Passive fire security design parts are accustomed to resist, retard and isolate flames along with the connected smoke and fumes: they do not in themselves extinguish flames hence they are classed as 'passive security'. Environmental Limits: Severe temperatures, large humidity, or corrosive environments could effect the lifestyle and overall performance https://www.thesafetycentre.co.uk/blog/ems-wireless-firecell-systems-from-the-safety-centre/