Need to calculate the load capacity for a drop ceiling frame.

[chet everett]

Code for any modern lighting troffer installation includes SUPPORTING the light fixture itself with structural wire that is anchored into whatever the ceiling grid is suspended from -- otherwise there would be a risk of the light fixture getting knocked out of the grid and then exposing live electrical connections. If you look above the grid you'd see this:



Similarly, if you were to look above the grid you'd see that HVAC outlets / vent grills are attached to the ductwork itself, with is going to be supported by an elaborate series of supports that are attached the structure like this --

[Sherifftruman]

For lights, in my area they're typically still actually sitting on the grid and are the actually screwed to the grid and the grid has wires attached at corners or a separate wire is attached on two corners to the fixture itself, it's mostly to keep the lights from falling in a seismic event so the extent of support will vary. The lights are heavy and they will definitely cut you as I found out early in my career. Yes, HVAC ducts are supported but the grills are still usually sitting on the grid as well as a few pounds of load from the flex drop. Also, much of the code around this has changed the last decade or so so older stuff is not even hung that much. Either way, it's best to check with the manufacturer to see what they reccomend.