From price to cost

In the past, the view of access covers and gratings was quite simple - they were there to cover a hole.

This view has changed radically in recent years. Traffic intensity, speed and vehicle weight have risen, placing an increased emphasis on the durability and performance of access covers and gratings in the carriageway.

There is also a growing need for products to reflect the requirements of all stakeholders and allow for greater flexibility with regard to planned and reactive maintenance. Specifications have also evolved with many now incorporating requirements for products that include features that can offer safer, more secure and more efficient operation. More importantly, there is a growing understanding of the whole life costs associated with municipal castings and the need to reduce these, rather than merely focusing on the initial purchase cost of the product.

At the very least, a failed manhole cover generates significant disruption, inconvenience and cost which with correct product specification, selection, installation and maintenance can be avoided. The issue of whole life costs is in fact crucially important given the status of manhole covers as long-life assets, with a typical service life extending over several decades.

Many issues affect manhole cover performance. Climate change has resulted in more frequent heavy rain throughout the year, testing hydraulic capacities of gratings. There is also the issue of road safety and the risk of skids and slips for cyclists, motorcyclists and pedestrians caused by covers worn smooth by years of passing traffic. Municipal castings have also become targets for criminals in recent years - with covers removed and sold for scrap.

Given the length of service life, initial purchase cost is only a small percentage of the total cost of ownership. For example, an initial installation will cost around £800 to £1,000 including labour and traffic management, around 10 times greater than the cost of the access cover itself.

With incorrect product selection and poor installation and maintenance, it is no surprise that product durability and performance can be compromised, in turn leading to the additional costs associated with reinstatement or replacement If the bedding fails, reinstatement will cost £700 to £900 including traffic management - but premature manhole cover failure will entail a cost estimated at between £1,600 and £2,000 - many times the initial purchase cost saving.

There are human costs too; United Utilities estimates costs of £40,000 due to work stoppages cased by injuries to staff handling manhole covers. Yorkshire Water also has estimated an annual cost of £500,000 in replacing stolen covers.

However, even these costs appear modest in comparison to the likely costs of a legal case resulting from an accident involving a poorly maintained, worn manhole cover.

The impact on the social and public perception of the asset owner’s image is far harder to quantify, but even one instance can severely damage a company’s reputation and necessitate a lengthy exercise to win back public confidence.

Through collaboration, cooperation and innovation, the operational, regulatory and environmental needs of all stakeholders can be realised. It is this process which will promote the development and use of products incorporating features that will add to improvements in operator and public safety, asset security and durability.

Made from almost completely recycled material, the latest ductile iron castings are highly robust and durable, with in-service failures virtually unheard of. New products are designed to include as standard features to reduce the risk of injury, theft and premature failure.

The industry and Government has been lobbied for many years by cyclists and motorcyclists regularly having to traverse metal covers worn smooth by years of passing traffic, which became highly treacherous when wet. A recent significant innovation is the development of high friction antiskid access covers, a range of products combining the benefits of ductile iron with an aggregate surface to reduce the risk of skidding, particularly for twowheeled road users.

These products meet the requirements of the Highways Agency reference document HA 104/09, which for the first time refers specifically to the recommended skid resistance properties of chamber covers and gully tops.

This document is likely to be the first of many which enshrine in regulation the performance requirements of access covers, which in turn will drive further development in this area.

Paul Thompson is marketing manager - municipal castings at Saint-Gobain PAM UK.