The need for a safe, durable, maintainable installed system for highways is behind the introduction of BS7903:2020 which provides guidance for the selection and installation of manhole tops and gully tops conforming to BS EN 124:2015. Barry Turner, Technical Manager at Wrekin Products, talks to BMJ and highlights the details that merchants need to aware of.

Why was there a need for BS7903:2020? With the publication of BS EN124:1994 “Gully Tops and Manhole Tops for Vehicle and Pedestrian Areas” and the simultaneous withdrawal of its UK-dedicated predecessor BS497, the UK market believed that there was a need to derive an advisory British-only standard which could adequately bridge the difference and perceived deficiencies between the new BS EN124 and old BS97.

The result was BS7903:1997 which became the advisory standard and included prescriptive information to guide UK manufacturers and specifiers alike. Coincident with the release of BS7903, came the publication of a co-sponsored Highways England and University of Nottingham research report, which presented a long-awaited scientific basis for more-effective chamber/gully top construction and design. The findings from this research project provided the foundation for derivation of subsequent Highways


Agency DMRB chamber top and gully top-related advice notes, such as HA104/02 & 09. With the release of HA104/02 (with 09 to follow) with its respected pedigree, conflicting BS7903:1997 advice became generally superfluous as the HA document addressed those topics in a more effective way, as well as including foundation advice. However, BS7903 still remained as the important reference document for chamber/gully top design features such as lifting key and keyways and frame flange web/gusset profiles, which BS EN124 contained no provision for. Since the release of the Highway Agency’s chamber top related documents, further WRc research crucially identified that foundation issues were the main cause of premature highway installation failure, and that these issues were strongly influenced by chamber/ gully top design features and the foundation materials that were selected to operate in conjunction with them.

Further service experience of improved product design, installation materials and practice has served to identify other previously unacknowledged factors involved in premature installation failure. Narrative on this has now been provided within the latest revision of BS7903:2020 and is just one of the reasons for its introduction.

What does

BS7903:2020 cover? BS7903:2020 also expands on

EN124 and highlights the need to consider pre-service loads (such as site construction traffic), frame designs that incorporate bedding-sympathetic features, installation materials suitability and compatibility, in-service dynamic forces imparted by traffic leading to potential seating wear, and limiting frame bearing pressure. This 2020 Standard also removes the discrepancy that existed between the 1997 version and Highways England’s Advice Note HA104/09 in relation to frame flange dimensions where the Highways Agency took account of published research in establishing effective flange widths.

BS7903:2020 is an important standard that assists in addressing a number of factors that previously led to installation failures which posed a safety risk as well as being a financial burden for the associated contractor and specifying authority. Despite the attention of most merchants and

their teams understandably being captured by COVID-19, it is also a good time to get up to speed on this essential standard that benefits not only those customers across the highways industry but road users too. BMJ August 2020

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