Publications Details
The effect of smoke from plastics on digital communications equipment
Smoke from plastics can cause immediate problems in electrical equipment in the form of shorting and increased leakage currents, as well as long-term corrosion (metal loss). The short-term problems can be especially serious for critical control instrumentation such as that found in nuclear reactors or telecommunications systems. The US Nuclear Regulatory Commission and Sandia National Laboratories are sponsoring a program to determine the modes and probabilities of digital equipment failure during exposure to smoke and up to 24 hours after the exposure. Early tests on computer systems have shown that the most common immediate problems are temporary and are likely to be caused by increased leakage currents. High-voltage circuits are especially vulnerable since the charged particles in smoke are drawn to those surfaces. To study failure probabilities, smoke exposure tests with real-time measurements will be carried out to determine how the electrical properties of the environment are affected by smoke concentration and content. Digital communication cable will be included in the tests because temporary shorts that cannot be detected through dc measurements may cause interruptions in communications between computers. The reaction of the equipment to changed electrical properties of the environment will be modeled. Equipment that can be used for testing and modeling is being solicited.