Durability exposure category/class for unheated building?

[trwo3]

For an enclosed but unheated building (like a storage building), would you assume the concrete would exposed to freeze/thaw (in colder climates)? So per ACI 318-19 section 19.3.1, would this mean the slab and foundation concrete would be considered F1? Therefore, per table 19.3.2.1, it would require a minimum f'c of 3500 psi, max w/cm of 0.55, and a non-zero level of air content?

Only asking since my company has only specified 3,000 psi concrete or below for these types of buildings and want to make sure that was okay or if we should be increasing it per code.

 

[MotorCity]

Yes, if the building is unheated I would treat it as exposed to freeze/thaw. There is no mechanism to prevent freeze/thaw in an unheated building, even if its enclosed.

 

[dik]

Often interior foundations don't have frost protection.

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-Dik