rvice problems. The night was quiet; work in the building was carried out routinely. It was going to be a boring evening. At 12:30, just after midnight, a relatively inconsequential piece of power equipment in the building's subbasement cable vault shorted and spit a few errant sparks into the air around it. It caused no alarms Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Telephony Telephony because it didn't actually fail. One of the sparks, however, fell on a piece of insulation and began to smolder. The insulation melted and began to burn, changing from a smoldering spot on the surface of a cable to a full- blown fire. Soon the entire cable vault was aflame. Cables in a central office leave the cable vault on their way to upper floor switching equipment through 6-inch diameter holes cored in the concrete floors of the office. The fire burned its way up the cables, exited the cored holes, and spread from floor to floor. Soon all of the lower floors of the building were engulfed, and New York Telephone was on its way to hosting the single worst disaster that any American telephone company has ever experienced. Emergency service vehicles converged on the building. They evacu- ated everyone inside and began flooding the lower floors with hundreds of thousands of gallons of water. Smoke and steam billowed up and out of the structure (see Figure 3-1), severely damaging equipment on the upper floors that had not, as yet, been affected by the fire. Figure 3-1 Smoke and steam billow from the 2nd Avenue central office. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Telephony Chapter 3 Two days later, the fire was finally out and telco engineers were able to reenter the bui