MANHOLE RINGS & COVER SLABS - SIZES, WEIGHTS & ACCESSORIES Sizes, Weights & Accessories  Size in relation to sewer pipe size  Manhole types  How to specify manhole rings Summary Tracey manhole rings and heavy duty cover slabs are manufactured in accordance with BS.5911 PT200. They are available ex stock in a wide range of standard diameters and depths. All units are made in modern factory controlled conditions and carry the British Standard Kitemark logo. Tracey Manhole Rings Details of Cover Slabs to suit the Manhole Rings Steps to BS 1247 Ductile Iron Covers to BS EN 124 18 x 18mm Conseal Jointing Strip in 4.5m rolls supplied to fit between and seal each manhole ring.