Which method is best to check for leaks in a fumigant application rig?

• A. Smelling for gas
• B. Listening for hissing noises
• C. Striking a match
• D. Spraying with soap solution and checking for bubbles

Answer: (D)

Detecting leaks with a soap solution provides a clear, visual way to confirm where gas is escaping without creating ignition risks. When the fumigant system is pressurized, any leak will cause the soap to bubble at that spot, so you can pinpoint the exact location of a problem on joints, fittings, hoses, or seals. This method is safer and more reliable than relying on smell, which may be faint or absent for some fumigants, or listening for hissing, which can miss small leaks or be hard to hear. Striking a match or using any flame near fumigants is dangerous and can ignite vapors. To test, spray or brush a soap solution over all connections and fittings while the rig is pressurized, then watch for bubbles. If bubbles appear, tighten or replace the faulty part and recheck to confirm the leak is gone.