Surround to apparatus may be laid to a maximum thickness of 250 mm above the crown of the apparatus. The surround to apparatus must not intrude into the road structure. It may be necessary for the undertaker to lay apparatus deeper to avoid this.
Selecting materials for the surround to apparatus is the responsibility of the undertaker. All materials used for the surround to apparatus must comply with the following requirements:
Class E Unacceptable materials, as defined in A1.5, and materials that contain particles greater than 37.5 mm nominal size cannot be used as surround to the apparatus.
Hydraulically bound materials (HBMs) complying with A10.2 are permitted within the surround to apparatus as the entire layer or combined with any other permitted materials, in any proportion, within any reinstatement.
An alternative reinstatement material (ARM) may be used for the entire surround to apparatus or any part thereof, in accordance with A9.
Preformed modules or other protective measures may be placed within the surround to apparatus, according to the undertaker’s requirements.