Fire Alarm I am fitting a fire alarm what is the allowed distance from a light to a heat sensor on the ceiling

The segregation requirements relating to a fire alarm system in a dwelling are dependent on the grade of the fire detection and alarm system used (see BS 5839). Fire detection and alarm systems are graded either A, B, C, D, E, or F. Grade ‘A’ and grade ‘B’ fire detection and alarm systems are more sophisticated than those graded C, D, E, and F, which comprise one or a number of individual smoke alarms, fire detectors and fire alarm sounders according to system grade. Grade ‘A’ and grade ‘B’ fire detection and alarm systems are integrated systems generally incorporating a control and indication panel or panels, and are the only systems that require segregation additional to the segregation required by BS 7671 Before installing a fire alarm system in a dwelling it is therefore necessary to determine the grade of system to be installed. If this information is not readily available it should be obtained from the fire alarm system designer. As a general rule and in order to comply with BS5839, the heat detector must be positioned at a point on teh ceiling such that it is within 5.3m of every wall, including diagonal measurements to the corners of the room.

Minimum 300mm from a light and 500mm from a wall