Hercules™ D400* manhole covers

Large chambers are commonly covered with steel access covers. But when the chamber is located in a Group 4 trafficked environment, steel rarely provides the solution. That’s where Hercules comes in, providing a durable, ductile iron solution to clear openings up to 1.2m x 1.2m.

Manufactured from high-strength ductile iron, Hercules D400 covers combine strength with precise engineering and a robust single-piece (unwelded) frame. The result is exceptional longevity, reduced maintenance and consistent performance, ensuring every installation meets the highest standards of safety, durability and cost efficiency.

Although covers above 1000 mm clear opening are outside the scope of BS EN 124:2015, Hercules has been engineered and tested to the same D400 performance criteria.

The covers feature a small, secure inspection window, allowing simple visual checks without the need to remove the full cover. This single-person inspection capability saves time, reduces handling risks and helps to keep maintenance efficient. For larger works, a threaded lifting eye can be attached to allow for safe, mechanical lifting, supporting compliance with manual handling best practice.

The anti-flex design of the Hercules D400 range ensures exceptional rigidity across the full span, preventing seating wear and eliminating excessive noise - a common cause of premature ironwork failure. Together, these features make Hercules covers a robust, reliable and low-maintenance choice, offering exceptional whole-life performance in the most demanding environments.