R-value (insulation) as ASHRAE 90.1 and the IECC prescribe U-values. However, R-value is widely used in practice to describe the thermal resistance of insulation products, layers, and most other parts of the building enclosure (walls, floors, roofs). Other areas of the world more commonly use U-value/U-factor for elements of the entire building enclosure including windows, doors, walls, roof, and ground slabs. The SI (metric) unit of R-value is whereas the I-P (inch-pound) unit is For R-values there is no difference between US customary units and imperial units, so the same I-P unit is used in both. Some sources use ″RSI″ when referring
American College of the Building Arts also specialized courses in drawing, design, materials science and construction management. ACBA maintains a low student-to-faculty ratio to ensure the highest standards of quality in its programs. The Byrne-Diderot Library is a major research resource for students and faculty. The library houses a specialized collection of books, periodicals, newspapers and audiovisual materials in the building, visual, decorative and liberal arts. The library's main collection contains over 6.500 items. The D.A.R. Special Collections room contains another 500 rare books, catalogs and periodicals, as well as examples of historical tools and 19th century Charleston iron work. American College of the Building Arts