Guidelines for Fire Protection in Chemical, Petrochemical, and Hydrocarbon Processing Facilities: Page 218

Chapter 7, Fire protection Fundamentals, page 218, section, Example; There are three lines for calculation of total foam concentration for stock requirements which is based on provided formulas on the top of example context on this page. If you look at to the second line of calculation it shows (3 hose streams x 500 gpm/stream x 3% foam concentrate x 30 minutes =135.)  This result should be 1350 gallons and as total result in last line the " Total base quantity of foam concentrate (gallons) should be = 2640".