This chapter deals with materials used in safety and security engineering. The most commonly used materials in this field include shielding materials, materials for protective suits, electrically insulating materials and materials for fire protection. The first part of the chapter describes the properties of materials used in the above applications. The second part of the chapter focuses on characteristics of materials that accurately describe their fire risk. The fire risk of a material is quantified by its resistance to ignition (determined generally by critical heat flux and ignition temperature) and by the impact of the fire on the environment. The impact of fire is usually determined by the heat release rate, toxicity of combustion products (primarily determined by carbon monoxide yield and for materials that contain nitrogen, also through the hydrogen cyanide yield) and the decrease of visibility in the area (depending on the geometry of the area and the smoke production rate).
