On: Lead-Free Solder Is Better for You

[mic47]

Depends on whether you breath in and breath into the pipe (which is not ok), or just breath in from the pipe, and breath out elsewhere (you will need some valve that will regulate the flow here).

[prostheticvamp → mic47]

No, I think the issue is that your lungs can’t generate enough negative pressure to respirate effectively through 20m of pipe.

[Dylan16807 → prostheticvamp]

They're not underwater. It doesn't take much pressure just to move air through a tube.