Chest drain connected to jp

We had a 65 year old female admitted to the floor with a chest tube that the CTS just called a chest drain. It was connected to -40 suction for several days and then he ended up connecting it to a JP bulb. A ways above the bulb there was a little blue clamp that can be turned to off or opened back up. I know JP drains are considered closed systems but since this drain was connected to her chest shouldn't the blue clamp be clamped off before you open the jp to drain it so air doesn't enter her chest? I don't know if all staff caring for her had been doing this.
Hummmm....is the chest tube in the pleural space?

I believe so, yes.

Then I would say yes it should be turned off to the patient when emptying. Weird thing to do though if it is in the pleural space.

I see these quite often where I work and yes you should close the valve when you empty it. We don't allow tech to empty these drains either