Vault door

A Vault requires proper sealants against radiation and other hazardous elements that may be created in the event of a nuclear war, to properly protect its inhabitants. Vault-Tec, in their infinite wisdom, used a number of different door models in their shelters, the most common being the tried-and-true Seal-N-Safe Vault Door Model No. 343 (denoted as such in the Vault 15 townmap).

Seal-N-Safe Vault Door Model No. 343
Most common model, this door was first used in the demonstration Vault beneath Los Angeles. It had a smooth outer surface and opened outwards, rolled to the side by an extending mechanical arm. It was a very compact design, usually followed by a long air lock, ending in a high security door, with two layers of steel and a slab of lead in the middle.

East Coast model
A far more crude model was used in the East Coast Vaults, this particular one opened inwards, with the use of a hydraulic arm. This manner produced an extreme amount of unhealthy grinding noise during opening, easily damaging one's eardrums.