Engineering notes
Online or line-interactive: a plant room is not a workstation
Line-interactive is enough for a PC. Recorders, PoE and DDCs usually want online double-conversion when the file asks for a clean supply.
The schedule says “3 kVA UPS”. Stores issue a line-interactive rack unit. Fine for a few PCs. A 16-channel recorder, a PoE switch and a DDC — the transfer on mains loss can reboot the recorder. Plant-room files usually say online, double-conversion.
Online costs more, runs warmer, needs cabinet air. Line-interactive is lighter, fine for a small IT stack if the file allows it. Do not put an “office” UPS on a row cooler because the VA matches. Runtime follows the real load, not the nameplate with nothing plugged in.