System Guide
Certificate No.FM24104
Firebelly stove FB2
woodburner in pewter
domestic flue & chimney systems
Dunbrik A1 Concrete Flue Liners
systems for domestic chimneys
Chimney pot
Weather flaunching on capping
brickwork with drip overhang
A lead flashing & saddle tray at
roof breakout point is not
illustrated
Flue liners encased in
100mm masonry
Voids infilled with Dunfil
Flue liner bend to return
flue run to vertical
Straight flue liners at an angle
to create desired offset
Flue liner bend to offset flue
Throat lintel
Decorative hearth
Dunbrik (Yorks) Ltd
Ferry Lane,
Stanley,
Wakefield,
West Yorkshire.
WF3 4LT
Telephone: 01924 373694
Fax: 01924 383459
email: [emailprotected]
web: www.dunbrik.co.uk
December 2008
B e n e f i t s o f a C h i m n e y
• A chimney adds appeal to a house
• A real fire turns a house into a home
• A natural draught flue promotes a
healthier atmosphere
B e n e f i t s o f D u n b r i kl i n e r s y s t e m s
• Full system from the specialist maker
• Detailed flue estimates prepared
• Systems designed for better flue flow
• Products designed for easier
installation
• Liners meet latest, highest standards
• Expert technical backup
K e y S y s t e m F e a t u r e s
• For domestic fires and stoves
• Can use all domestic fuel:
coal, wood, oil and gas
• Round liners and full unrestricted
bends for better flue flow and easier
offsets
• Tested by BSRIA to European Standard
• Passed highest standard type A1
(T600 N1)
• Sootfire resistant to 1,000oC
L i n e r S i z e s
Sizes for firebacks, open grate fires,
canopy hoods, inglenooks and stoves
• 200mm liners for fireplace openings up
to 500mm by 550mm and stoves
• 300mm liners for fireplaces openings
up to 685mm by 685mm
• 450mm liners for fireplaces openings
up to 1,000mm by 1,000mm
S e r v i c e s
• Flue estimating service
• Installation guides on the web or by
post
• Products available from merchant
stockists in the UK
SYSTEM DETAILS AND DESIGN GUIDANCE
Dunbrik A1 Concrete Flue Linerssystems for domestic chimneys
Example of 300mm round flue with open grate fire
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 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.
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
Performance data
T600 Temperature nominal operating temperature 600o
C
N1 Gas tightness negative pressure test at 40 Pascal
G Sootfire resistance heat shock tested to 1,000o
C for 30 minutes
D Condensate resistance for dry flue conditions
3 Corrosion resistance for all domestic fuels (new scrub test for durability)
UK Building Regulations 2000 ADJ 2002
Dunbrik A1 Concrete Flue Liners meet the minimum standards set in ADJ 2002 and
exceed the requirements for temperature and gas tightness.
Internal flue
diameter
mm
31
71
159
Maximum
lintel span
mm
Recess
depth
mm
Maximum
recess area
1000 sq mm
Typical recess
width & height
mm
200
300
450
600
800
1,100
375
475
625
265
471
1,060
500 by 550
685 by 685
1,000 by 1,000
Flue cross
section
1000 sq mm
domestic flue & chimney systems
Dunbrik A1 Concrete Flue Linerssystems for domestic chimneys
Traditional Fireplace
Inglenook with canopy hood
Courtesy of Potton
Stove with pipe connection
Courtesy of Dunsley Heating
System Angle of
Bend
Component Horizontal
flue offset
mm
Vertical
flue height
mm
200mm
300mm
450mm
22.5 deg
30 deg
22.5 deg
200B pair
with 200L600
with 200L230
with 200L150
300B pair
with 300L230
with 300L150
450B pair
with 450L230
with 450L150
55
add 240
add 85
add 60
125
add 120
add 70
65
add 85
add 55
304
add 554
add 210
add 139
425
add 200
add 120
330
add 215
add 145
Flue Estimates
We can provide you with a flue estimate to suit most configurations of dwelling and flue
size. Please complete our estimate request form or telephone our technical staff with your
details for an estimate.
Components and installation
Components are available from merchant stockists in the UK. Please call 01924 373694 for
your nearest stockist. An installation guide for our products is available on our website
www.dunbrik.co.uk, by fax or post.
Dunbrik A1 Concrete Flue Linerssystems for domestic chimneys
Rotate bend to desired offset direction
Example of 200mm round flue with stove
Typical offset using 2 liner bends
and a 200L600 mm straight liner
SYSTEM DETAILS AND DESIGN GUIDANCE
Bends in Flues
A flue liner bend is used to create an offset to align the flue with house walling or to reach
a chimney pot position. The bends can be rotated to offset the flue in any direction,
avoiding the need for additional sets of bends and further sweeping access. Bends must
not exceed an angle of 45 degrees.
The following table sets out the offset achieved with each pair of liner bends and the
additional offset with each straight liner inserted between the bends.
COMPONENTS
Product
Code
Weight
kg
Internal
Diameter
mm
External
Diameter
mm
Width x
Depth
mm
Straight flue liner - 600mm tall
Straight flue liner - 230mm tall
Straight flue liner - 150mm tall
Liner bend 22.5 degree
Throat lintel 800mm wide
Raft lintel for stove connection
Milner fireback - 450mm
Cannon head chimney pot
Topguard steel cowl 260mm tall
200L600
200L230
200L150
200B
200TL800
200CH1200
450FB
Cann300
TG260
Standard
height flue
liner
200L600
200L230
300L230
450L230
Short flue
liner
200L150
300L150
450L150
Flue liner
bend
200B
300B
450B
Raft lintel
200CH1200
300CH1200
Shapes vary with the different flue
sizes and bend angles
Height
mm
20.4
8.0
5.6
4.9
74
84
38
9.2
1.6
200
200
200
200
-
-
-
260
220
260
260
260
260
-
-
-
300
290
-
-
-
-
800 x 375
1200 x 510
450 x 175
-
-
600
230
150
200
220
150
570
300
260
Taller cannon pots and other designs of chimney pot are also available
Product
Code
Internal
Diameter
mm
External
Diameter
mm
Width x
Depth
mm
Straight flue liner - 230mm tall
Straight flue liner - 150mm tall
Liner bend 30 degree
Throat lintel 1000mm wide
Raft lintel for canopy hood
300mm round straight pot
Topguard steel cowl 350mm wide
300L230
300L150
300B
300TL1000
300CH1200
300RST750
TG350
Height
mm
10.5
6.4
9.3
114
79
51
2
300
300
300
-
-
300
360
360
360
360
-
-
360
-
-
-
-
1000 x 475
1200 x 510
-
-
230
150
189
220
150
750
245
Product
Code
Weight
kg
Internal
Diameter
mm
External
Diameter
mm
Width x
Depth
mm
Straight flue liner - 230mm tall
Straight flue liner - 150mm tall
Liner bend 22.5 degree
Throat lintel 1300mm wide
450mm round straight pot
Topguard steel cowl 500mm wide
450L230
450L150
450B
450TL1300
450RST900
TG500
Height
mm
15.6
11.0
11.1
194
105
3.7
450
450
450
-
450
505
510
510
510
-
510
-
-
-
-
1300 x 625
-
-
230
150
247
220
900
395
Product
Code
Weight
kg
Liner sealant 310ml cartridge
Chimney infill aggregate
Smoke pellets
Flue notice plate
Dunseal
Dunfil
Smoke
Plates
0.6
22
-
-
Dunbrik A1 Concrete Flue Linerssystems for domestic chimneys
All dimensions are nominal. Specifications may be altered without prior notice.
Square liners are also available, details upon request.
Weight
kg
Throat lintel/Gather unit
200TL800
300TL1000
450TL1300
200mm round liner system For fireplace openings up to 500mm by 550mm and
stoves with up to 200mm ext. diameter pipe connection
300mm round liner system For fireplace openings up to 471,000sq mm
450mm round liner system For fireplace openings up to 1,060,000sq mm
Ancillary items
The following may be of assistance in your chimney design and includes references to information sources.
Regulations
A chimney should be designed and built by a competent person with knowledge of regulations and building practices. The detailed
requirements are set out for England and Wales in Approved Document J 2002 (ADJ); there are similar regulations, with some variation, in
Scotland and Northern Ireland. Guidance is also given in NHBC guide, chapter 6.8 and the Lead Sheet Association guide.
Chimney Dimensions and Clearances
A chimney height of 4.5m or over is normally sufficient for flue draught. The depth of the chimney foundations should be the same as any
adjacent wall foundation. In order to provide stability, masonry chimneys should be bonded to, or supported by, adjoining walls of the
building. The masonry should be suitable brick, medium weight blocks or stone and mortar jointed.
The minimum required wall thickness for a masonry chimney is 100mm and 200mm in the wall adjacent to another compartment or
dwelling - see ADJ diagram 2.4. Combustibles must be at least 200mm away from the inside face of the flue liner or have a 40mm air gap
from the outside face of the chimney - see ADJ diagram 2.5.
Chimney Lining
The chimney should be lined with suitable liners and purpose made bends. Joints should be kept to a minimum and sealed with fire
cement. Liner joints should be installed with the tongue pointing downward into the socket to contain moisture and condensate in the flue.
Any voids between liners and masonry should be filled in accordance with manufacturer's instructions.
Bends in Flues
A flue liner bend is used to create an offset to align the flue with house walling or to reach a chimney pot position. The number of bends
should be kept to a minimum for better draw efficiency and to enable sweeping access. They are also used to prevent vertical rain ingress,
but this can also be achieved with a suitable cowl.
Where more than two bends at 45 degrees are used in a flue, additional sweeping access is required by ADJ 1.48. Bends must not exceed
an angle of 45 degrees.
Hearths
A constructional hearth should be made of solid, non-combustible material such as concrete or masonry at least 125mm thick. No
combustible material should be placed underneath a constructional hearth unless there is an air space of 50mm or more or the
combustible material is at least 250mm below the top of the hearth. A finished / decorative hearth should be at least 12mm thick and made
of non-combustible board/sheet material or tiles. For further information refer to ADJ sections 2.22 to 2.29 and 3.40 to 3.42.
Fireplace Recess
The fireplace recess should be constructed of solid non-combustible material. Internal solid walls and jambs should be at least 200mm
thick and cavity walls should have at least 100mm thick leaves and 50mm cavity.
Material in the cavity behind the fireplace should be non-combustible. For an open fire the fireplace recess should be at least 350mm deep.
For solid fuel, ADJ suggests a minimum recess size of 500mm by 550mm using 200mm diameter liners and for larger openings, a flue
cross sectional area of 15% of the face area of the fireplace.
Chimney Stack and Outlets
The height of an unrestrained chimney stack should not exceed 4.5 times the smallest plan dimension of the chimney stack. For heights of
chimney stacks in Scotland consult the Scottish Regulations part F 4-10. Please refer to ADJ section 2.10 and diagram 2.1 for
recommended positions of the flue outlet above the roof. Details of clearances above easily ignitable roof coverings such as thatched roof
are set out in ADJ 2.12 diagram 2.2.
Weather Proofing
A chimney needs to be made weather proof with mortar flaunching around the chimney pot on a brick or concrete capping with drip
overhang. Mortar used for the chimney and flaunching should be resistant to rain and frost. Lead flashings are needed at the junction with
roof tiles and brickwork to prevent water penetration. A saddle tray damp proof course should be installed across the full span of the stack
at the intersection with the roof to prevent water seeping down the chimney. Details of lead saddle trays and flashings are available from
the Lead Sheet Association, tel: 01622 872432.
Air Supply For Combustion
An appliance needs an air supply for combustion so the flue can operate properly. ADJ sets out the air supply requirements; general in
section 1, solid fuel in section 2, gas appliances in section 3, and oil burning appliances in section 4. Typical examples are available from
the Dunbrik website or by post or fax. Some variations occur in the Regulations for Scotland, Ireland and Northern Ireland.
Dunbrik Technical Advice
For further guidance or advice on Dunbrik products contact us, telephone on 01924 373694 or fax on 01924 332878
email at [emailprotected], web site www.dunbrik.co.uk.
General Chimney Design and Regulation Guidance
