Often during inactivity period industrial systems plants could have corrosion due to various factors (oxygen, H2, H2S, acid environment, caustic corrosion, etc.).
The measures to be taken to ensure proper system conservation depend essentially on the duration of the stop. Dry, wet or mixed preservation with inert gases could be carried out. The chemicals used depend on the type of preservation, the complexity of the system and, as mentioned, the duration of inactivity.