You Need A Standby Generator Even If You Have A Continuous Generator
Even if your facility has a continuous generator that is always working, you need a standby generator to pick up the slack if something happens to the continuous generator. When your business relies on having constant power, you need to do everything you can to cover all your bases. That means backing up what you might have already considered a backup.
A continuous generator that is the sole source of power for something should be treated like you'd treat the main power grid.