In the next few weeks, your wiki will be migrated to a domain. Learn more here.

Vault blast door

From The Vault - Fallout Wiki
Jump to: navigation, search

Unlike internal doors, Vault blast doors[1] 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.[2] The only known vault to have been hit by a nuclear weapon is Vault 87 and the blast damaged the door beyond repair.[3]

Seal-N-Safe Vault Door Model No. 343[4]

Sleep in quiet comfort knowing that our impenetrable vault doors can withstand a direct hit by an atomic bomb with only a projected 2% failure rate.

Vault-Tec exhibit messages

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.[5]

The central element of the assembly is, of course, the gear-shaped door. Four yards (3.6m)[6] 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.[7]

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.[8]

An integral component of the door is the airlock, overpressurized to keep the contaminats out of the Vault. This long hallway's floor was covered in grating, coupled with a series of wall-mounted vents for decontamination.[9] 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.[10]

Advanced Vault door

Vaults also used superior models, like the advanced Vault doors.[11] 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.[12]

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.[13]

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.[14] 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.[15]

Additional protective measures

Dome elevator

The dome was an additional protective measure designed for Vault 111. 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 in 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.[16]

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.

Behind the scenes

  • An interesting thing to note is that 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. However the newer model would allow the door to be opened even if rubble had fallen near the door on the outside.


  1. Vault Dweller's Survival Guide: "The simulation will now start. After a briefing by the Vault Overseer as to your immediate task, you will appear outside the Vault Blast Door."
  2. Museum of Technology vault system tour: "Sleep in quiet comfort knowing that our impenetrable vault doors can withstand a direct hit by an atomic bomb with only a projected 2% failure rate."
  3. Vault 87 Overseer's terminal: "...The main door to Vault 87 is damaged beyond repair and we are detecting extremely high levels of lethal radiation outside and in the entry tunnel.."
  4. Named in the image.
  5. Fallout Bible 6: "1e. Vault doors were in the tanker in San Fran, from which vault are they, and who brought them onto the ship?
    They are unmarked models, planned for shipment somewhere up or down the West Coast. The "Vault Doors" were used for more than just Vaults, however, so the door may have been intended for some other facility. It's most likely just there because of designer caveat/designer privilege/game logic - the designer probably just needed something to fill up space in the tanker, and the door looked like good "junk.""
  6. Vault Dweller's Survival Guide p.1-1—1-2: Important Vault Statistics
    Vault Number ............................13
    Starting construction date .........August 2063
    Ending construction date ..........March 2069
    Starting Budget .........................$400,000,000,000
    Final Budget, with interest ........$645,000,000,000
    Total number of occupants .......1,000 (at capacity)
    Total duration ...........................10 years (at capacity)
    Number of living quarters .........100 (hot bunking required if at maximum capacity)
    Door thickness ..........................4 yards, steel
    Earth coverage .........................3,200,000 tons of soil, at 200 feet
    Computer control system .........Think machine
    Primary power supply ...............Geo-thermal
    Secondary power supply ..........General Atomics Nuclear Power backup systems
    Power requirements .................3.98mkw/day
    Stores .......................................Complete construction equipment, hydro-agricultural farms, water purification from underground river, defensive weaponry to equip 10 men, communication, social and entertainment files (for total duration)
  7. Fallout intro
  8. Prop behavior.
  9. Fallout intro
  10. Fallout intro
  11. Fallout Shelter
  12. Fallout 4 trailer
  13. Behavior of the prop.
  14. Airlock appearance.
  15. Fallout Shelter fortified Vault door
  16. Fallout 4 trailer