Design working life
What it means precisely
Section titled “What it means precisely”The design working life is the period the structure is designed for. It affects:
- how the actions are taken: over a longer period a larger extreme value has to be allowed for,
- the durability requirements: corrosion protection, material choice,
- the maintenance expectations.
For buildings it is typically several decades; shorter for temporary structures, longer for major works.
What it does not mean
Section titled “What it does not mean”Not a guarantee
Section titled “Not a guarantee”The design working life is not a warranty from the contractor or the designer. It is a design assumption, not a contractual undertaking.
Not an expiry date
Section titled “Not an expiry date”A structure does not automatically collapse when the design working life is up. The assumption is that it will certainly comply until then — after that a review is warranted.
Not independent of maintenance
Section titled “Not independent of maintenance”The assumption includes that the structure is used and maintained as intended. If that does not happen, the life is shortened.
What it means for a light gauge steel building
Section titled “What it means for a light gauge steel building”Corrosion protection
Section titled “Corrosion protection”The coating is chosen to suit the life and the environment of installation. Zinc coating.
A dry structure
Section titled “A dry structure”The life of a steel frame is effectively that of the building, if it stays dry. The risk is not in the material but in the moisture. Corrosion and service life.
Replaceable layers
Section titled “Replaceable layers”Some elements of the build-up have a shorter life than the structure: coverings, seals, finishes. A good design makes them replaceable without opening up the structure.
What matters in this for the owner
Section titled “What matters in this for the owner”The life does not come by itself: it takes maintenance, and the documentation has to survive. If we do not know what is in the wall, maintenance cannot be planned either. Maintenance and durability.
The point
Section titled “The point”The design working life is an assumption, not a promise. The building will last as long as design, construction and maintenance together allow.