text: These estimates do not take into account any synergies or efficiencies realized from retrofitting multiple units on a site , as are described in Section 2.5 and 3.5 , or from a combination of technologies , as described in Chapter 5 . Roughly 50 percent of an SCR project man-hours and 40 percent of an FGD project man-hours are for boilermakers .
  
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  These synergies created by multiple retrofits can save as much as 40 % .