This design note adopts a 300 mm horizontal air-gap separation between primary and secondary life-safety trays on roofs, based on these regulatory requirements and established UK guidance. BS 7671:2018 +A2:2022 states: “Circuits of safety services shall be independent of other. UK electrical and fire safety standards do not prescribe a fixed minimum separation distance for roof-mounted life-safety cable trays. However, BS 7671, BS 8519, and BS 5839 collectively establish that life-safety circuits must be installed on dedicated containment and be either separated by. Although BS 7671 touches on the subject of cable supports, it does not detail specifically what these support distances should be. Clause 522-08-04 Where conductors or cables are not supported. When installing two cable trays in parallel at the same height, the distance between them should be no less than 0. This spacing is crucial for adequate maintenance access, ease of inspection, and ensuring proper airflow for effective heat dissipation., pipes, cables, ducts) and/or between services and the edge of an aperture/fire seal. It's not a generic rule of thumb; it's the dimension proven in a test or technical assessment for a. 521. NOTE 3: This regulation precludes, for example, the use of non-metallic cable clips or cable ties as. This publication is intended as a practical guide for the proper and safe* installation of cable ladder systems, cable tray systems, channel support systems and associated supports.
