The UK CA Mark is coming


With the end of the Brexit transition period looming, Dennis Milligan of the British Flue and Chimney Manufacturer’s Association (BFCMA) looks at how the UK CA Mark will differ to its EU predecessor

Unlike many in the industry who have been set back by the coronavirus and having to furlong staff, legislators and those creating product standards have been busier than ever.

The end of the Brexit transition period on 31 December will see the introduction of the UK CA mark (UK Conformity Assessed). The UK CA mark will replace the CE mark for products being placed on the market in Great Britain.

There is of course one complication; in Northern Ireland and for products being sold into the European Union the CE mark will still be required. After all, it is Brexit.

But, for the most part, housebuilders and developers must be aware of the upcoming change and ensure all products used meet the new requirements.


2021 will be a transition year for the new arrangements, but the CE mark will no longer be valid in Great Britain from 1 January 2022. In 2021 a new product designed and manufactured in accordance with UK CA regulations should carry the UK CA mark.

The CE mark has become widely recognised as the mandatory approvals mark on flue and chimney products. The UKCA mark will take on this role now. Like the CE mark, the UK CA mark will be your guarantee that the product meets the latest product standards – to achieve the CA mark a product must be tested by a UK conformity assessment body to ensure that the product meets the latest standards and is fit for purpose.

The British Flue and Chimney Manufacturers (BFCMA) is currently working on the development of new product and installation standards that are due to be published in 2021.

Specifiers and installers in GB should start to look for the UK CA mark when they are considering the use of a product.

Matching the flue

The function of a chimney or flue is to discharge the products of combustion safely into the atmosphere. This, however, is not as straightforward as it may sound.

Most chimneys operate under negative pressure, relying on the laws of thermodynamics to transport the flues gases up the length of the chimney or flue to the atmosphere. This requires an unimpeded flow path to the top of the flue that maintains the temperature of the gases above the dew point.

Effective and continuous insulation is a key part in maintaining flue gas temperature, and chimney and flue standards are there to specify the components that should be used and how they should be used to achieve this primary function.

Chimneys and flues are required to discharge a variety of combustion gases, and different types of flue will be required to safely handle the different gases.

A key feature of the chimney and flue standards is a user-readable classification system that designates the features of the flue components. The features covered include temperature and pressure rating, fire, condensate and corrosion resistance, and distance to combustibles.

With stainless steel flues, a label showing the classification must be delivered with each flue component, so that the product’s specification can be easily verified. It is important, for example, to use a condensing flue with a condensing appliance, and the designation will help you do this.

Product testing

Product testing is the backbone of setting standards. Chimney and flue components are rigorously tested by approved test houses to prove that they can safely meet the required performance.

In addition to this, most chimney and flue companies use simulation software to confirm that a system chimney or flue will function as specified. If in doubt about the effectiveness of your chimney design, talk to the chimney or flue manufacturer about a chimney or flue simulation.

System chimneys

Product standards and CA marking will apply to both flue components and to system chimneys. It is worth pointing out that a CE or UK CA mark for a system chimney applies to the complete flue system, including additional components like rain caps.

The use of components that have not been tested with the system will invalidate the CE or CA mark and turn the system into a custom flue. As a custom flue the manufacturer’s system chimney guarantee is no longer valid in such a situation.

Design & installation guides

In addition to establishing standards, the BFCMA has also produced a number of design and installation guides covering wood burning and multi fuel stoves, biomass appliances, gas appliances and commercial flues – all of which can be downloaded from the BFCMA web site.

The design and installation of chimneys and flues in the residential sector are covered by Approved Document J, though the update of Document J is long overdue.

Dennis Milligan is president of the BFCMA