Passive fire defense development elements are used to resist, retard and isolate flames and also the associated smoke and fumes: they don't in them selves extinguish flames as a result These are classed as 'passive defense'. – For advanced web pages with various properties such as schools or colleges – https://www.thesafetycentre.co.uk/blog/ems-wireless-firecell-systems-from-the-safety-centre/