Flue; Builders Opening - Baxi Bermuda Inset 2 Boiler 50/4 Installation And Servicing Manual

4.0 Site Requirements - Page 10

4.5 Flue

1. The flue installation must conform to BS 5440 Pt 1. The
flue must have a minimum vertical height of 3m (10ft) and
2
have a minimum internal cross section area of 12,700 mm
2
(20in ), this is satisfied by a flue of 125mm (5in) internal
diameter.
A suitable terminal is required for all installations.
2. 9in x 9in Brick
Flues previously used for other fuels must be thoroughly
swept. The flue must be lined with a 125mm (5in) flexible
liner. The bottom of the liner should terminate 500mm (20in)
above the base of the builders opening. The flue must be
sealed between the liner and the brickwork at both the top
and bottom.
An approved terminal must be installed.
3. Acid Resistant Liner
A flue constructed of acid resistant liners is satisfactory
provided the size requirements are met. The boiler flue outlet
can be connected to the flue by means of a short length of
125mm (5in) of flue pipe. A seal must be made in the
annular space between the outer face of this flue pipe and
the acid resistant liner.
An approved terminal must be installed.
4. Precast Flues
These must conform to BS 5440 Pt 1 and be correctly
installed without intrusion of cement into the flue passage.
An approved terminal must be installed.
5. Proprietary Flues
A flue of this type must meet the size requirements specified
and be installed in accordance with the flue manufacturers
recommendation and relevant codes of practice.
An approved terminal must be installed.
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