Many BFCMA members make industrial chimney products for a range of commercial applications and all can offer useful, practical design advice, says Robert Burke.
A great deal of time, effort and money has been spent by British Flue and Chimney Manufacturers Association (BFCMA) members over recent years working with the Government to ensure regulations and standards are written in a way that makes them both safe and practical.

Everyone knows that a standard that is too onerous or ambiguous in its wording won't be applied correctly. This, in turn, can lead to safety and performance issues.
We are fortunate that active members are able to make frequent journeys to London and across Europe in order to make chimney products and installations safer.

However, all the good work being done by BFCMA members needs to be communicated. Installers and engineers need to know what changes to regulations are coming and that is why this usually takes the precedence in magazine article. Unfortunately, this is inevitably at the expense of letting people know what a tremendous and comprehensive range of products and services our members can offer.

Excellent customer service

Most people are aware of the range of domestic chimney products made and supplied by BFCMA manufacturers. Typically, clay, concrete and pumice chimneys are supplied into new build housing. These chimneys are both affordable as part of the structure of the building and have a life expectancy commensurate with the expected life of the house. Twin-wall metal system chimneys are the obvious choice when retrofitting an appliance into a house that doesn't have a suitable chimney. Flexible metal linings come into their own in the repair of old leaky brick chimneys.

What's not obvious to most people is the fact that many BFCMA member companies also make a range of industrial chimneys to suit most industrial and commercial applications and these are backed up by excellent customer services offering both design advice and installation.

Industrial chimneys come in many variations to suit the variety of applications found in commercial premises (such as office blocks, shops and even community heating schemes) and industrial chimneys used with process plant.

The most obvious difference between industrial chimneys is their size. Where domestic flues and chimneys tend to between 125mm and 300mm, industrial prefabricated chimney sections are available in diameters up to 1,200mm.

However, it is not only the size that is different. In most cases, domestic chimneys operate under negative pressure, relying on the buoyancy of the hot flue gases to safely evacuate the products of combustion to the outside atmosphere whereas industrial chimneys usually operate with an exhaust fan that subjects the flue to positive pressure. Most industrial chimneys have been designed and tested to operate safely under these conditions. In the most extreme pressure class, chimneys are available for use with the most demanding generator exhausts.

Besides having to withstand the rigours of high pressure, there is also a range of chimneys that operates under wet conditions. In these circumstances, the chimney must be able to withstand the corrosive condensates generated by large industrial condensing boilers. This condensate must then be able to be safely drained away and be neutralised.

While the prefabricated chimney sections of industrial chimneys are able to stand many tens of metres tall, they are not self-supporting. To combat this, a range of support masts is available which takes the wind load and offer support to the system chimney sections.

In some cases, an external steel chimney housing can be provided which, in turn, houses a number of chimneys, with internal ladders and platforms.

Design is complicated

It is clear from the varied range of products available that the selection and design of the correct chimney is a complicated matter. Fortunately, this process is made a lot simpler for the designer or specifier by using the services offered by many BFCMA members.

From an initial site survey, the experts in many chimney manufacturing companies can give advice on the optimum system that will result in both cost and performance benefits. They will be able to determine the best chimney size for the application.
Terminal sighting advice to comply with the Clean Air Act is also available, including dispersion modelling of the exhaust gas plume. Once the optimum design has been agreed, layout drawings can be provided and on-site installation arranged.

Choosing the correct chimney is an important part of any heating plant installation. It makes sense to get this correct at the design stage and no one is better placed to help with this than BFCMA members.

After all, they are the ones who have dedicated the time and resources to ensure the standards and regulations in the UK provide for safe and reliable chimneys.

• Robert Burke is president of BFCMA and deputy CEO of ICOM Energy