- Upgrading the communal boiler plant serving three 10-storey housing blocks
- Need to minimise shutdown of existing system due to seasonal requirements
- Planning around Covid-19 restrictions made on-site work challenging
- Installing a sustainable heating system
Poplar Housing And Regeneration Community Association (HARCA) oversees provision of housing and resident support in their locality in the borough of Tower Hamlets in East London. The association needed to upgrade a boiler plant room, which provides three 10 storey-tower blocks with their heating and hot water, to a new and much-improved sustainable heating system.
Aston Group has been under contract to service and maintain all of Poplar HARCA’s boiler plant rooms for the past five years, and has recently signed a two-year extension due to the client’s confidence in the service and quality that Aston Group engineers have delivered. As such, when there was an urgent need for a replacement boiler plant at one of its facilities, Aston Group was immediately called into action.
Normally a boiler plant refurbishment would begin in the summer, when heating is rarely required. However, due to the age of the existing boilers, and the fact that one of the three boilers had already been decommissioned, the association felt it was not able to risk the remaining two boilers lasting through the winter.
The client also requested that the two remaining old boilers be retained as a backup should the new boilers ever fail, so a simple switch-over on the control panel and isolation valves have had to be factored into the planning of the works.
The challenge, therefore, was to keep the existing system running with minimum impact to the residents’ heating and hot water. The Aston project team strategically planned shutdowns and changeovers to keep these to an absolute minimum. By prefabricating the majority of the welding, a solution was devised that would only require two half-day shutdowns of the heating system.
Due to Covid-19, we had to produce a programme phasing the works to ensure we followed government guidelines around social distancing. Although the plant room area is quite spacious, we had to phase each work activity to ensure that social distancing and coronavirus-safe working procedures were maintained during the complete phased working arrangements.
For the first shutdown, we prefabricated 4” and 5” welded pipework and tees to allow us to switch off the existing heating and drain down the three tower blocks. Once drained down, this allowed us to cut into the existing 5” pipework and install our prefabricated tees.
New valves were fitted to the new tees and we could now start to refill and vent the three tower blocks and reintroduce the heating and hot water back in service. The disruption to the heating and hot water was around five hours, although electric heaters were available to any vulnerable residents and families.
The second shutdown required similarly fast and effective working. We prefabricated 4” welded pipework and tees to allow us to isolate the incoming gas supply. An Aston Group combustion engineer then attended the site to purge the existing gas main of gas; once clear, we cut our new tee into the existing one and welded it in place.
A new 4” gas valve was fitted and our combustion engineer reinstated the gas supply and purged the air from the gas, before carrying out a soundness test of the new gas pipework. Once the test was passed, the boilers were turned back on and we reinstated the heating and hot water. The disruption to the heating and hot water was around four hours, and once again electric heaters were available to residents.
We could now install new gas and heating pipes to and from our new boiler’s plate heat exchanger from our new installed shutdown valves. Once complete, our combustion engineer purged and soundness tested the new gas main to the boilers and commissioned the new boilers. The same was done with the new flow and return pipes from the shutdown valves: they were filled, tested, flushed clean and chemically dosed, ready to introduce the new system to the three tower blocks