Three different explosives tests were conducted on the Eglin Test
Structure. The first test used 704 pounds of Tritonal, which is
equivalent to 830 pounds of TNT, or roughly 2,200 pounds of a
properly prepared ammonium nitrate / fuel oil (ANFO) mixture.
The Tritonal was contained in a light aluminum case and was placed outside the
structure at ground level 25 feet from the vertical surface of the
40-foot side wall. This test most closely parallels the truck bomb at
the Murrah Building and provides important parametric data for
assessing blast-wave damage at the Oklahoma City site. Besides being
external to the ETS, the aluminum casing provided a container similar
to the light shell of the Ryder truck. Like the truck bomb, the
Tritonal test attempted to effect damage to the concrete structure
with an air-couple blast wave without the help of heavy shrapnel.
By contrast, the second and third tests used steel-cased warheads
detonated inside the ETS. The second test used a standard Mk-82
warhead (equivalent to 180 pounds of TNT) placed within the first
floor corner room approximately four feet from the exterior wall. The
third test involved a 250-pound penetrating warhead (having an
equivalent explosive weight of 35 pounds TNT) which was placed in the
corner of a second floor room approximately two and a half feet from
the adjoining walls. As the photographs from Wright Laboratory
graphically show, these two explosive devices, although much smaller
than the Tritonal device, effected far greater damage to the ETS. This
disproportionate destruction was largely a function of three critical
factors: distance, mechanical coupling of the blast wave, mechanical
coupling via shrapnel, and contained pressure (due to being confined
within the structure).