A bomb suit, Explosive Ordnance Disposal (EOD) suit or a blast suit is a heavy suit of body armor designed to withstand the pressure generated by a bomb and any fragments the bomb may produce. It is usually worn by trained personnel attempting bomb disposal. In contrast to Personal armor, which usually focus on protecting the torso and head, a bomb suit must protect all parts of the body, since the dangers posed by a bomb's explosion affect the entire body.
Parts of the bomb suit overlap for maximum protection. The suit protects in several different ways. It deflects or stops projectiles that may come from an exploded device. It also stops or greatly decreases the pressure of the blast wave being transmitted to the person inside of the suit. Most bomb suits, such as the Advanced Bomb Suit, use layers of Kevlar, foam, and plastic to accomplish these functions.
In order to maximize protection, bomb suits come with a pair of interchangeable gloves and wrist guard attachments. This gives the wearer's hands mobility and protection needed for the task and avoid cross contamination of any evidence found (e.g., fingerprints).
EOD technicians wear bomb suits during reconnaissance, "render safe" or disruption procedures on potential or confirmed explosive threats. Such suits must provide a tremendous degree of protection from fragmentation, blast overpressure, thermal and tertiary effects should the threat device detonate. At the same time, the suit can significantly hinder their mobility or situational awareness.
As the United States saw its likely involvement in World War II, they requested help from the British to train a civilian EOD force that could defuse unexploded bombs in urban areas. The human cost of learning the variety of fuses and how to defeat them was lower for the U.S. due to this education. After it became clear that EOD tasks were best handled by the military, the U.S. tried several ways to organize EOD personnel that would allow for the need for both specialized training and diverse deployment. A short history of the beginnings of the U.S. EOD posted by the National EOD Association, accessed 26 July 2011. A short history of American EOD recounted by The Origins of U.S. Army Explosive Ordnance Disposal by CSM James H. Clifford (Ret.), accessed 26 July 2011.
In photos of early missions to defuse unexploded bombs,see, for example, A WWII bomb disposal case history, accessed 30 July 2011 the men are not wearing any protective gear. In fact, they are often shirtless to cope with the heat generated by the manual labor of digging around the devices before they could be defused. Basically, the individual defusing the bomb succeeded - or died.
The first EOD suits consisted of Kevlar type material and/or armor plates made of metal or fiber-reinforced plastic. Their purpose was to protect the wearer from penetrating injuries by fragments from an exploding device. In the mid-1990s, research showed that these materials alone were not effective against the blast wave itself, which can cause blast lung and other potentially deadly internal injuries. Modern EOD suits have layers of Kevlar, plating, and foam to provide protection from both fragments and the blast wave itself.
The threats posed by an Improvised Explosive Device, commonly known as an IED, can also include chemical or biological agents. This has led to significant advancements since 1999 in the design of bomb disposal suits and helmets. For example, a modern bomb suit may address both conventional blast threats and chemical/biological agents by incorporating a chemical protective undergarment and a helmet compatible with a self-contained breathing apparatus (SCBA).
In 2006, the U.S. National Institute of Justice supported a program to develop a national testing standard for EOD suits so that the protection afforded by a given suit can be described in a standard way.Waclawik, S. Explosive Ordnance Disposal Personal Protective Equipment (EOD PPE) Standard. Presentation by the Ballistic Technology Team, Natick Soldier Center, Natick, Massachusetts, USA. read online The goal was to have a means to compare the performance of different designs with each other and with expected threats, similar to the NIJ standards that are widely used to test and compare body armor or materials used to stop ballistic threats.
Developers must consider more than just protection, since a person must work on a stressful task that also requires fine motor skills while wearing a bomb suit. Other factors that must be considered include
Until the mid-1990s, EOD suits consisted of Kevlar and/or armor plates to stop projectiles. However, the suits did not offer much protection against the blast wave itself. The most recognized injury due to the blast wave is called “blast lung.” The lungs (and other internal organs) can be injured by the blast wave and bleed, even when there is no penetrating injury; such internal injuries can be fatal. In the mid-1990s, research conducted in the UK showed that textile and rigid plate armor by themselves do not protect the lungs from blast injury. It was found that a layer with high acoustic impedance with a backing of a softer, low-acoustic impedance layer (such as low density foam) would protect from blast injury. However, it was also shown that it is important to understand the frequency content of the applied blast wave and to experimentally test the way materials are put together to make sure they are effective.
The materials needed to make bomb suits protective do not release body heat generated by the wearer. The result can be heat stress, which can lead to illness and disorientation, reducing the wearer's ability to accomplish the task.Stewart, Ian B.; Rojek, Amanda M.; Hunt, Andrew P. Heat Strain During Explosive Ordnance Disposal. Military Medicine, Volume 176, Number 8, August 2011, pp. 959-963. The most recent models of bomb suits include battery-operated cooling systems to prevent heat stress. One manufacturer's study claims that the internal cooling systems on bomb suits helped the wearer stay at workable temperatures for up to an hour, even in a hot environment.Thake, C.D., et al., A thermal physiological comparison between two Explosives Ordnance Disposal (EOD) suits during work related activities in moderate and hot conditions. read online
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