The Design Manual for Roads and Bridges (DMRB) and the Manual for Contract Works (MCHW) have recently been updated by Highways England (HE). For over ten years HA 104/09 (an ‘advice note’ within the DMRB) has been a key document for chamber tops and gully tops setting out procedures and denoting materials which Highway Authorities believe provide the best possible performance for installations in trunk roads and motorways.
In February 2020 the HA 104/09 advice note was replaced by CD 534, a new Technical Regulation posted and referenced on the European Commission Technical Regulation Information System (TRIS) website. CD 534 is now the document that contains HE’s requirements for road chamber top and gully top installations on motorway and all-purpose trunk roads. At the same time many requirements from the original HA 104/09 were moved to another HE specification document Series 500 of the Manual of Contract Documents for Highway Works(MCHW)Our handy #AskTheExpert videos will inform you on CD534 in bitesize chunks
Skid Resistance – PSRV >60
HA 104/09 had two required levels of polished skid resistance value (PSRV) depending on whether the site was ‘average/low risk’ or ‘high risk’. CD 534 now categorises high risk sites as ‘those where the predominant use is vehicular’ thereby requiring all Group 4 chamber tops to have a minimum PSRV of greater than 60 when measured by the pendulum test method in accordance with BS EN 13036-4 2011. Series 500 of the MCHW requires that manhole top samples are prepared by the accelerated polish test method described in BS 9124.
Neither standard defines where to set the datum for the test – the top surface of the chequer pattern or the lower surface of the chamber top cover.
What is the pendulum test?
Designed and used for floor and skid tests, the Pendulum Test, also known as the Sigler Pendulum Slip Test, is thought to have been developed by Percy Sigler at the National Bureau of Standards in the 1940s. Its main aim being to measure the slip resistance characteristics of all types of hard surfaces and flooring.
First trialled in government buildings, the Pendulum Slip Test was then adapted in the 1950s by the UK Transport Research Laboratory to test the skid resistance properties of a road and help avoid cars from skidding, especially around corners.
The pendulum test method today is commonly used for measurement of many types of surface friction, from indoor tiling and floor coverings to asphalt surfaces and concrete runways. The methodology for sample preparation and direction of test varies by application and substrate but the principle remains consistent across all surface types.