In the following cases all pneumatic vibrators can work in open-air applications.

Pneumatic vibrators should not be installed in the liquid immersion places. If the vibrator can be placed in exposed to the liquid (or other rain drops), you should take the following steps:
Vibrator should be installed so that the exhaust port of the exhaust pipe with silencer down or mounted on the exhaust port of the exhaust pipe of the exhaust vent line downward. This prevents liquid or dust from entering.
If the vibrator is exposed to liquid, and who can not take these steps, install a muffler and ensure 0.1-1bar (15-30PSI) continuous outlet pressure, prevent liquid inflows.
Note: In the case of dust, liquids or other particles (concrete powder, caustic solution) may enter the exhaust port of the muffler is not installed, do not start the vibrator.