Grab bars shall be non-rusting and slip resistant, shall be between 11/4 inches and 11/2 inches (11/4" to 11/2" = 32mm to 38mm) in outside diameter, and shall be located 11/2 inches (11/2" = 38mm) clear from the wall. Grab bars shall also meet the definition of structural strength.
521 CMR, § 44.7