So i have seen some moisture wicking through from above.
Concrete safe room ventilation.
High fire rating walls rated at 3 hours with 6 concrete wall thickness safe room considerations.
I am told that concrete gives off moisture for at least a year as it cures.
Safe room must be adequately anchored to resist overturning and uplift.
American safe room manufactures these heavy duty steel ventilation pipes unique and easy bolt on installation with engineered concrete wedge anchors and a thick rubber gasket they feature an armored rain hood that has an removable insect screen and a high security fastener to hold it in place.
A dehumidifier should be run inside the vault room for at least a year or two following construction.
Safe rooms are specially designed structures that offer an enclosed space for people to seek refuge in the event of extreme weather such as tornadoes and hurricanes.
The only place i would be concerned about moisture in the room is the ceiling.
These structures are designed to provide what the federal emergency management agency fema considers to be near absolute protection a term describing the level of protection necessary to significantly lower chances of.
The doors are typically made of high gauge steel tested to resist high wind forces and perforation by windborne debris.
These issues are more difficult for a vault room than for inside a gun safe.
Walls ceiling and doors of the shelter must withstand wind pressure and resist penetration by wind borne debris and falling objects.
The safe room however is all concrete.
Plan for ventilation issues in advance of building.