What Is A Boiler Flue & Why Is It Important?

Regulations around boiler flues are there to keep us safe from harmful gases produced by boilers. But what is a boiler flue?

What Is A Boiler Flue & Why Is It Important?

The combustion process in a household gas boiler produces harmful waste gases that must be removed safely from your home. The ‘flue’ is the pipe that’s fitted to the boiler to take these gases out of the boiler and into the atmosphere so they can disperse safely.

What does a boiler flue look like?

Modern boiler flues are typically short, horizontal pipes that jut out of the external wall. The size and shape prevents waste gases from re-entering the home.

Which gases do boiler flues emit?

• water vapour
• carbon dioxide (CO2)

If your boiler isn’t working properly, carbon monoxide may also be produced – it is a deadly gas.

What are the regulations around boiler flues?

Once, you could put a boiler almost anywhere, but today the regulations are very strict on its position.

As a guide, the flue needs to be at least:

• 1,200mm from an opening into the home, such as a door or window,
• 2,000mm below a Velux window
• 1m off ground level if it is facing a public space – for example a pavement
• 25mm below your guttering or any drain pipe or soil pipe
• 300mm above the ground, roof or balcony level below
• 300mm away from any opening window or air vent
• If it is situated on a ground floor wall, then a grill or metal box must cover the flue

Horizontal flues are the most commonly used type. Where the terminal is within two metres of an opening into a neighbour’s property, a vertical chimney system will be used.

L&W Heating and Plumbing

If you need to call on a Gas Safe registered plumber call L&W Heating and Plumbing experts for more information.

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