Both stainless and carbon steel LOKRING® fittings are qualified to the requirements of the ANSI/ASME B31 pressure piping codes for pressure and fatigue design and materials of construction. Extensive mechanical and environmental testing has demonstrated the mechanical and sealing integrity of the LOKRING® connection in a wide range of applications and environmental conditions.
We have created a detailed technical guide for Designing ASME B31 Pressure Piping Using Lokring Fittings with ESP Technology.
The 1/2″ NPS stainless steel test fitting was subjected to torsional loading high enough to twist the pipe in a spiral without leakage of the joint. Afterwards during hydraulic testing, the pipe ruptured at 22,000 psi (1,497 bar).
The 2″ NPS carbon steel coupling above has been deflected to 3x the yield strength of the matching pipe without leaking. The performance of this fitting in severe bending, fatigue and vibration loads are comparable or superior to a socket weld fitting.
The metal-to-metal LOKRING® seal remains intact when subjected to extreme thermal loads, including fire (above). Both stainless and carbon steel LOKRING® fittings are qualified to the Exxon API-607 Rev 4, fire test standards. Stainless steel fittings are also qualified to F1387 (U.S. Navy) fire test standards. Both are widely used on volatile and flammable services.
Are you responsible for designing pressure piping systems according to ASME B31? Contact your authorized LOKRING® distributor for support in designing ASME B31 pressure piping using LOKRING® Elastic Strain Preload (ESP®) fittings.