6
Connecting Flue Pipe
CONNECTING FLUE PIPE ROUTE
Single wall connecting flue pipes should only be used to connect appliances to a Chimney. They
should not pass through any roof space, partition, internal wall or floor, except to pass directly
into a chimney through a wall of the chimney.
Connecting flue pipes should be located as to avoid igniting combustible material.
On solid fuel appliances the maximum length of a connecting flue pipe is 2m. This distance is
reduced to 1.5m if any of the acceptable alternative methods of connection are adopted as per
BS EN15287-1. (See p.5 for full details.)
When a single wall connecting flue pipe is used to connect an appliance to a Twin Wall Insulated
System Chimney, the lower end of the insulated chimney section must extend a minimum of
425mm below the ceiling.
On appliances with a top outlet, it is recommended that a vertical run of at least 600mm should
be allowed immediately above the appliance prior to any change of direction.
On appliances with a rear outlet, it is recommended that there is maximum of 150mm in the
horizontal run however under certain conditions, as described in alternative methods in BS EN
15287-1, this may be increased to 450mm. (See p.5-6 for full details.)
Within a system (C Connecting Flue Pipe) there should be no more than 4 changes of
direction of maximum 45˚. 90˚ Factory made bends or tees within the system may be treated
as being equal to two 45˚ bends (as per Document J of the Building Regulations issued October
2010).
INSPECTION
Provision should be made for inspecting and cleaning the chimney system. This is important on
solid fuel applications.
An inspection pipe, inspection elbow or a 90° or 135° Tee with tee cap can form a suitable
inspection point (unless cleaning/inspection can be done through the appliance). To aid cleaning,
sufficient distance should be left between changes of direction to permit the safe passage
of cleaning brushes within the system. It is recommended that chimneys serving solid fuel
appliances be swept as frequently as necessary, but at least twice a year.
