The Construction Specifier, Mar. 2014, by Peter Davis.
http://www.kenilworth.com/publications/cs/de/201403/index.html (jump or scroll to page 34)

"For decades, the U.S. design and construction industry has turned to sprayed polyurethane foam (SPF) to insulate and air seal buildings. SPF can help provide temperature control in various climates, reduce sounds transmitted through the air, and lower construction costs."