I am wondering what the code would be, if there is one, for this situation. I have a low volt sensor wire, two conductor, that is part of an "autofill" system on a swimming pool. It runs in a conduit between the pool and the mechanical room. I would like to run two small vent tubes through the same conduit to vent fumes from the acid and chlorine tanks. There will be no liquid and no pressure in either tube..... Can I do this? Is there a code I can reference when I have the inevitable conversation with an inspector.