Minn. R. 4626.1340
FLOORS, WALLS, AND CEILINGS; UTILITY LINES. 6-201.12
A. Utility service lines and pipes must not be unnecessarily exposed. B. Exposed utility service lines and pipes must be installed so they do not obstruct or prevent cleaning of the floors, walls, or ceilings. C. Exposed horizontal utility service lines and pipes must not be installed directly on the floor.