Fire resistance of external walls adjacent to external escape routes

Fire resistance of external walls adjacent to external escape routes. Key requirements: Fire-resisting door (F.D.) shown in diagram. Window requires 30 minutes fire resistance. Within 1.8 m of the escape route from the bottom of the stair should be fire-resisting to a height of 1.1 m. The 1.8 m zone above the top landing of the stair may be reduced to 1.1 m provided that the top landing is not part of a basement stair. Maximum 6 m for stair to be unprotected from the weather. Stair door – no fire resistance required when fixed shut. Fire-resisting areas of wall shown in elevation and plan views with 1.8 m measurements from escape route and landing heights.