Valiant House – a follow up
Using modern methods of construction and prefabrication enabled a housing association to refurbish one of its high-rise residential tower blocks
Charlton Triangle Homes (CTH), part of the Peabody Group, provides affordable, high quality homes to thousands of people. Maintaining the properties to the required standards is the responsibility of Peabody’s Electrical and Mechanical Services division. So, when the Charlton Board reported some deterioration in the performance of the building services at Valiant House, a 17-storey residential block containing 93 flats in Charlton, South East London, the team was called in immediately to carry out a rigorous survey.
The findings were that, despite previous improvement work within the rooftop plant room, the non-condensing boilers at the heart of the central heating plant were beginning to show signs of inefficient and uneconomical operation.
A further issue was the gas main. It had reached the end of its 50-year-old life and, with thinning pipe walls, needed replacing to comply with new regulations and HSE requirements. SGN, which supplies the gas to Valiant House, was also preparing to replace its gas pipes through the building.
For CTH and Peabody, the challenge was to achieve a long-term heating solution that would reduce both utility bills and the carbon footprint of the building while ensuring uninterrupted continued use of the building. Working with an external consultant, they reviewed the findings and evaluated a number of proposals.
The options
Ground source heat pumps (GSHP) – this low carbon option, while in line with CTH and Peabody’s wider environmental commitments for a reduced carbon footprint, had to be ruled out as it wasn’t deemed technically viable at the time.
Replacing the gas main and pipe risers to the building – another option that had to be rejected as it would have required removing concrete through floors to access the existing pipework, creating extra work to protect the building structure. Running a gas main up the side of the building to the rooftop plantroom would have brought additional scaffolding costs due to the size and weight of the pipes.
Relocating the original rooftop plantroom – the Board’s preferred option involved installing new high efficiency condensing boilers in a newly created centralised ground floor plantroom at the rear of the building. The new boilers supply new Heat Interface Units (HIU), unvented indirect cylinders with electric back up, and individual heat meters in each property. This proposal included the replacement of cold-water tanks with new cost-effective sprinkler tanks and fire precaution upgrades.
On this occasion, the Charlton Board found this to be the most robust option. Relocating the plant room to the ground floor removed the need to run extensive pipework up the building, thereby minimising works on the floors and avoiding disruption to the residents.
Replacing the ageing, inefficient boilers with new, more energy-efficient condensing boilers – with a life expectancy of 20 years plus and capable of meeting the demand of the building – met the requirement for long-term improved reliability and efficiency and an immediate reduction in carbon emissions. CTH and Peabody were also keen to explore the possibility of upgrading to hydrogen boilers in the future to provide a non-disruptive route to low carbon heating.
Once this approach had been agreed, Milverdene was appointed the project contractor while Baxi Heating was asked to supply a heating and hot water solution.
Prefabricated, pre-assembled solutions
Six Remeha Quinta Ace 115 boilers were recommended to meet the specification within the design parameters. The boilers were supplied with pipework, pumps and plate heat exchangers on an off-site prefabricated skid for fast and easy installation.
To enable rapid installation of the heating and hot water element in the individual properties, Packaged Plant Solutions provided the new Megaflo Eco 125 litre cylinders pre-assembled with the associated pipework. Supplying the unit, together with controls and a heat meter, the prep-plumbed cylinders and first fix rails meant that Milverdene would be able to slide the equipment easily into the existing utility cupboard spaces.
“The major advantage for us was the time saved on site,” explained Ian. “The works began at the start of 2020, so with COVID-19 restrictions in place just a few months later, we were running a little behind.
“However, thanks to the prefabricated solution provided, Milverdene were able to complete the changeover in just one day and refurbish five properties a day, putting us firmly back on schedule. We also didn’t have to worry about multiple deliveries or materials being left on site as the solutions arrived pre-assembled and ready for installation just when needed.”
Once the electrics, radiator sizing and valves had been checked and a new sprinkler pipe and sprinkler heads fitted, the project was completed and delivered on time and budget.
“Charlton Board and the residents are delighted – the new plant room looks great and it all works brilliantly,” said Ian. “It’s a fantastic result and we are anticipating considerable energy and carbon savings from our new energy-efficient services.”
Tom Murray is Specification Director at Baxi Heating
