New fire stopping details

Currently on a project where new fire stopping details have been issued, showing either side of the pentration being thermally wrapped 500mm.

When calculating cable sizes would Ci be used as this would be at 0.5 and worse case.

  • This depends rather on what the cables are wrapped with and its thermal properties - 500mm is a long distance compared to the situation for which the existing cable rating tables were derived. If a cable is sufficiently well insulated then perhaps  even the de-rating factor of 0,5 my not be enough. It may be that the routing method needs to be changed, or the actual material tested to see what the temperature rise actually is.
    Mike