Leak Testing Flanged Couplings - Video

Quick Tip – Leak Testing Flanged Couplings

There are a lot of flanged couplings used in heat exchanger condenser systems.

Finding vacuum or pressure leaks here is challenging because the leak rate is minimal, turbulence is captured and dissipated in the crevice of the flange and the ultrasound sensor can't get close enough to hear the leak, especially in vacuum.

Here is a tip for finding a suspected leak in this type of coupled pipe.

First, verify that the system is indeed under negative or positive pressure. Using your ultrasound detector scan for leaks.

Then wrap the flange with duct tape, ensuring a good seal all around. If there is a leak, either pressure or vacuum will build inside the tape.

Next, using a small sharp point make a hole in the duct tape around 1/16 of an inch in diameter, being careful not to make the diameter too large. What we are trying to do is transfer the leak turbulence from the middle of the flange to the outer edge of the coupling.

Now, scan the pin hole using the ultrasound detector. If you are close to the pin hole use, either the internal sensor or the flexible wand. If your ultrasound detector accepts multifunctional sensors try measuring the flow across the orifice. The duct tape will create a perfect seal for the mass flow sensor and the leak rate can be quantified in SCFM or SCCM

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