This book examines in great detail the D-B and IPD methods, while touching on D-B-B and CM project deliveries. In this vein, the discussion regarding IPD is a variation from ASHRAE Technical Committee TC 7.1, Integrated Building Design (IBD), with the focus herein on HVAC-Led IPD Opportunities by consulting engineers and mechanical contractors.  This IPD variation is also described later in the book as a 21st-century version of what was 20th-century D-B project delivery although D-B project delivery is still widely used.