M20 Protective Entrance
The M20 External Integrated Protective Entrance (IPE) is used as an air lock to protect the shelter interior and also provides a clean air "shower" to help decontaminate personnel entering the shelters.
- Contains lighting and controls powered by the shelter
- Airflow is from the shelter filtration system
- Occupies no internal space
- Self-supported when erected
- Normal shelter door usage is unaffected
The HDT M20 is a transition enclosure and protected entryway where personnel pause for a specified period before entering to allow the purging of airborne contaminants introduced by opening the outer door. The unit prevents direct vapor transport into the enclosure and ensures that internal pressure is maintained continuously in the enclosure while entries and exits occur. The air lock is purged by the flow of clean air from the main protected enclosure, through the air lock and out a discharge vent on the outer air lock.
Entry/exit is an important consideration for collective protection shelters. It includes both hardware (ventilated air locks) and procedures for transitioning from individual protection to collective protection. Air locks and entry/exit procedures are employed with military collective protection systems because of the need to continue operations while agents may be present in the environment.
The M20 can provide the benefit of helping maintain pressures within a protected area to ensure continuous protection during routine operations.