I routinely use a TIF 8800 combustible gas detector to check for leaks in gas supply lines and some appliance components. On a recent inspection I reported that the natural gas-fueled water heater’s thermostat valve had a leak. I could smell it, and verified that it was there (multiple times) with my gas detector. So, they had a heating and cooling guy come out and he confirmed that it was leaking, but that it was leaking at an “Allowable” rate. My client forwaded me some documents (see attached) he was provided relating to this, and sure enough, Rheem and Ruud say the allowable rate for leakage is 200 cubic cm of natural gas per hour. I hate crying “wolf” at inspections, so the question arises, how to discern 175 cu. cm./hr vs. 250?
As an aside, other documents I found on the web state that there is NO allowable leakage for LP gas.