Case Studies
Clark-Drain design and manufacture bespoke flush covers for Queen Mary University of London

When three underground chambers were required as part of a project to install a new emergency generator at a university campus in London's East End, three specially fabricated flush top covers were supplied to ensure access.

The project saw the installation of a 350kVa generator and steel mast supporting a 26m high exhaust flue, which serve as emergency back-up for the university. The design called for 150mm ducting for cables to run beneath a new tarmac surface, with three deep brickwork access chambers.

These chambers each needed bespoke 1m x 1.5m access covers.

London Surfacing Ltd, the main contractors, asked several suppliers including Clark-Drain to quote for the supply contract. Working from supplied specifications, Clark-Drain’s Specials Department created a proposal, with designs for the three covers.

London Surfacing’s Chris Stylianou says: “We were aware of Clark-Drain’s especially wide product portfolio and manufacturing capability, so we asked them what they could do for us. They won the contract not only on their ability to meet our specifications and quality standards, but also because they scored well on affordability.”

The covers were designed and fabricated in-house at Clark-Drain’s UK manufacturing facility. They were supplied to London Surfacing through George Lines, the Slough-based civils and landscape merchants.

Each of the chambers is located in an area with different maximum loads, so each cover was made to reflect this. In a pedestrian area, the cover is made to FACTA Class AAA standards. The other two meet Class B and D standards to cope with slow moving vehicular traffic. All three covers include sealing gaskets and locking systems to prevent unauthorised entry.

Chris Stylianou says: “The covers needed to be bigger than standard manhole covers so it called for tailor-made products. At Clark-Drain’s suggestion we opted for covers consisting of four parts in order to make removal easier when access to a chamber is required.”

The chequer plate covers were galvanised by Clark-Drain to BS EN ISO 1461, the key standard for galvanised coatings on iron and steel components. Application of this standard should ensure a 25-30 years lifespan with regular maintenance.

Along with specialist knowledge and manufacturing capability, Clark-Drain provides dedicated support services to projects like this one. Early involvement and site visits enable our team to advise on the best solution. Subsequent assistance including technical consultation and CAD engineering supports the quality and timely delivery of our customers’ projects.












Bespoke manufacture – unique covers CAD designed to the customer’s specifications for size, ergonomics, strength and durability.

FACTA standards – each cover was made to a different FACTA load bearing standard appropriate for the different locations.

Handling – a four-part design enables workers to remove the covers more easily than a traditional one-part manhole cover would facilitate

Long life – hot dip galvanising to BS EN ISO 1461 will ensure 25+ years of life.