Vault door

When Vault-Tec constructed their vaults, they made sure that their inhabitants were well protected from outside threats. One of the key pieces of engineering that protected the dwellers was the vault door.

Standard door
A typical door used in the vaults, composed of two pieces that connect and seal (with the use of special interlocking cones) when the door closes. An emergency override handle is placed above the connection seam. Under normal circumstances, when a hatch is locked, only an experienced locksmith could lockpick the hatch. Each door is operated by hydraulic motors that effect 3300 lbs of pressure when operating the door.

The doors are designed with three safety features. The first is a caution zone marked by yellow lines on the floor. The second is an automated system that reverses the door if it detects an obstruction, and attempts at closing the door a few moments later. If the obstruction remains under the door, it will continue repeating this motion until powered off or the door finally closes. The final feature is a power box next to the door, which can be used to shut off electricity to the bulkhead and seal it. Under normal circumstances, the lamps on the power box are green. If the power to the door is cut using the switch, they glow red.

Interior doors
The vault door is a type of electro-mechanical door used in the Vault-Tec vaults for creating physical barriers between corridors, rooms, and stairways. The hatch is a heavy steel door, of either one or two pieces, supported in a heavy steel frame built into a wall and powered by concealed powerful hydraulic motors.

Security door
This model is identical in function and safety features to the door above, except there is a centrally painted white vertical band with a stop sign and the words "No Access - Authorized Personnel Only". There are downward pointing chevrons above and below the text.

Maintenance hatch
This is a one-piece hatch. Hydraulic motors swing it 90 degrees on a hinge when opening. On one side of the hatch, there are two circular indicators. When the hatch is closed, both indicators display diagonal red lines on a white background. As the hatch is opening, the indicators display OPEN in red text on a white background, while the other shows STAND BACK in red text on a black background.

Vault blast door
Unlike internal doors, vault blast doors are designed not only to keep contaminants and radiation out but also to protect the occupants from danger. These massive doors are one of the iconic elements of a vault, their gear design instantly recognizable in the wastelands.

These vault doors had a projected 2% failure rate, in case of a direct hit by a nuclear missile. The only known vault to have been hit by a nuclear weapon is Vault 87 and the blast damaged the door beyond repair. There are two known examples of vault blast doors being damaged by smaller-yield explosives: Vault 15, which has a No. 343 model door that was blown off by a shaped charge, and Vault 79, which has a nine cog model door blown off by several bricks of C4.

'Seal-N-Safe' Vault Door Model No. 343
The No. 343 was the basic vault door model, first used in the demonstration vault. The efficiency of the design led to it being used in numerous vaults, including Vault 8, 12, 13, 15, and other installations. They were usually shipped assembled and installed whole.

The central element of the assembly is, of course, the gear-shaped door. Four yards (3.6m) thick at its thickest point and made out of heavy duty steel, they are designed to withstand a lot of punishment. The twelve cogs of the door lock into recessions cut into the frame, providing stability and support for the massive frame. The door was shaped like a cork, using friction wedge design to plug the door frame and and create an excellent seal.

When the right password was input, the door would be removed from the frame by a hydraulic press, placing it on the external track. A separate mechanical arm would extend from the external assembly, lock into the recessions placed on the back of the door, and smoothly slide it into a reinforced container on the side.

An integral component of the door is the airlock, overpressurized to keep the contaminants out of the vault. This long hallway's floor was covered in a grating, coupled with a series of wall-mounted vents for decontamination. It terminates in a security door leading into the vault. Unlike other models, this one opened sideways, with interlocking steel plates on both sides and a slab of lead sandwiched between them for added protection.

East and West Coast
Vaults also used superior models, like the advanced vault doors. Thinner and with nine cogs instead of twelve, it was fitted into the door frame snugly and was opened inwards, rather than outwards, by a large hydraulic arm suspended from the ceiling inside the airlock. The door had a clearance of 4.52 meters (14 feet and 10 inches), allowing easy entrance and exit. The door ensured that the airlock would remain overpressurized and keep contaminants out of the controlled environment of the vault.

When activated, the airlock would initiate a purge cycle, equalizing pressure through the door-mounted valve. The safe distance for anyone in front of the vault door was 10 meters (33 feet). Once the cycle was completed, the door would be engaged by the mechanic arm, pulled back onto the internal track, and rolled sideways. The mechanism relied entirely on the mechanical arm, rather than a hydraulic press as in the No. 343 model.

The airlock was also different. People entering the vault would do so through a trench flanked with railings, observed from the control station by security personnel. The airlock was equipped with ceiling-mounted sprinklers, for easy decontamination. The advanced model could also be further reinforced, with the resulting fortified vault door offering top-notch protection against assailants trying to get into the vault.

Such models were used in the East Coast and the Mojave Wasteland vaults; these particular ones had a larger opening diameter and was much thicker than the Seal-N-Safe 343. Usually mounted near the door is a warning light and siren which are both turned on during the first few seconds of the door's opening or closing cycle. One installation has the ability to mount security cameras beside the door. The East Coast model is opened from the inside using a large mechanical arm mounted to the vault entrance's ceiling. When the door control panel is used to open the door, the arm swings down and pulls the door inward and onto a gear rack built into the entrance floor, allowing the door to roll aside. Inside and outside the vault, there is a control panel that activates the vault door from either side, and the controls can be locked with a password. It is assumed that the password is a voice command, as there appears to be a microphone and speaker on the console.

Commonwealth
A different model was used in the Massachusetts region, and also in Vault 118 in Maine. This model is very similar to the doors seen in the Capital Wasteland and Mojave Wasteland regions. When properly maintained and serviced, the door has a dark grey base and has a bright yellow center and outer rim. The vault number is neatly drawn in black. On the rear-side of the door are black-and-yellow warning symbols, and a light-bearing the text "clear" mounted beside the door. Within the base is a yellow purge valve with a hydraulic tank. It is one of the only doors so far known to have text on the door. Vault 111 in particular has an elevator, an additional protective measure as a nuclear blast wave would pass over it. leading to the surface entrance to the vault. The dome was an additional protective measure designed for the vault. Placed on the top of the hill overlooking the neighborhood, the dome would protect the interior of the vault by causing the blast wave to pass over it, without concentrating at any one point. In the center of the dome was a secondary blast door that protected the lift leading inside the vault. Notably, it appears that the dome has an emergency interface panel, which allows the blast door to be open manually using a crank and a wheel. It is a large convex structure and has a vault-shaped elevator and blue and grey paint throughout the structure. It also bears yellow pipes, gas tanks, warning lights, black plates dotted throughout, and a red in-take valve. From the inside and outside, the vault door is controlled by a control panel, but unlike its East and West Coast counterparts, the Commonwealth control panel requires to be connected to the adapter plug of a Pip-Boy 3000 Mark IV to unlock the controls. Also, unlike the Capital and Mojave Wasteland vault doors, a large mechanical arm rolls the door to one side instead of the door simply rolling to the side by itself.

Blast door
Vault 8 was one of the few vaults equipped with an additional door built into the side of a mountain. Embedded into a concrete wall reinforcing the slopes, the massive door was designed to seal the access corridor to the internal vault door. The circular reinforced concrete frame provided additional protection and ensured an equal distribution of weight in case of a natural catastrophe. Vault 76 had a similar design.

Fallout Shelter
Every vault in Fallout Shelter, has the same standard model of door. When the vault door is upgraded to Level 2, the nine cog model is used.

Behind the scenes
The No. 343 model would protect better against a nuclear blast. The nine cog model rests in its recessions without mechanical stops to prevent it from collapsing inward under the shockwave. By comparison, the No. 343 has a friction wedge and stops for the cogs. As a result, the shockwave would press it harder against the frame and complete the seal, unless the entire door frame fails. The newer model would allow the door to be opened even if rubble had fallen near the door on the outside.