Testing

EPCO Zero-Leak Gold plugs were installed into (6) specially designed manifolds. The manifolds tested were made from standard industry Ductile Iron and Aluminum. Three manifolds were made of each material. The (6) manifolds were designed to install (8) different fittings allowing (3) samples of each size to be mounted. Two manifolds were designed with (3) ports on (3) sides and manifold # 3 had (2) ports on (2) sides. The manifolds allowed testing (3) samples of each SAE J1926 port sizes #2, #3, #4, #5, #6, #8, #10, and #12 on (3) manifolds in both Aluminum and Ductile Iron (see detail drawings in Appendix A pages 18-23). The rated working pressure of Ductile Iron is 5000 psi and 3000 psi for aluminum. The goal of the project at MSOE was to establish torque values that successfully pass the 1,000,000 cycle Endurance Test specified in paragraph 8 of NFPA /T2.6.1 R1-1991.

The SAE published values for torque were used as a bench mark for this test. To determine torque values for EPCO Zero-Leak Gold plugs an iteration procedure was established.

Torque values of 25%, 40%, 60%, 70% and 90% of SAE numbers would be tested in succession until successful completion of the NFPA 1,000,000-cycle Endurance Test.

For each test, the torque value was applied to the plugs and the manifold assemblies were plumbed into the impulse chamber and the Rated Fatigue Pressure Endurance Cycle Test was started (see Figure 1. Test Stand Schematic). The Cyclic Test Pressure (CTP) applied was 3688 psi for Aluminum and 6156 psi for Ductile Iron (see Calculations in Appendix A). Pressure waveforms for the 1,000,000 cycle Endurance Test conformed to the characteristics specified by paragraph 8 of NFPA /T2.6.1 R1-1991 (see Appendix A for waveform plots). The basic criteria for the wave shape is maximum rate of pressure rise must not exceed 50,000 psi/sec, the values at MSOE were 49,363 psi/sec for Ductile Iron and 39,769 for Aluminum. The NFPA /T2.6.1 R1-1991, paragraph 8.4.4 states, "The Pulse Duration must be held to 100± 10 milliseconds" and the tests at MSOE ran at 92 milliseconds for Ductile Iron and 98 milliseconds for Aluminum (see Appendix A page 1 and 2 for Ductile Iron and 3 & 4 for Aluminum).

Testing was started and if a failure occurred new O-Rings would be installed and the torque would be increased to the next value. This process was followed until all fittings passed the 1,000,000 cycle Endurance Test specified in paragraph 8 of NFPA /T2.6.1 R1-1991. A failure defined by NFPA /T2.6.1 R1-1991 states " The inability to sustain a given load or to contain pressure in a pressure containing envelope". By the stated definition a leak would cause a failure. The initial test was done with 0.5 ft-lbs. torque applied to each plug. This torque was successful at sealing at static rated pressures, however it failed early into the endurance test.

Initial torque values were 25% of SAE values. There were (5) test torque trials (.5ft-lbs, 25%, 40%, and 2 trials at 60%) until the final torque values values passed the 1,000,000 cycle Endurance Test (final values are listed in Table 1).

The final tests conducted on the plugs were the Proof and Burst Tests. For these tests new Zero-Leak Gold plugs and O-Rings were installed. The Proof and Burst Tests were conducted in accordance with paragraphs 4.1 and 4.2 of SAE J1644 May93. Stated briefly "the roof Pressure Test requires (3) samples to meet or exceed a ratio of 2:1 between proof and working pressure for 60 seconds minimum". The Burst Test requirement states " (3) samples be capable of withstanding the minimum of four times working pressure without failing". All EPCO Zero-Leak Gold plugs passed both the Proof and Burst Tests criteria (see Table 2).