(6)Isolation valves shall be installed at each of the following locations:-(a)on the suction end and the discharge end of the pump station in a manner that permits isolation of the pump station equipment in the event of an emergency;(b)on each line entering or leaving the installation in a manner that permits isolation of the installation from other facilities;(c)on each main line at locations along the pipeline system that will minimise damage from accidental product discharge, as appropriate for the terrain in open country or for the location near cities or other populated areas;(d)on each lateral take off from a trunk line in a manner that permits shutting off the lateral without interrupting the flow in the trunk line;(e)on each side of a water crossing that is more than 30 m wide from high-water mark to high-water mark;(f)on each side of a reservoir holding water for human consumption.
