limit states in climatic loading class for building envelope

The concept of "limit states" should play a key role in building durability. Limit states means those conditions in which a building ceases to fulfill the function for which it was designed. In structural engineering, loads and load resistance are considered, and limit states such as deflection are specified.

We can apply a similar approach to building durability: We should consider rain, temperature, humidity and the interior climate as environmental loads, and limit states as decay, mold and corrosion.

With building durability we seem not to understand or pay attention to the load part, while complaining about the limit states part.

Hazard Classes

In applying limit states design to durability, building envelopes and mechanical systems should be designed for a specific hygro-thermal region, rain exposure zone and interior climate class.