Class One Flue Liners

 

Dunbrik A1 concrete flue liners systems for domestic chimneys

System details and design guidance:
The Dunbrik A1 Concrete Flue Liner Systems are used in the construction of domestic chimneys suitable for all types of domestic fires. A domestic chimney is a structure made with a minimum of 100mm thick masonry lined with purpose made flue liners.

Householders can burn any domestic fuel including coal and properly seasoned wood or install any domestic gas fire including flame effect fires.

Flue Liners:
Dunbrik concrete liners are made with tongue and socket joints for accurate location and tight jointing. They are manufactured from kiln burnt aggregate and Portland cement and are designed to withstand repeated temperature fluctuations. Flue liners should be joined with Dunseal fire proof mortar paste. Allow approximately 3 joints per cartridge for 200mm liners, 2 joints for 300mm liners and 1 joint for 450mm liners. Any void between flue liners and masonry surround should be filled with Dunfil insulating infill.

Liner Standards:
British Standard BS EN 1857:2003 established performance standards for concrete flue liners for domestic chimneys. Dunbrik liners have been tested by BSRIA and achieved the highest categories in each class as follows:

Dunbrik Type A1 - T600 N1 G D 3

T600	Temperature	nominal operating temperature 600oC
N1	Gas tightness	negative pressure test at 40 Pascal
G	Sootfire resistance	heat shock tested to 1,000oC for 30 minutes
D	Condensate resistance	for dry flue conditions
3	Corrosion resistance	for all domestic fuels (new scrub test for durability)

Flue Liner Ranges:
Dunbrik flue liners are available in three round sizes – 200mm, 300mm and 450mm internal diameter. These allow for the following fireplace opening sizes for burning domestic fuels.

Internal flue diameter mm	Flue cross section 1000 sq mm	Maximum lintel span mm	Recess depth mm	Maximum recess area 1000 sq mm	Typical recess width & height mm
200	31	600	375	265	500 x 550
300	71	800	475	471	685 x 685
450	159	1,100	625	1,060	1,000 x 1,000

For details of lintel span see installation guide
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