A guide to Standards for Highways CD 534 V0.2.0

Standards for Highways has updated a significant set of its requirements for manhole covers and gully grates installed on the road network, for which it is responsible. The document in question is CD 534, which was first released in February 2020 and has now been updated to version 0.2.0 as of September 2025.

CD 534 initially replaced HA 104/09 and forms part of the Standards for Highways Design Manual for Roads and Bridges (DMRB). CD 534 equally applies to the network managed by Transport for Scotland.

While this revision refines structure and guidance, particularly around chamber positioning and the removal of units from pathway locations, its core principles on ironwork design, performance and compliance remain consistent with previous editions.

Take a look at the full standard

CD 534 recognises that load transfer from the frame to the underlying bedding material is an important factor in determining the lifetime of an installation. To ensure that an adequate area is provided to spread the load, without overstressing the bedding material, CD 534 sets a minimum frame flange area for all 600x600mm and 675x675mm manhole cover frames. The required minimum frame flange areas are shown in the table below:

As with HA 104/09, these minimum flange areas equate to the ‘nominal bearing pressure’ of 2.1N/mm². This was omitted from the first version of CD 534. Nominal bearing pressure is calculated by dividing the 400kN (D400) or 600kN (E600) test load by the flange area.

All Wrekin Highway and Unite ranges comply with this requirement.

To ensure frames are stiff enough to resist the loads involved, in this latest version of CD 534, a lower limit of frame mass has been specified for all 600x600mm and 675x675mm manhole cover frames.

All Wrekin Highway and Unite frames satisfy this requirement.

A frame depth of 150mm is now required on all installations on motorways and all-purpose trunk roads.

All Wrekin Highway and Unite ranges are available with 150mm frame depth options.

CD 534 stipulates only one type of test for covers with a raised chequer. Previously it could be satisfied with the conventional pendulum test, which measures the resistance caused to a swinging ‘shoe’ by the cover surface, or the more recent WRc test, which measures a small tyre’s resistance to sideways slip caused by the cover surface.

Since CD 534 v0.1.0 it has been mandatory to demonstrate compliance with the WRc test, and this remains the same in v0.2.0. All manhole covers with the Wrekin triangular or Unite chequer satisfy these requirements of CD 534.

All Wrekin Highway and Unite ranges comply with the requirement.

CD 534 v0.2.0 introduces a standardised specification for keyways and lifting keys used with chamber tops and kerb-type gully tops.

This change replaces the previously inconsistent or manufacturer-specific designs that existed across the industry.

General Requirement

Keyways and keys for chamber tops and kerb type gully tops must conform to the dimensions shown within the standard. The aim is to ensure:

• Compatibility and safety when lifting or maintaining covers.
• Consistency between manufacturers.
• Reduced risk of damage from incorrect or non-standard lifting tools.

All Wrekin Highway and Unite ranges meet these requirements.

CD 534 v0.2.0 makes it explicitly clear that chamber tops are not permitted anywhere within the carriageway on roads covered by the standard. This includes motorways and all-purpose trunk roads, collectively referred to as CD 534 applicable roads.