Newark boiler manufacturer Hoval complete work on London Tower Bridge

A boiler manufacturer Hoval has completed what could be a unique replacement ­— at Tower Bridge in London.

The legs that extend into the River Thames contain boilers in their bases and those boilers needed replacing.

Hoval, of Newark, was called in to work on the project.

The old boilers needed cutting up by hand and this was done in situ and the remnants hauled up the stairwells by hand.

The parts of the new boilers also needed to be carried down by hand before the new system could be constructed and welded together.

Hoval’s UK general manager, Ian Dagley said: “We are the only manufacturer in the UK that had the ability to build a bespoke system such as that.”

As well as being one of London’s most familiar historic landmarks, Tower Bridge is a popular venue for corporate and other events, with a number of unique spaces for hire.

The ageing boilers were struggling to meet space heating and domestic hot water requirements, so a decision was taken to upgrade them.

The work coincided with the conversion of a 9 metre-high exhibition space, with the addition of a mezzanine to create two new spaces.

The design was carried out by consulting engineers Brinson Staniland Partnership (BSP) and the new boilers, along with associated upgrade works, were installed by contractors T Brown Group.

Hoval engineers worked closely with both parties in meeting key challenges, ranging from providing design support to constructing the boilers in-situ because of access issues.

One of the early challenges faced by the design team was that, while regulations require condensing boilers for such an upgrade, the Grade I listing of the structure meant that Tower Bridge did not want plumes issuing from the flues on the side of the bridge base columns, ten metres above the water level.

Following lengthy discussions with the City of London authorities, special dispensation was given to use a bespoke, non-condensing boiler installation.

As a result, Hoval SR-plus 225 high efficiency, low NOx boilers were specified for the project.

“Not least of these challenges was access to the boiler houses through narrow walkways and corridors, steep stairwells, ship’s ladders and tight turnings,” said John Pearson, of T Brown.

“To overcome this, Hoval supplied the boilers in complete ‘knock-down’ (CKD) form, which were then assembled on site, fully welded ,hydraulically tested by Hoval’s engineers, and then casings, burners and controls were fitted.”

The original boilers were mounted on a platform suspended at 15m above the floor and this was extended by T Brown to accommodate the new boilers.

It was also important to avoid disruption to the venue, as well as to traffic in the area, with most deliveries being made during the night. Managing this situation required interaction with the Tower of London project team, the City of London, the Port of London Authority, Transport for London and two local authorities.

“Despite all the challenges, the project went very smoothly and the clients are delighted with the end result,” Mr Pearson said.