9. Horizontal openings: Excavations, wells or basins presenting a falling hazard shall be solidly covered or protected with guardrails on all exposed sides.
The same applies to vats, tanks, reservoirs, basins and other containers used for the storing or mixing of substances that are open and whose opening is less than 750 mm above floor level or above a working platform.
This section does not apply to basins used for recreational or fish-breeding purposes.