Building defects database - Flue: fanned balanced flue

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Figure 4.33 This is a fanned balanced flue from a gas boiler. Because it is below 2 metres from the ground level, it has been fitted with a protective cage. Using Part J of the Building Regulations as a guide, a typical fanned flue has to be a minimum of 300mm below a window opening, 300mm from the door and 150mm from the RWP. It is beyond our role to either know or measure these distances but a general knowledge of typical distances will help you form a broad opinion of suitability.
Figure 4.33 The pipe to the right is a soil and vent pipe from the bathroom in this 1980s terraced house but the pipe to the left comes from the gas boiler. Although it looks like an open flue it is a fanned balanced flue from a modern condensing appliance that will have different distances to that of an open flue.