Two weeks after the fire, a team of four investigators converged on the scene, which was still in almost the same shape it was in immediately after the fire. During the next four days, the team visited fifty separate fire scenes, recording, photographing, and videotaping the evidence. We had initially planned to visit 100 sites, but because of the uniformity of the data obtained, the team members concluded that viewing an additional fifty sites was not likely to reveal anything new. Although the project was carried out entirely at the expense of the investigators, the civil authorities, especially the Bureau of Alcohol, Tobacco and Firearms and the City of Oakland Police Department, provided invaluable support in terms of manpower and access. Briefly summarized, what was learned is that bedsprings that appear to be melted are common in nonaccelerated residential structures that burn to completion.
Melted copper is also common.
Crazed glass is not a useful indicator of fire behavior, as it can only be produced when hot glass is rapidly cooled. Any time a study produces results that cause questioning of conventional wisdom, the first issue which needs to be addressed is the validity of the study. Certainly, we do not want to 'learn' things which aren't true. We would not, for instance, want to go to Dresden, after the fire bombing, in an attempt to learn about fire's normal behavior. The first question that arose in the Oakland study was whether or not the black holes examined by the investigators represented the typical black hole likely to be encountered in an isolated setting.