Effects of Volcanic Ash on Computers and Electronic Equipment

摘要

Computers and electronic equipment are an important component of the infrastructure of our modern environment. It is therefore essential that we know the effects of volcanic ash on such equipment. This paper presents the results of a pilot study to test computers and cooling fans in an ash-charged environment to assess their vulnerability. In the experiment, ash was poured on to computers and cooling fans in a sealed 0.216 m~3 perspex box, with the effects on both the ash and the equipment monitored.Three different types of ash (1996 Ruapehu andesitic ash, Sakurajima andesitic ash and Kaharoa rhyolitic ash) were used in the experiments. In the first experiment each type of ash was photographed by Scanning Electron Microscope (SEM), then passed through the bearing unit of a cooling fan and photographed again afterwards. The bearings within the cooling fan continued to work even after 720 h of testing and there was no significant abrasion of the fan-shaft bearing. The ash was however fragmented, suggesting that the brittle ash shattered to fine 'dust', which caused significantly less abrasion to the bearings or shaft than expected. Three computers were then tested in the sealed box. Ash was introduced at increasing rates to simulate catastrophic entry of ash into a work environment, and computers were tested throughout using the BURNIN~(R) testing programme-Failure times ranged from 100 to 150 h; most failures occurring when humidity was increased by spraying water mist into the airflow. If driedout the computers continued to operate again if failure was not catastrophic. Card slot edge connectors proved to be one of the weakest links, as a bridge of ash formed across the gap. They were also subject to abrasion with some of the gold plating being removed. This did not however cause operating difficulties. The conclusions are that computers are more resilient than originally thought, unless the ash is moist. Simple 'low-tech' procedures should be adequate to protect computers from small amountsof dry and moist ash contamination.