RPM is the acronym used for revolutions per minute. It measures the number of revolutions completed in one minute around a fixed axis, giving the speed of a mechanical component. It is commonly used to describe the performance of automobile engines.
Like most ballparks built from the 1990s onward, Safeco Field is a 'retro-modern' style ballpark that incorporates many of the features of ballparks built in the 1950s and earlier with modern amenities.
Since 2002, the playing field at Rice-Eccles Stadium has been FieldTurf, a next-generation infilled synthetic turf, which was most recently replaced in 2009. When the stadium reopened in 1998, its surface was SportGrass, a hybrid of natural grass and artificial turf.