ABERDEEN PROVING GROUND, Md. – The development of an innovative physics-based model to support research and testing of decontamination technologies is the first-of-its-kind to come to fruition at the U.S. Army Edgewood Chemical Biological Center (ECBC).
CREATIVE (Contact hazard Residual hazard Efficacy Agent T&E Integrated Variable Environment) is a predictive decontamination system performance model (SPM) being developed to supplement and support existing decontamination evaluations in the laboratory, as well as during developmental and operational testing. The model is envisioned to be used to predict post-decontamination hazards before developmental and operational testing, or full scale testing of military equipment, takes place.
“We have successfully completed researching of a first generation model of CREATIVE which addresses contamination, decontamination and post-decontamination hazards of materials at the laboratory testing level,” said Brent Mantooth, Ph.D., a research scientist with ECBC’s decontamination sciences branch. “Right now, this innovative prediction model is focused on predicting what will happen at laboratory scale testing so that we can work towards predicting what would occur at full-scale testing.”
“With the model, we will eventually be able to take data and test results from laboratory testing and calculate post-decontamination hazards before the start of any full scale testing,” said Mantooth. “These calculations will produce all the information needed to determine if an equipment item undergoing full scale testing will be decontaminated to a level that is protective of the health and safety of the unprotected individual.”
According to Mantooth, the model will have clear advantages over the way decontamination technologies are researched and evaluated today. The model will shorten the development timeline for decontamination technology by helping to understand the performance of decontaminants. In addition, the model will help support full-scale testing during developmental and operational testing, and get a decontamination technology into the hands of the warfighter more quickly. As a result, testing conditions that are seen as too expensive or otherwise prohibitive can be reliably simulated.
Current decontamination technologies are tested in the lab using small samples of materials called panels that represent materials found on military equipment. Examples of these materials include glass, tire rubber, plastics and various paints such as Chemical Agent Resistant Coatings. These evaluations require a substantial amount of analysis including three types of tests in which multiple agents are tested on eight types of materials along with appropriate control groups. Technology evaluations could require up to 2,400 samples, and up to 7,200 if the recommendation to conduct the evaluation at three different temperatures is included.
“It is not practical to conduct testing at this scale.” Mantooth said. “This is where a physics-based model excels.
“There is an expressed need to develop a predictive model to support, supplement, and enhance our decontamination research and testing efforts. And we needed to bridge the gap with a predictive model that could be used between individual material testing in the laboratory and developmental and operational testing.”
The gap was bridged with the completion of multiple projects, including Development of the 2007 Chemical Decontaminant Source Document, the Small-Item Vapor Test Methods, the Vapor Composite System Calculation, and the Development of Complex Panel Methods.
The studies illustrated that in order to make a predictive model, mass transport first had to be considered. Mass transport is the movement of agent and a decontaminant into, within and out of a contaminated item. It is a complex, interacting system with many simultaneous dynamic processes, which include the agent, the material contaminated, how long the item was contaminated, migration of the agent into and out an item after absorption, the decontaminant used and elements of the surrounding environment, such as, air flow and temperature.
“By considering mass transport we can now recognize that decontamination is a complex, interactive system with many ongoing processes,” Mantooth said.
Mantooth explained a physics-based model enables researchers to understand the reasons for seeing the results observed in the laboratory. By simulating the physics and chemistry that occurs, there is a better understanding of what decontaminants are doing well and where improvement can be made.
To develop CREATIVE, the decontamination services branch modeling team used a mathematical technique called inverse analysis. This technique provided them the means in which to determine the physics-based parameters that could not be directly measured.
“The development of these techniques was vital to the development of the system performance model,” said Mantooth. “Now that we have the model parameters, we can simulate many of the what-if questions that were not practical to test at the full scale level, as well as identify which tests to conduct at that level.”
The model enables the simulation of many conditions with results that would indicate what vapor and contact hazards there may be to unprotected personnel in a variety of items. The results of these simulations will also indicate the need to consider many new aspects of when and how decontaminants are used and how they are to mitigate hazards.
Because of the complexity of conducting evaluations on decontamination technologies, Mantooth’s modeling team is currently working on a second generation model. This model will address evaluating multiple materials at the same time, along with other chemical agents and more complicated systems with the goal of being able to support and supplement evaluations at the full scale level in the future.
“The development of the CREATIVE model cannot be understated,” Mantooth said. “We will now be able to conduct future research, development and testing of decontamination technologies more quickly and at a reduced cost while getting it into the hands of the warfighter faster.”
For more information about ECBC, visit http://www.ecbc.army.mil/.
ECBC is the Army’s principal research and development center for chemical and biological defense technology, engineering and field operations. ECBC has achieved major technological advances for the warfighter and for our national defense, with a long and distinguished history of providing the Armed Forces with quality systems and outstanding customer service. ECBC is a U.S. Army Research, Development and Engineering Command laboratory located at the Edgewood Area of Aberdeen Proving Ground, Maryland. For more information about the Edgewood Chemical Biological Center, please visit our website at http://www.ecbc.army.mil or call (410) 436-7118.