Ashmead keep a good range of gulley gratings & manhole covers made of cast iron and (mainly) ductile iron. These come in a variety of grades from A15 to D400. We keep various channel gratings up to E600. 
WHAT RATING DO I NEED? 
A15 1.5 Tonne test loading - suitable for pedestrian & cycles only 
A15 1.5 Tonne test loading - suitable for pedestrian & cycles only 
DUCTILE IRON 
Cast Iron (or grey iron) was used by the Victorians for 
many iconic engineering feats. However, one problem with grey iron has been its relatively brittle nature and lack of tensile strength. In recent years the introduction of magnesium into molton iron (making "Ductile Iron") has massively improved the strength and resilience of the material. This means that modern ductile gratings and covers can be lighter yet stronger 
than their cast iron equivalents.  
Manholes & gratings are classified according to 
BS EN 124 
C250 25 Tonne test loading - the standard for gratings installed up to 0.5M into the carriageway or up to 0.2m away from carriageway (distance measured from road face of kerb to grating location) 
D400 40 Tonne test load. Suitable for use in carriageways. 
E600 60 Tonne test load. Suitable for use in docks or airports where extreme conditions apply.