Impervious 04 : incapable of being penetrated. Secondary containment structures must be sufficiently impervious to the types of products stored within the area of containment
HM Government, Strategic National Guidance, The Decontamination of Buildings, Infrastructure and Open Environment Exposed to Chemical, Biological, Radiological or Nuclear Materials, Appendix B: Glossary, Produced by the Food and Environment Research Agency on behalf of: The Cabinet Office, Department for Communities and Local Government, Department for Environment, Food and Rural Affairs, The Home Office, The Northern Ireland Executive, The Scottish Government and The Welsh Assembly Government, London, UK 2011. https://update.cabinetoffice.gov.uk/sites/default/ files/resources/CBRN-StrategicNationalGuidance.pdf , (Decont of build, infrastructure & open Env expos to CBRNE mtrls - Brit) {588}
