LIFT: The sprayed polyurethane foam resulting from tying together the perimeter of adjacent passes of foam in a specific area, as shown in Figure A below. A lift is defined by its thickness. Multiple lifts over the same area may be needed to achieve the final foam thickness. For example, a one inch lift of foam can be installed over a 20 x 20 ft area, and then a second lift of foam 1.5 inch thick can be installed to the same area to create a final installed thickness of 2.5 inches. For small areas, such as between framing members, a lift of foam is synonymous with a pass of foam per Figure B below.
LIFT FIGURE A: Lift definition for low-slope roofing
LIFT FIGURE B: Lift and pass are synonymous for SPF insulation applications