I see this buy as a commercial item purchase with incidental installation. It appears must colleagues have set it similar solicitations up as a construction after a review of FBO, but not all some are services others are FAR 12 commercial item purchases.
I'm not sure if because the item is being installed and will be a fixture to real property if that makes it a construction, or some kind of hybrid contract. It seems like overkill to require FAR 36 requirements for a 1-5 day POP.
When in doubt we can check the FAR Part 2 definition for construction, which "...means construction, alteration, or repair (including dredging, excavating, and painting) of buildings, structures, or other real property." The primary purpose of the Government requirement in your acquisition scenario is not to construct, alter, or repair a building but rather to purchase and install an air handler. While it is ultimately a contracting officer decision how to categorize an acquisition, it appears the primary purpose of this acquisition does not place it in the construction category.
Open full Question Details