ACI 306R-10 requires the ambient air temperature surrounding newly cast concrete to be approximately 55 degrees. Pevarnik Bros., Inc., using best practices, encloses the surrounding area with air barriers and heat the same to ensure that the concrete stays approximately 55 degrees during the protection period. The top 2 photos above are of an enclosure we did to pour large piers for the VIM/VAR building at Latrobe Steel in January of 2008. They turned out perfect with durable, strong concrete. In the winter of 2016, PBI poured approximately 110,000 s.f. of slab on metal deck at Excela Health in Latrobe. A. Martini, the General Contractor, enclosed the building and heated the floors from under the decks. The result was excellent, flat, durable concrete floors for the new medical facility.