AS/NZS2312 - Surface Specific Atmospheric Corrosivity Category

[rowingengineer]

NZ interior environment - warehouse without a cavity or insulation - discussion microclimate.

Is anyone classifying interior areas as Damp and C3 in cold areas? due to possible dew points a few times a year?

 

[m_struct]

Sounds like there is potential for condensation.

HERA R4-133 touches on that. Refer below.

 

[rowingengineer]

We were reading that as well however it seems to indicate a cavity and then bring in an additional somewhat engineer judgement item. I can see a microclimate on the girts and purlins but I don't see it for the main structure.

 

[m_struct]

A couple classification for interior
- hidden from view (50+ years to first maintenance)
- exterior surfaces - walls and roofs - inside vapor barrier but possible condensation issues due to dew point

NZS 2312.1 section 1.2, gives guidance on situations when corrosion protection not required. SNZ 3404:2018 Table 2 states surface specific atmospheric corrosivity categories - interior damp is generally C3.

My understanding is that the exterior surfaces is subject to some engineering judgement, but the above (HERA R4-133) gives some guidance and further classification of elements (and requirements) based on location, ie - inside thermal envelope.

Good question. Curious to hear what corrosion protection other engineers are specifying for these interior conditions in both commercial and residential.