ASME B18.31.5 is the specific North American standard governing the dimensions, tolerances, and configurations of Inch Series U-Bolts. As a critical part of the ASME "Bent Bolt" family, it provides the engineering requirements for round-bend U-bolts used extensively in support systems for piping, conduits, and structural tubing.

These fasteners are defined by their unified inch threads (UNC/UNF) and are designed to secure cylindrical objects to flat surfaces or other structural members. ASME B18.31.5 ensures that the bend radius, leg length, and thread consistency meet the rigorous safety demands of heavy industrial environments.

The technical focus of ASME B18.31.5 is the radius of the bend and thread engagement. Unlike standard straight bolts, a U-bolt must maintain structural integrity through the cold-bending process. The standard specifies the "Distance Between Legs" ($C$) to match Nominal Pipe Sizes (NPS). For high-temperature or high-pressure piping, the U-bolt acts as a guide or a fixed anchor, depending on the torque applied to the securing nuts.