Chronicle of an older diver

Air Pressure September 27, 2011

Around this time of year I need to blow the water out of my underground sprinkler system so it doesn’t burst during the winter freeze-up. I used to use a company to do it, until figuring out that I could save the money by doing it myself, with a return on investment of 1 year. The process is pretty simple, hook up a regular air-tool compressor to the outside hose bib, shut off the inside tap (lest my toilets explode), crank up the pressure on the compressor to 120psi (safe on my system, your mileage may vary) and program the controller for 1 minute on, 9 minutes off, and cycle it twice.

After finishing on Sunday I disconnected the hose from the compressor without bleeding it off. The hose then whipped around my porch for the next couple of minutes, whacking my ankle (without injury) in the process. This is food for sober thought when thinking about the pressures used in your typical scuba shop, with AL80s at 3000 psi, and compressors that have a safety shut off at 5,000. If a 120 psi hose can whip around menacingly, you can imagine what would happen at 3-5,000 psi.

Most of us learn just how dangerous a scuba tank can be. A recently fatality in Florida is yet another example. Let’s be careful out there!