JOINT BOX, CARRIAGEWAY & MANHOLE COVERS | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Covers for joint boxes and manholes were made in different materials. The footway covers were generally made of concrete, with steel or cast iron reinforcing around the edges and the carriageway covers made of cast iron. The covers fit in a frame and just lift off, as the weight keeps them in place. Carriageway covers in the early days were a cast lattice with wooden blocks forced in the spaces. Footway covers were fitted on Channels, Joint box whilst most covers for carriageways were fitted in a frame. Covers, Joint Box were later renamed as Covers, Footway. Covers, Driveway were introduced circa 1983. Certain covers can be supplied with ventilators or locks fitted. The type number, date and manufacturer can be identified as they covers will be marked. Most footway covers are labeled by a plate embedded in the concrete face, whilst others are marked underneath, on the casting. Click here for more information. All these covers are extremely heavy and after a period of time in situ they tend to jam in the frame due to grit or dirt ingress. Special keys are provided and each cover has a correct way to remove it. Due to back injuries sustained by staff working with these covers, the GPO spent a long time testing different mechanical lifting devices but most were not up to the job. The measurements below are for the cover only and do not include the frame. Click here for pictorial identification of covers Click here for pictorial identification of non-GPO/PO/BT covers List of Joint Boxes (as 1970) - A2G0101 Surface Joint Boxes - A2G0153 Joint Box No. 23 - A2G0161 Keys, Joint Box - Lifters for joint boxes Covers
Notes Cover, Unit Type and Cover, Unit Type (Light) are used on Frames & Covers, Unit Type and Frames & Covers, Unit Type (Light). These frames are modular and supplied in three types: A, B and C. The type A has a single cover, with two type B's being used to make a two cover installation and the type C being an intermediate frame that when used with two type B frames producing a three cover installation. The Light variant is not as deep as the standard type and are only used grass verges, crossovers, lay-bys and service roads. Originally called Frames and Covers, Unit Type 1, 2 3 and 4, they were renamed to Frames and Covers, Unit Type A, B and C. Click here for more information Covers, Manhole were superseded by Covers, Carriageway. Some covers were also produced with locks and ventilation holes.
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Last revised: March 13, 2026FM2 |