After a 12 month-plus planning process, City Tower has installed condensing gas boilers and relined its chimneys to increase the efficiency of its heating system.
Those involved in the planning included GDM Building Services Design, Great Portland Estates, Associate Mechanical and Chimney Care.
The problem of lining the 80m high chimneys was solved by installing the specialised Class 1 Furanflex chimney lining.
Alan Rose, Chimney Care director, said: “The flues are very tall and if stainless steel liners could have been used the reduction in flue diameter would have caused serious problems.
“Various spray and drag coated sealants were considered, however these are not waterproof and could have caused problems with the condensates produced by the boilers.
“We researched the market and found a product widely used throughout Europe for the last 10 years which will mould to the shape of the existing chimney, is totally waterproof and carries a 25 year guarantee.
“These liners are also installed in one continuous length with no joints and therefore no chance of any movement or leakage.”
The installation was carried out over 10 days as the works to change the boiler plant continued, however the lining works were completed in 6 days.
David Fleming, Chimney Care technical engineer, carried out pressure tests on the new linings with a Wohler DP97 electronic pressure tester.
“I have tested all chimney lining systems with the electronic pressure tester and all systems are allowed a leakage rate depending on the surface area of the flue, this is the first time I have got a zero rate of leakage from the tester.”