The fixture unit of the section. 
   Namespace:   Autodesk.Revit.DB.Mechanical  
  Assembly:   RevitAPI  (in RevitAPI.dll) Version: 2015.0.0.0 (2015.0.0.0) 
  Since:  2013 
Syntax
Remarks
 In one section, all section members have same fixture unit. Fixture Unit is a number. The unit type is UT_Number.