Building regulations regarding replacing existing doors with fire doors

[JCarter5]

Having an extension on my house and a visit from the local building inspector has instructed me that all my doors (exisiting doors) will have to replaced with fire doors. Which act does this fall under to force me to change all of them?

[buildersmate]

I am very confident that this is exactly what you have done.
Under Part B, domestic dwellings where a habitable floor level is greater than 4.5m above the ground level requires a fire separation corridor.
Every time a householder puts in a third storey, the 4.5m will be breached. Your loft conversion company would not appear to be fit to be trading.

[clever trev]

Oh dear.......... Buildersmate you have come back from the
USA in a bad mood .( Not fit to be trading ) : >(