Passive fire protection design factors are utilized to resist, retard and isolate flames as well as affiliated smoke and fumes: they don't in on their own extinguish flames therefore They're classed as 'passive protection'. Smoke detectors are classified as the units and sensors that can understand potential fire threats. There https://www.thesafetycentre.co.uk/blog/ems-wireless-firecell-systems-from-the-safety-centre/