We have been asked to inspect fire doors at a hotel and have found surface mounted intumescent strips on most of the doors.  We do not know the manufacturer.  Are these a suitable solution or should these be replaced with a "routed in door" system ? 

Please advise,  thanks

Check the product has evidence of fire performance and suitability for the doors in question  https://www.safelincs.co.uk/fire-door-seals-surface-mounted-intumescent-fire-and-smoke-seal-kit-product-1/