The faucets on my laundry tub need to be replaced. I'm trying to figure out how to shut of the water supply to the hot and cold lines. There are two valves(maybe?) inline on each of the water lines right above the tub (shown in the attached picture). Are these shut-off valves? If not, what is the purpose of these? I don't see any other shut-offs on these water lines between the tub and the main pipes that go along the ceiling.
Shut off the main valve (stopcock) for the building. If necessary drain pipes. Or
Buy a pipe-freezing kit. Prepare thoroughly. Have a plan B. Work fast.
I agree with the first answer. These are not valves, but plugs. You will have to turn the water off up-stream if not at the main.
These plugs are for convenience if you ever want to branch off from these lines. A threaded fitting can go where these plugs are currently.