Clear opening (gully, manhole tops, gratings, access covers)

• The diameter of the largest circle that can be in scribed in the clear area of the frame.

Error creating thumbnail: Unable to save thumbnail to destination

• Clear opening is defined as ‘Circular opening’ in AS 3996:2006 Access covers and grates and it is relevant for determining the test loads.

Error creating thumbnail: Unable to save thumbnail to destination

• Diameter of the largest circle that can be inscribed in the clear area of the frame of gullies (roof outlets & drainage outlets).

• Clear/Circular opening is a factor in determining the dimensions of test blocks, the test loads and the allowable set (deflection) for BS EN 1253-2:2003 Gullies for buildings.

Error creating thumbnail: Unable to save thumbnail to destination

References

1. SS 30:1999 Manhole tops and surface box tops.
2. AS 3996:2006 Access covers and grates
3. BS EN 1253-2:2003 Gullies for buildings – Part 2