Hydraulic Fitting Performance: Burst Testing, Tubing Limits, and Connection Strength

Hydraulic fitting performance is proven by how the complete connection behaves under pressure, not by the fitting body alone. Hydrostatic burst testing is one way to show whether the fitting, tube, and assembly method can tolerate pressure beyond normal operating conditions.

What Burst Testing Shows

In a burst test, pressure is increased until the weakest part of the assembly fails. A strong fitting should hold while the tube or another limiting element reaches its burst point. This kind of test helps separate a connection that merely fits together from one that has real pressure margin.

Tubing Can Be the Limiting Factor

One common test setup uses a stainless male connector on 1/2 inch tubing with a 0.065 inch wall. In that style of test, the tube may fail before the fitting body does, showing that tubing material, wall thickness, and preparation are part of fitting performance.

Pressure Margin Matters

Results such as assemblies holding several times above the tubing burst pressure, up to around 20,000 psi in the reported test example, demonstrate why pressure rating should be treated as a system property. The fitting, ferrules, tube, and installation all contribute to the final margin.

Checks Before Substitution

When replacing a fitting, confirm the fitting family, tube outside diameter, wall thickness, material, pressure rating, and assembly method. A part that looks similar may not deliver the same burst performance if the tube or connection geometry is different.