Why does the Life safety branch take precedence over the critical branch? And why call it critical when it is truly life supporting over all else? Id think ventilators would need power first and before all else.
Hospitals require a large amount of emergency power because lives depend on the ability of many services in the hospital to remain functional at all times. As described previously, code requires that the emergency power is segregated into four different branches. When the generator starts up, the power branches are started sequentially to prevent the generator from being overloaded by all systems starting at once. The life safety branch starts first, followed by the critical power, the equipment, and finally the X-ray branch. Now that the X-Ray is served by a UPS, there will be no problems with starting this last.