Comparison of Actual Building Damage and Repair Costs from the Pepcon Explosion to Inhabited Building Distance Expectations

摘要

On 4 May 1988, an accidental fire and several explosions destroyed the Pacific Engineering Company (PEPCON) plant in Henderson, Nevada. The largest explosion, estimated as 500,000 pounds TNT equivalent weight, caused significant damage to the surrounding community, including portions of the Las Vegas metropolitan area. In 1990, property insurers joined in a lawsuit to recover their damage claim payments. With over 17,000 claims, the total alleged payment from the insurers totaled about $77 million. Through the legal discovery process, the defense team obtained copies of all damage claims; pertinent information was subsequently entered into a database. In 1992, Lloyd's of London, the basic defense underwriter, agreed to a $70 million settlement. Using the damage claim database, the authors were provided with a rare opportunity to evaluate actual damage costs resulting from an explosive detonation. The results are striking. According to DoD 6055.9-STD, the expected repair cost for an unstrengthened building, located at the Inhabited Building Distance (IBD) from an accidental detonation, is approximately 5 percent of the building's replacement cost. In the PEPCON accident, the nearest residences to the plant were located at distances much greater than the IBD. However, despite these greater distances, paid damage claims for these residences approached 20% of their replacement values. If the residences had been located at the IBD, they would have suffered significantly more damage, resulting in even higher claim costs. Clearly, DoD 6055.9-STD vastly underpredicts damage costs for these exposures. In this paper, we will first review current DoD safety regulations. Next, we will discuss the PEPCON accident and the calculation of blast overpressures resulting from the accident. We will then present the actual damage claims and will analyze their variation with overpressure.