Method Breathing from a hose attached to an LPG cylinder?

[Syriancel]

In my country, LPG cylinders are available in almost every household for domestic use. I was wondering if inserting the hose into my mouth and breathing would be enough to commit suicide? Do I really need a plastic bag if I have the hose directly in my mouth?

 

[Praestat_Mori]

Logically it won't be enough. Why?

Even if you manage to not breath air through your nose, once you pass out you cannot hold the hose in your mouth anymore. You won't have died yet and you start breathing air again.