Measures for Progress: A History of the National Bureau of Standards

Fire-severity tests of buildings, deliberately made on abandoned structures in downtown Washington the 1920's. In the picture at left, the walls of a
non-fire-resistive building began to bulge after 40 minutes. In the picture at right, a five-story and adjacent two-story structure, near the old Post
Office Buildings, that were soon to be razed were loaded with typical office furniture, along with 30 types of office safes. Besides determining
the progressive temperatures of the fire, observations were made on the destruction of the buildings and the effects of the fire on the structure
and contents of the safes. The fire threatened to get out of control and local fire officials never again permitted such Bureau tests in a congested
area.