The origin of the fire insurance grading system dates back more than 100 years to a time when major fires destroyed large portions of cities in Canada and the United States. Historical fires such as the Great Fire of Portland (1866), Great Chicago Fire (1871), Great Toronto Fire (1904) and the 1906 San Francisco Earthquake and subsequent fire focused attention on the vulnerability of cities to the threat of conflagrations. During this era, water supplies, fire departments and fire codes were in their infancy and were simply not sufficient to prevent or control large, devastating fires. more... See more text