The type and use of leak detection fluids in the gases industry has evolved significantly in the last decade. Recent new concerns involving the current crop of leak detection fluids in general use today is set to trigger changes in industry standards and business practices for medical gas firms. This article looks at the evolution of leak detection fluids, these new and evolving concerns, and what actions firms need to consider in the near future to stay in compliance.
History
Not all that long ago the most prevalent leak detection fluid (LDF) in use was good old liquid Ivory Soap® and water. Medical gas firms purchased bulk quantities of the soap or a competitive product and diluted it with drinking water at their facility. Since the components were relatively cheap, most firms tended to apply the fluid liberally when checking cylinders, and at best, did a quick rinse with water. Rarely were the cylinders adequately washed off.
In the late 1990s problems with this leak checking practice began to surface. Very few firms had a set procedure for mixing the soap solution with water, so the concentration of soap and water had a tendency to vary considerably. While this issue could have been easily rectified, the Food and Drug Administration (FDA) became aware of the issue and got involved.
The FDA contended that firms had no data proving that a liquid soap solution effectively detected leaks, despite the fact that LDF standards did exist. The most common LDF standard is a military specification – MIL-PRF-25567E. A second specification for LDF can be found in section 6-12.2 of NFPA 52, which covers leak testing of compressed natural gas (CNG) vehicular fuel systems. Both of these specifications contain specific performance criteria for leak detection, and commercial leak detection fluids are tested by the manufacturer to verify they meet one or more of these LDF standards.
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