Intergas solution to non-compliant plastic flues

On 14 June 2017, just before 1.00am, a fire broke out in the 24-storey Grenfell Tower block of flats in North Kensington and there can be few who are unaware of its tragic outcome. In May 2018,  after an investigation into causes of the fire’s rapid spread, Dame Judith Hackitt’s Independent Review of Building Regulations and Fire Safety: Final Report was presented to Parliament. In the wake of this report the Ministry of Housing, Communities and Local Government (MHCLG) introduced the Building Regulations (Amendment) 2018, which effectively bans the use of combustible materials on the external walls of new buildings over 18 metres high.

Where we might have thought ‘external wall’ meant cladding, balconies and decking, we’ve had clarification that an ‘external wall’ includes ‘anything located within any space forming part of the wall’. In a nutshell, this Amendment effectively renders all boiler installations in high-rise buildings non-compliant as most gas boiler flues are made of polypropylene plastic (PPE), which is classed as a combustible material. The MHCLG is currently conducting a review into whether PPE flues should be exempt, but a decision could be months away meanwhile, high-rise homes require boilers which are compliant. The Heating and Hotwater Industry Council (HHIC) estimates that of the 1.7m gas boilers sold in the UK each year, around 20,000 will be installed in high-rise buildings.

Currently the only condensing boiler in the UK with a metal flue system, and therefore complies with the Amendment, is the Rapid, a boiler which has been part of the Intergas range for 23 years. The material compounds of galvanised powder coated steel and high grade aluminium, used in the manufacture of the Rapid flue, have been tested to prEN 1856-1 and are therefore classified as A1 in accordance with EN 13501-1 A1.

Speaking about plastic flue non-compliance, John Lawton, Technical Product Manager, Intergas Boilers, said: “We have been in discussion with the HHIC and the Building Research Establishment over the past few months to try to establish how we can best support the industry, installers and residents. If we are to uphold the findings in Dame Judith Hackitt’s Final Report, then we may have to face a future where plastic flues must be replaced by metal in all high rise buildings.”

The Intergas Rapid condensing combi is available in two outputs: 25kW and 32kW. Like all Intergas boilers it comes with our unique two-in-one heat exchanger, has only 12 components, which includes four moving parts, features a built-in expansion vessel, combined pressure relief valve and condensate trap and delivers flow rates of up to 13.2 litres a minute. And the Rapid is more than just a combi; by changing the parameter settings, it can easily be converted to a system boiler, open vent/heat only boiler, open vent combi or a multipoint water heater.

To satisfy the demand for a boiler and flue system suitable for contract installations in buildings over 18m high, we have now made the Rapid High Rise boiler range available as a pack. For further information about the Rapid High Rise boiler pack, please contact Manny Puletti, Sales Director at For all technical enquiries, please contact the  technical helpdesk team on 01527 888000 or email