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DECONTAMINATION PUMPUP THE VOLUME


The eff ects of chemical and biological weapons (CBW) and toxic industrial materials (TIMs) on buildings and their occupants have received greater attention of late, particularly for those with responsibility for critical national infrastructure. Threats abound – from extremists, criminals and ‘lone wolves’, as well as accidents and natural disasters.


Decontamination action of LDV-X on indoor building surfaces.


T


he eff ects, however, are very much dependent on many factors: type and extent of incident, hazardous agents released, location of the


release, climatic factors, characteristics of the materials exposed to the agent, and – not least – airborne contamination related to air fi ltration and conditioning systems. The consequences of such an incident depend largely on the employment of eff ective decontamination methods and standards. Hydrogen peroxide in fi ne liquid aerosol and vaporized form is widely used for ‘large-volume’ biological decontamination in hospitals, largely because it is not an aggressive decontaminant. That said, it is not eff ective in decontaminating chemical agent vapour-contaminated surfaces. CRISTANINI’s LVD-X technology for


large volume decontamination (Figure 1) utilizes two separate liquid components: a water-based solution and activated hydrogen peroxide containing hydroxyl radicals (delivered by separate pipelines,


58 CBNW 2013/02


one red; one white). The radicals are generated by a heterogeneous catalyst combined with UV radiation. LVD-X generates and disseminates the fi ne aerosol of activation mixture and activated hydrogen peroxide solution. The components accelerate rapid dispersion throughout the contaminated area, decontaminating both the air and surfaces within the building.


Testing LVD-X Of course, building interiors contain large surfaces composed of a variety of complex, sensitive and porous materials, presented in whatever state that the release occurred. In order to determine the effi cacy of LVD-X, it was tested on panels composed of six diff erent materials contaminated with vaporized chemical agents GB, GD and HD. The six materials selected for the test were representative: plastic fl ooring, a painted gypsum board, sandstone, painted concrete and chemical agent-resistant coating. The testing objectives were to


determine absorptivity of selected indoor Experimental position of the LDV-X aggregate during the decontamination phase.


building surfaces exposed to vaporized CW agents, and to determine residual chemical agent within the substrate material structure aſt er application of LVD-X technology. CRISTANINI’s LVD-X decontaminant comprises a water based activator and a 30% hydrogen peroxide (H2O2) solution. For air and surface activation, which generates the reaction media, the water-based activator is used. The surface activation mixture should be applied either prior to the hydroxyl radicals deposition or simultaneously. The decontamination reaction is based on the chemical degradation of CB agents due to substantial oxidizing eff ects of


The hydroxyl radical oxidation rate is substantially higher than that of hydrogen peroxide:


Oxidant


Hydroxyl radical Hydrogen peroxide


Oxidation power (V) 2.80 1.17


Images: ©CRISTANINI


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