Unknown Construction 
AIR provides the following code for unknown construction:
Construction Code 


Unknown 
The construction class is not known. If the construction and occupancy codes for a location are both "Unknown," Touchstone assigns the occupancy code "General Commercial."
The damage functions for unknown construction are the weighted average of the known construction damage functions. Touchstone uses an exposureweighted average at the state level to capture the variability in building stocks at this geography. Note that the unknown damage function varies by occupancy class code.
For an exposure of known occupancy but unknown construction and height, Touchstone uses a damage function that is a weighted average of the damage functions for the same occupancy class corresponding to all combinations of construction and height classes. 
In some models, the construction and occupancy class code combination 100300 is invalid, and Touchstone remaps this combination to 100311. However, for exposures in South America, the construction and occupancy class code combination 100300 is valid, and Touchstone does not remap this combination. 
© 2018 AIR Worldwide. All rights reserved. Touchstone 4.0 Updated June 13, 2018 