July 18, 2007

Topical reading: 'The Works' by Kate Ascher

In case you don't have a copy of the excellent book "The Works: Anatomy of a City" by Kate Ascher, the executive vice president for infrastructure at New York City's Economic Development Corporation, here are a few facts from her chapter on NYC's steam system:

- NYC's underground district steam system is the biggest in the world, with some 30 billion pounds of steam flowing each year at speeds up to 75 mph.

- The New York Steam Company started in 1882 and Con Edison today still uses that basic framework (with improvements.) Steam makes up about 7 percent of ConEd's revenues. (ConEd also has a web page about it's steam system.)

- Steam is produced at several plants in the city, where water is heated in boilers at temperatures around 1,000 degrees. It's carried in pipes four to 15 feet underground, though near the Metro North tunnel, it's as deep as 30 feet. Most of the pipes are made of steel, "though many of the older cast iron pipes remain in service. These older pipes are vulnerable to cracking, and are often coated in asbestos -- which is not problematic as long as they remain undisturbed."

- In August 1989, three people died near Gramercy Park as a result of a steam explosion. She writes of the 1989 incident:

The cause of that explosion, like many others, was a phenomenon known as 'water hammer,' which results from the condensation of water inside a steam pipe. In this case, steam personnel had allowed water to accumulate in a pipe they had turned off for service; when the steam valve was reopened the 400-degree steam hit the relatively cool water, with explosive results.

July 18, 2007 09:40 PM in Architecture, Transportology

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