It assumed a single relationship between wind speed and damage for every type of building. The Enhanced Fujita Scale (EF-Scale)

Well-built homes swept completely off foundations; structural steel deformed. How Forensic Meteorological Surveys Work

The EF-scale does not measure wind speed. It measures damage , which is a function of wind speed and exposure time, debris impact, and structural integrity. A tornado with 150 mph winds passing over an open field receives a lower rating than a 130 mph tornado hitting a well-constructed school.