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Pumice is proving to be an effective and economical blast mitigator for use in munition transportation containers and blast shelter applications.
blast mitigation
Lightweight and economical, Hess pumice is an ideal absorptive material for a variety of blast mitigation applications.
Blast Mitigation Defined
Blast mitigation is the process of making an explosive blast less severe and has everything to do with the selection of materials based on resistantance, attenuation, and absorption of the blast effect.
The various materials used for blast mitigation (including pumice) each have properties that are unique to certain blast situations.
Blast Attenuating Materials
The natural micro structure of pumice stone—a frothy web of air-filled vesicles—classifies it as a cellular solid. (Cellular solids include metallic, ceramic, honeycombs, polymer foams, and micro-truss structures). Pumice exhibits a microstructure very similar to expensive advanced ceramic foams.
When used for purposes of blast mitigation, cellular solids, like pumice, collapse at a cellular level beneath the force of the blast, absorbing much of the blast energy and effectively containing the damage. The TABREShield™, by the UK's Aigis, is a good example of the use of a pumice aggregate in the blast process...
"[The] system works through attenuating the peak over pressure from a blast. Through the systematic disintegration of the material, first with gross cracking, then with the breaking of the inter-particulate bonds and finally with the pulverising of the aggregate particles, blast energy is absorbed. Attenuating and absorbing the energy over the spectrum of the blast event substantially reduce incident and reflected pressures."
Pumice as a Blast Mitigator
Lightweight, abundant and easily processed to any spec, pumice is proving to be effective and economical, as the manufacturing process simply involves combining pumice aggregate with an epoxy binder and sandwiching it between rigid panels or flexible sheets. The loose, granular nature of pumice makes it ideal for use in flexible-sheet blast mitigating assemblies.
When used for storing and transporting energetic materials, like munitions, pumice has proven effective for preventing sympathetic detonations, inhibiting fragment impact action, and substantially increases the capacity of the confinement vessel. An example of this type of munitions container is the SLAM-ER CNU-595 (container for SD rockets) consisting of an aluminum shell filled with 4-inches of pumice.
