The Sanborn Map Company helped fire insurance companies set rates in the late 19th and early 20th centuries with these detailed maps of each built structure, its use, dimensions, height, building material, and other relevant features (fire alarms, water mains and hydrants, for example).
To find your Philadelphia location within the Sanborns, start with this Graphic Map of Volumes, which will identify the volume covering your location. Each Sanborn volume has its own front-matter Volume Key with a map identifying map pages covering groups of city blocks. The Volume Key will also provide a graphic explanation of map symbols,and it will often include an index of business establishments.
