NFPA 855 Series: What an AHJ learned from the McMicken Energy Storage Facility Owned by Arizona Public Service Co.
We always try to learn lessons. What worked well, what didn't work well. McMicken showed us that a clean agent type fire protection system alone is not adequate. We need something else. We need sprinklers. If we're going to be in an occupiable space, once again, we know that sprinklers don't control the thermal runaway, so all we're really doing is cooling it. Now, sprinkler water, as well as the water mist system, is really good about keeping vapors down, which is another thing that we're working on here in the valley with one of our battery installations. But sprinklers alone are not going to control the thermal runaway. It's going to do its thing until it's done.