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Round D250

Terra Firma Round D-Class access covers offer strong, lightweight covers for minor in-road applications such as forecourts and inner roads with occasional traffic.

Terra Firma D-Class pit covers have been developed to give optimum performance and are significantly lighter than concrete and ductile options. Produced under carefully controlled manufacturing conditions our covers are precision made to ensure the highest quality fit between lid and frame. This means less wear and the elimination of a major cause of failure of ductile iron lids.

Our D-Class Round manhole covers are independently tested to meet all standards of AS3996.

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High structural performance

Structurally and fatigue tested. Meets AS3996 D210, AASHTO and European EN 124 C250 regulations.

Extended working life

Composite covers continue to perform well after 20 years in service. Will not break or spin out. The torsional resistant frames eliminate many of the usual causes of wear with traditional covers.

Permanent anti-slip

Exceeds 0.60 co-efficient of friction even when wet and will retain this anti-slip value throughout its working life.

Secure and lockable

Additional security may be included through a bolting system that automatically disengages when the cover is removed and reengages when replaced. High security key option is available.

Injury free removal

Single person removal and replacement without risk of injury. No need for any additional lifting equipment.

Reduced maintenance programmes

Longevity, ease of moving and superior performance reduces maintenance programs. Fitting a Terra Firma cover is the best ‘whole life’ choice.

Sealing (optional)

100% watertight/sand tight with an unique self cleaning edge seal.


Covers can be vented which helps prevent the build up of explosive gases. Ventilation holes conform to ADA regulations.

Transparent to radio waves

Negates the lifting of covers and helps promote better signals being transmitted.


Will not corrode when in contact with other materials. Unaffected by sand, salt and all chemicals met in road environments.

Electrically non-conductive

Will not conduct electricity, so stray voltage problems are negated.

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