This actually is not what I went in the hall for, this work was over by the Gas Shed outside. I found both argon cylinders empty. I put two new cylinders online. I swapped out an empty cylinder of pre-mix. When the gas system interlock is tripped it shuts off the flow of argon, ethane, and the pre-mix; right at the cylinder manifolds. The carbon-dioxide is not shut off. The pre-mix is no problem, it stops flowing and it then resumes with the same mix ratio. The VDCs will mix till the gas in the supply lines runs down in pressure. So, a slightly different mix of argon/ethane results. We have not seen any noticeable effect from this. Possibly due to the volume of gas in the lines to the Shield Houses being big enough to dilute the change. However, the FPP system will continue to mix, using just the carbon-dioxide. There may be some loss in efficiency, depending on how long the gases are shut down, due to possibly sending straight carbon-dioxide to the straw tube chambers.