Leak detection soap bubbles

Immediately after the running test, any compressor intended for toxic, hazardous, flammable, or hydrogen-rich service should be gas tested with an inert gas to the maximum seal design pressure. The test is held at least 30 minutes and the casing and its joints checked for leaks, using a soap bubble method or other suitable means for leak detection. When no leaks are detected, the compressor will be considered acceptable. 

Carbon tetrafluoride may be detected by bubble formation after applying a soap solution to the suspected leak area. Minute leaks may be detected by using a halogen leak detector. If the leak should occur in a cylinder or cylinder valve, move the cylinder to a well-ventilated area and contact the supplier. 

The testing medium should be non-flammable and non-toxic. Leaks may be detected using mild soap solutions or other not-deleterious leak detecting fluids applied to the joint. Bubbles indicate leakage. After leak testing, all soap solutions or leak-detecting fluids should be rinsed of the system with clean water. 

If cylinders are to be brought into the laboratory, they should only be transported on purpose-built trolleys, to which they can be securely chained during transport. Acetylene cylinders must be kept more or less vertical, for reasons discussed in Chapter 2, section 5. The total number of cylinders in the laboratory at any one time must be kept to the minimum possible, especially for fuels and oxidants, and in routine use all cylinders must be securely chained or strapped to a bench or wall. They should be positioned for easy access and so that they will not block a rapid exit. It is perfectly feasible to run two flame spectrometers from a single acetylene cylinder, via a T junction, although individual flash-back arrestors should be fitted in the lines to both instruments. If an acetylene cylinder is used inside the laboratory, it is especially important to check for gas leaks whenever the cylinder head is changed. Don t rely on the smell of escaping gas, which will only detect fairly major leaks. Use of a paint brush and a soap solution is more reliable, as bubbles will be clearly seen if gas is escaping. 

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