Customers ask us all the time whether DK-Lok tube fittings really measure up to Swagelok. We'd rather show you than tell you. DK-Lok put that question to a third-party test, and A-Best Industrial Inc. Fittings, Valves, and Tubing has the full results available for you to download.
Download the ASTM F1387 Quality & Performance Test report (PDF)
What was tested
ASTM F1387 is the standard that sets the performance requirements for mechanically attached fittings used in piping and tubing systems. DK-Lok tested all 14 possible combinations of intermixed DK-Lok and Swagelok components (nut, back ferrule, front ferrule and body) in five common fractional tube sizes:
- 1/4" x 0.049" wall
- 3/8" x 0.049" wall
- 1/2" x 0.065" wall
- 3/4" x 0.095" wall
- 1" x 0.109" wall
All testing was witnessed and certified by TÜV Rheinland, an independent third party. No failures were observed.
The tests
The intermixed assemblies went through the ASTM F1387 examination of specimen, pneumatic proof, hydrostatic proof, impulse, flexure fatigue, tensile, hydrostatic burst, repeated assembly and rotary flex tests, plus the supplemental thermal cycling and vibration tests. A few highlights from the report:
- Proof tests run three times. The pneumatic and hydrostatic proof tests were each run three times, with the fittings taken apart and remade between runs. The standard only requires one run.
- Hydrostatic burst. Assemblies held four times the tube's rated working pressure for one minute. When pressure was raised to rupture, every failure happened in the tube, not the fitting.
- Rotary flex. 1,000,000 cycles at 500 psi under a locked-in bending moment, with no leakage.
- Flexure fatigue. 30,000 cycles at the tube's full rated working pressure, with no leakage.
Backed in writing
Based on these results, DK-Lok publicly guarantees DK-Lok tube fitting assemblies intermixed with Swagelok components of the same size and material, when properly assembled and used according to the DK-Lok catalog, as a safe and leak-tight seal, as if they were its own. The warranty letter is included in the report.
This guarantee covers DK-Lok with Swagelok only. It does not extend to other brands. See our Swagelok, Parker, Hy-Lok & Superlok cross-reference for how we quote other brands.
Talk to us
A-Best Industrial Inc. Fittings, Valves, and Tubing is an authorized DK-Lok distributor in Southern California. Questions about intermixing, sizing or certs? Call 310-833-3353 or email sales@abesttube.com. We're open Monday–Friday, 8:00 AM–5:00 PM Pacific, with after-hours emergency service.
DK-LOK is a registered trademark of DK-Lok Corporation. Swagelok is a registered trademark of Swagelok Company.