You can use the fire extinguisher and can put it back as long as the pressure gauge needle is in the green zone. If it goes to the red zone, this means the pressure is less and you need to replace it. In the latter case, tell your real estate management to replace it. Ideally, they should check it on a regular basis. If the needle is in the green zone, just put back the safety pin in its place and hang it at the same place.
For the fire alarm glass, please get it repaired through your house owner/real estate management. They will come and re-set it again with a new glass. If the glass is already broken, it may not set-off an alarm if you try to activate it again.
drsam,
You can use the fire extinguisher and can put it back as long as the pressure gauge needle is in the green zone. If it goes to the red zone, this means the pressure is less and you need to replace it. In the latter case, tell your real estate management to replace it. Ideally, they should check it on a regular basis. If the needle is in the green zone, just put back the safety pin in its place and hang it at the same place.
For the fire alarm glass, please get it repaired through your house owner/real estate management. They will come and re-set it again with a new glass. If the glass is already broken, it may not set-off an alarm if you try to activate it again.