Testing For Corrosion Protection
- Testing for Corrosion Protection
So, how do you know if your tank is protected? It only takes a minute to
As stated in the section on cathodic protection, if the voltage of steel is
-0.85 volts or greater, it is protected. It takes a voltmeter and a copper
sulfate electrode to take the reading. It can be taken by a propane gas
technician with a basic understanding of cathodic protection. If the reading
greater than -0.85 volts, you can assume that the tank is protected at the
location where the reading was taken on the date it was taken. If the
below -0.85 volts, the anode installed on the tank either has been consumed,
the tank is connected to the house utilities without a dielectric union or
wire has been disconnected. Occasionally, there is a problem with the
equipment or contact to the tank. It takes practice and experience to find
answer to these problems. There are other causes for a low reading which
require a cathodic protection technician or a corrosion engineer to
Contact to the tank can be made on any metal connected to the tank. This
the gauging device, the regulator, the pressure relief valve or the
The dome would not be a good contact point as it does not make good metal
contact with the tank.
Some tank installers are able to route the anode wire into the dome or even
attach a separate test lead wire from the tank and run it into the dome.
can be made on either of these wires. I would recommend taking at least four
readings around the tank.
As A Homeowner, I would like to see:
A copy of the readings with a written report showing when
how the readings were taken.
A drawing to accompany the report.
The qualifications of the person who tested my tank.
This done once a year.