25 Jan Airlock and Pressurization in the Hindenburg
Hindenburg? What has to do with cleanrooms?
Airlock and Pressurization in the Hindenburg. When talking about cleanrooms, topics like these are very common. But, are them related to the unfortunate zeppelin Hindenburg? In this post, we will figure out how.
A brief history
The Hindenburg was a German commercial passenger-carrying rigid airship, or commonly called, zeppelin type, in honour of its inventor Ferdinand von Zeppelin. Rigid airships consist of a structural framework usually covered in a doped fabric containing a number of gasbags or cells containing a lifting gas. This gas has a lower density than the air.
Hydrogen in the Hindenburg was the gas used as a lifting gas. Very light, but very flammable gas. Initially, Helium was selected for the lifting gas because it was the safest to use in airships, as it is not flammable.
However, helium was relatively rare and extremely expensive as the gas was available in industrial quantities only from distillation plants at certain oil fields in the United States. By comparison, an industrialized nation could produce hydrogen cheaply. And as hydrogen is lighter than helium, also provided more lift.
Passengers had all the comforts available for luxury travels: gourmet meals served on fine china in the dining room, fashioned cocktails in the bar, and enjoy incredible views through the large observation windows.
A tragic fire accident caused the destruction of the Hindenburg on May 6, 1937. Definitively, travelling with 140,000 m³ of hydrogen above the head was not a good idea.
The smoking lounge
During the 2oth century thirties, smoking was the icon of modernity and intensively promoted by advertisements. It could be sound strange nowadays but just we have to remember that prohibition of smoking in planes was applied just during the nineties.
In the 1935 Popular Mechanics magazine we could find advertisements showing famous professional athletes promoting a smoking brand:
German engineers probably coincided to avoid a smoking lounge in an airship full of hydrogen. But probably as well, it should be a ‘must-have’ specification, according to the social customs.
To avoid the risk of fire, passengers could only smoke in this specific lounge. An attendant guarding the door prevented breaking that rule and collected the passenger’s gaslighter.
Moreover, the lounge design included an airlock to generate a physical separation between the rest of the airship. We can see it in the deck B layout:
Additionally, the Hindenburg’s smoke room and bar design included positive pressure (if you are curious about the pressure you can look at this link).
In the pharmaceutical industry, we design positive pressure to avoid contamination entering from a less contaminated room. Nevertheless, in the Hindenburg, the positive pressure intended to avoid that hydrogen enters into the smoking-room.
So, in a certain way, airlock and pressurization in the Hindenburg are related to a modern cleanroom.
Just a final curiosity. A non-well out cigarette was not the cause of the fire. Probably a hydrogen leakage together the presence of static charge was.