Protecting buildings from blast effects

Published 3 April 2006

There are two ways to protect buildings from blast effects: Keep the source of the blast away from the building, or contain the explosion once the explosives made it into the building; here is a review of a blast-resistance trash can

There are two approaches to protect buildings from explosion. The most effective is to provide a barrier between the building and the source of the blast. A prime example for this approach are the physical barriers around the White House in Washington, D.C., preventing cars and trucks from getting too close to the building. The farther you push the source of the blast from the building, the more you minimize the effect of the blast on the structure. Often, this approach is not available. It may be possible to keep cars away from a building, but it is not possible to keep people away from public places such as railway stations. People may carry explosives in a belt around their waist or in a knapsack, or they may discreetly deposit explosives in trash cans on the platform. There is a need, therefore, for a blast mitigation solution inside buildings to tackle at least the bomb-in-a-trash-can event. These solutions should be light and flexible enough so they may be moved about while still robust enough to reduce the invasiveness of the blast wave. Note that this approach still leaves the structure vulnerable to damage that may lead to partial or complete collapse of the building, depending on the situation. The reason: The force of the blast has to be directed upward (to prevent the death or injury of people from a horizontal dispersion of the blast wave). Safety officials with New York Metropolitan Transportation Authority (MTA) gave this as a reason why there was little point in placing blast-resistant trash cans in most of New York underground stations: The stations’ architecture would make upward-directed blast waves as destructive as horizontal blast waves.

Dr. Glenn Miles of Lockheed Martin UK INSYS says that technologies developed to provide protection from blasts must perform the following functions: Blast mitigation from a single explosive hazard “in situ”; blast mitigation for an explosive-hazards storage area; protection of materials, structures, and people in areas close to the site of an explosive hazard or explosive-hazards storage area. “In order to fulfill these functions,” he continues, “any workable solution must have the following essential characteristics: flexibility and ease of use; low cost; high, scalable performance; low density; very low environmental impact; (and) longevity.”

There are several blast mitigation solutions out there, and the Journal of Mine Action has an evaluation by Miles of one of them — BlastWrap from Clearwater, Florida-based BlastGard International (OTCBBBLGA).