vi) Cables may be stacked 2 high (max) on ladder and tray installations. Spare capacity should be provided on all installations (1 additional cable or 20% of total number, whichever is greater).
vii) Tray and ladder routes shall avoid obstructions, hot surfaces, vibrations and areas of high ambient temperature. Minimum clearance from hot surface (above 65oC) shall be 300mm. The route shall not run beneath parallel runs of process piping and shall not block walkways or access to equipment.
viii) Routes, which cross walkways, shall provide a minimum headroom of 2 metres. Routes that cross roads or areas requiring vehicular access shall provide a minimum headroom of
5.5 metres.