-35 years
Bus Shelter	20 years	20-40 years
Computer	3 years	3-4 years
Concrete Floor	100 years
Concrete Footbridge	80 years	25-200 years
Concrete Footpath	60 years	20-120 years
Concrete Road Bridge	90 years	30-100 years
Crane	10 years	5-10 years
Culvert	65 years	50-80 years
Dam	60 years
Fence	10 years
Flagpole	40 years	20-60 years
Floor Coverings	20 years	5-40 years
Front End Loader	7 years	5-10 years
Grader	10 years	5-10 years
Gravel Footpath	12 years	5-50 years
Gravel Resheet	12 years	5-20 years
Guardrails	20 years
Headwall	80 years	70-100 years
Kerb & Channel	60 years	20-120 years
Lifts & Transport Services	25 years
Litter Bin	20 years	20-30 years
Mower	7 years	5-10 years
Park Bench	25 years	15-50 years
Passenger Vehicle	6 years	2-10 years
Playground Equipment	15 years
Pumping Station	50 years
Reinforced Concrete Stormwater Pipe	100 years	80-120 years
Retaining Wall	25 years
Road Formation	1000 years	150-∞ years
Road Pavement	80 years	20-120 years
Roller	6 years	5-7 years
Roof	50 years	15-90 years
Runway	30 years
Service Reservoir	50 years
Sewer Maintenance Hole	80 years
Sewer Pipe	75 years	65-80 years
Skate Park	50 years	50-80 years
Shade Sail	15 years	15 years
Solar Panel	30 years	25-40 years
Splitter Island	50 years	50-70 years
Sprayed Seal	15 years	12-30 years
Steel Footbridge	60 years	25-100 years
Stormwater Pipe	60 years	60-120 years
Stormwater Pit	90 years	70-150 years
Street Lighting	30 years	20-50 years
Tennis Court	12 years	7-30 years
Timber Decking	30 years	15-60 years
Timber Footbridge	40 years	25-100 years
Tractor	8 years	5-10 years
Traffic Sign	15 years	10-30 years
Traffic Signals	25 years	15-40 years
Treatment Plant	50 years
Truck	7 years	5-10 years
Two Coat Seal	15 years	10-50 years
Valve	10 years
Water Meter	10 years

Related Pages

• Lifecycle Cost Analysis
• Remaining Useful Life
• Residual Value

References

• Infrastructure Asset Useful Lives - 2009 (LGA.SA)
• Infrastructure Asset Useful Lives - 2014 (LGA.SA)
• Boroondara City Council Asset Management Plan for Roads
• South Dakota Municipal Asset Useful Life Table
• Road Safety Engineering Risk Assessment Part 4: Treatment Life for Road Safety Measures (Austroads)
• Lifecycle Cost Guidelines for Sport and Recreation Facilities (Western Australian Department of Sport Recreation)
• Tweed Shire Council Drainage Assets Management Plan
• Asset Lives - Felix Schrodinger's Blog
• Levels of Service & Asset Lives - Felix Schrodinger's Blog
• The Gold Book (SA Department of Education and Child Development)
• Standard Life Comparison Roads and Stormwater
• CPA Australia valuation and depreciation guide
• Fanny Mae Estimated Useful Life Tables
• IPWEA Practice Note 12 - Useful Life of Infrastructure
• Local Government & Municipal Knowledge Base

External Links

• Google Search