How Pneumatic Tubes Work

Pneumatic Tubes Today

Pneumatic tube transport never died out completely. As long as people used paper documents and photographs, it was still a practical method of transmitting information inside large buildings. The U.S. Central Intelligence Agency (CIA), for example, built a sprawling pneumatic tube system inside its headquarters in Langley, Va., in the 1950s, which transmitted 7,500 documents each day throughout the building's seven floors. It wasn't shut down until 1989, when CIA employees had become so reliant upon e-mail that the tubes were no longer needed [source: CIA].

In the 1970s, companies also began to use heavier, more powerful pneumatic tube systems to transport materials such as machine parts and even gravel inside plants [source: New Scientist]. They're still widely used in industry for such purposes [source: Air Link International]. And banks still have pneumatic tube systems at their drive-up windows, which enable customers to make cash deposits or withdrawals from the comfort of their cars [source: Farber].

More recently, pneumatic tube systems have become popular in hospitals because they can be used to rush tissue and blood specimens from a lab in a distant part of the complex, far faster than a person could do on foot. Stanford University's hospital, for example, has installed a system with 4 miles (6.4 kilometers) of tubes, and uses it to ship 7,000 specimens each day. They've even wedded the 19th-century wonder to 21st-century technology, by equipping the tubes with a digital monitoring system that allows hospital staff to watch the progress of their canister to its destination on a computer screen [source: Wykes].

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