Hetas Guide Part 3

FACTORY MADE CHIMNEYS AND CHIMNEY LINING SYSTEMS

A. INTRODUCTION

1. CHIMNEYS AND FLUES

The details on the factory made chimney and flue products listed in this section have been provided with the help of the British Flue and Chimney Manufacturers Association. In the absence of a HETAS testing scheme for certification of chimney and flue systems, pending the publication of European standards, the current status of each product has been declared to HETAS by the manufacturer.
Many of the products listed are covered by recognised independent test certification. Where a claim is made that the product is manufactured to a British Standard or meets Building Regulations 2000 for England and Wales by satisfying the recommendations of the current (1st April
2002) edition of Approved Document J or otherwise by demonstration of compliance, this claim is the responsibility of, and should be confirmed with, the manufacturer prior to purchase. It should be understood by purchasers and specifiers that a claim recorded in the
Approval Status column as "Manufacturer claims to BS EN xxxx", although coming within the Trade Descriptions Act, is a claim of the manufacturer alone and not endorsed by HETAS or any independent Certification/Approval body.
Where the claim in the Approval Status column quotes a BSI Kitemark, BBA, BSRIA, Wimlas, CSTB, HETAS or TÜV certificate number this is an indication that that product has been independently type tested and approved by a body entitled to engage in third party certification and product monitoring.
Publication in this Guide does not endorse such manufacturers' claims.

2. SELECTION OF A CHIMNEY OR FLUE SYSTEM

1. The flue size of the system and arrangement are determined by the type of appliance to be used and its location. The siting of a chimney should minimise the effect of emissions on the dwelling itself and on neighbouring buildings. Whatever chimney arrangement or products used must satisfy Building Regulations and the recommendations of British Standard BS 6461: Part 1,1984 (1998) for masonry chimneys and flue pipes, or BS 7566:1992 (1998) for factory-made metal chimneys to BS 4543 for domestic appliances.
2. Flue sizing should be according to sections 2.4 to 2.6 of Approved Document J. An internal flue size of 200mm square or round is commonly specified as this size will allow most types of stove or standard open fire to be fitted. If an inglenook or large open fire is proposed it is necessary to have a larger flue size, which can be calculated according to Approved Document J, section 2.7.
3. During construction of a new house the chimney is usually built "traditionally" in brick or blockwork surrounding clay, refractory concrete, pumice, or ceramic flue liners. It is also possible to use a chimney block or factory made metal chimney system.
4. A new chimney can be added to an existing house quickly and economically using a factory made metal or chimney block system.
5. Rebuilding or relining an existing chimney requires specialist advice. Providing the existing chimney structure is sound, there is a wide choice of factory made chimney relining systems that can be used. Fire-resistant precast concrete, terracotta and pumice flue liners or ceramic liners offer the most permanent solution, providing the existing chimney openings are big enough to take the correct flue size to suit the proposed appliance.
Cast In-Situ lining systems are also available (see Part 3 Section J) which have been tested by an independent body, such as HETAS, to meet the appropriate requirements of BS EN 1857:2003 at the T450 N2 D3 G level using tested materials which are installed under an accepted Code of Practice. It is desirable for such installations to be monitored under a QA inspection system independently monitored.
Double skin flexible stainless steel flue liners offer an alternative answer if access is difficult or the existing chimney is unable to accept other types of liners. However, these flexible liners, whilst being easier to install and replace, are not permanent and significant periods of slow burning with solid fuels or infrequent chimney sweeping can cause corrosion damage which reduces the expected life to less than 5 years.
Under no circumstances should a single skin flexible liner designed solely for use with gas fires be used with a solid fuel burning appliance.
6. The efficiency and life expectancy of any chimney is dependent on correct use and maintenance. Masonry and precast chimney products whilst usually offering long life and high resistance to risk of corrosion, tend to involve more installation work, when compared with metallic chimney systems.
Metal liners and insulated metal chimneys offer fast and convenient installation. However, they are less resistant to damage by corrosion particularly if subjected to abuse or inadequate cleaning.
Allowing soot or condensate deposits to accumulate in metal lined chimneys and also prolonged periods of burning solid fuel slowly in slumbering conditions, particularly on closed appliances, can cause high concentrations of corrosive condensates to build up and attack the metal liner. This situation can considerably reduce the life of the flue lining.
7. Prefabricated factory made fireplace recess components such as throat forming lintels, gather units or appliance chambers are available with most systems.
8. The manufacturer's installation and user instructions must be followed. Members of the BFCMA are able to provide full details and free advice on their products, including layout design and estimating services. The British Standard BS 6461 : Part 1 : 1984 (1998) is the ‘Code of Practice for masonry chimneys and flue pipes’, and BS 7566 : 1992 (1998) is the ‘installation of factory made chimneys to BS 4543 for domestic appliances’.

3. CHIMNEY MAINTENANCE AND SWEEPING

1. The flueways in the chimney and flue pipe must be cleaned regularly to remove all soot deposits and prevent blockage of the flue. This should be done at least twice a year, preferably before the heating season to check that the flue has not been blocked by bird's nests for example and also at the end of the heating season to prevent soot deposits from resting in the chimney during the dormant period.
2. When using a new installation the flueways should be checked at least monthly, so that an adequate cleaning cycle can be determined in relation to the use of the appliance. The risk of heavy tar and soot deposits is greatly increased if unsuitable fuel is burnt, which can result in a chimney fire or corrosion damage.
3. Sweeping with a brush and rods is the only recommended method of cleaning, because other materials such as mortar in old flues, loose bricks or bird's nests etc. can block a flue. For this reason vacuum or chemical chimney cleaners cannot be recommended as an alternative to sweeping. Some chemical cleaners can corrode metal in the chimney and appliance.
Sweeping brushes must be made from suitable bristle and be of the appropriate diameter for the area of the flue being swept. They must also be fitted with a ball end or free running wheelboss to prevent scraping or damaging the flue lining particularly at bends.
4. HETAS recommends the use of a qualified chimney sweep who will usually be a member of the National Association of Chimney Sweeps, or Guild of Master Sweeps who can give an inspection and sweeping certificate. HETAS Approved Sweeps are listed in Section E. Many chimney manufacturers give specific advice on what sweeping brushes to use with their products. This advice should be followed.
5. As recommended by British Standards all chimneys should be checked annually for signs of wear and tear such as flashings, supports, terminals and any other exposed areas of the chimney, so that repairs can be carried out as necessary.
6. If at any time smoke or fumes are apparent or suspected to be escaping from the appliance or chimney, stop using the appliance at once and get advice immediately from the installer and or fuel supplier. Do not use the appliance or burn any fuel until the installation has been checked and passed as being safe.

B. CHIMNEY BLOCK SYSTEMS

Usually made from lightweight insulating concrete or pumice, the blocks are designed for quick installation and incorporate a built in or separate flue liner. The chimney block system must satisfy Building Regulations. This can be achieved by meeting the
requirements of the 2002 Edition of Approved Document J that specifies flueblocks whose performance is at least equal to that corresponding to the designation T450 N2 S D3, as described in BS EN 1443:1999 (now 2003 with the changed designation T450 N2 D3 Gxx where xx is the necessary separation from combustible materials).
Reference is made to the example of clay flueblocks at least meeting the requirements for Class FB1 N2 as described in BS EN 1806:2000.
In the absence of there being a UK Notified Body covering testing to these standards, manufacturers may seek to have their chimney block systems tested by a recognized independent body that provides a certificate confirming the performance levels on the basis of testing to the relevant procedures specified in the appropriate standard. Recognised testing bodies might include the BBA, BRE Certification, BSRIA and CERAM. Other solutions for demonstrating compliance with the Building Regulations may be acceptable as defined in the Approved Document J.
It is recommended that the validity of certification for the liners or evidence of compliance with Building Regulations be checked prior to purchase.
*Chimney Block Systems flue sizes marked with an asterisk are those covered by a BBA Certificate. Other sizes, not asterisked, have been declared by the manufacturer to be produced to the same specification.

Manufacturer	Product Name	Flue sizes	Approval Status
Schiedel-Isokern Chimneys	Isokern DM	250, 300, 350mm round	BBA cert. no. 86/1595
Anki Chimney Systems	Anki Single Module	160, 200 mm round	BBA cert. no. 87/1886

C. PREFABRICATED CHIMNEY SYSTEMS

Made in interlocking sections with a stainless steel outer casing surrounding high performance insulation and a flue liner made of stainless steel. Some systems have a ceramic or refractory concrete flue liner which offers better resistance to corrosion.

These systems must have a British Standard Kitemark to the current BS 4543: 1990 (1996)

Part 3 deals only with suitability for oil firing systems) or a BSRIA certificate or similar test reporting e.g. by TÜV that indicates the product can satisfy Building Regulation requirements with respect to the burning of solid fuel. The Approval Status listed for the products was correct at the time of printing but it is recommended that the manufacturer be consulted on the current approval status prior to specification or purchase of the product.

The metal lined systems should give a normal life of 10 to 15 years or more when correctly installed, operated and maintained. However, prolonged periods of slow burning particularly using solid fuels, combined with inadequate cleaning of the flueways can cause corrosion damage which may reduce the expected life of the liner. If there is a risk that these conditions can occur the non-metallic lined systems are a better choice and under normal use should give a life in excess of 20 years.

*Flue liners manufactured from Stainless Steel. Flue sizes marked with an asterisk are those tested for Kitemarking or by BSRIA or TÜV. Other sizes, not asterisked, have been declared by the manufacturer to be produced to the same specification.

Manufacturer	Product Name	Flue sizes	Approval Status
H. Docherty Ltd	Chimaster MF	130, 150, 180,200, 230, 250, 300mm round	Tested to BS 4543 parts 2 & 3, BSRIA Cert. Nos, 14146/3., 4 & 7
Kedddy-Poujoulat (UK) Ltd.	Therminox	125, 150, 180, 200, 250, 300, 350, 400, 500, 600mm round	Kitemark to BS 4543: 1990 Parts 2 & 3. Licence no. 26157
Rite-Vent Ltd.	ICS	80, 100, 130, 150, 180*, 200mm round	Kitemark to BS 4543: 1990 Parts 2 & 3. Licence no. 6518
Rite-Vent Ltd.	ICID Lite	125, 300mm	TÜV Süddeutschland Bau Und Betreib Report no. A 1053.00/02
Selkirk Manufacturing Ltd	SMW Chimney system	127, 152, 178*, 203mm round	Kitemark to BS 4543: 1990 Parts 2 & 3 Licence no. 5656
Midtherm Flue Systems Ltd	HT Plus	130, 150, 180, 200, 250, 300mm round	BSRIA Cert Nos, 17407/1
Powrmatic Ltd	System 250	125, 150,175, 200,250, 300, 350, 400, 450, 500, 550, 600mm	Kitemark to BS4543: 1990 Parts 2&3. Licence no. 7700

D. FLUE LINERS - FOR BUILDING NEW CHIMNEYS OR FOR RELINING

Made from fire clay, ceramic, pumice or refractory concrete, these liners usually have spigot and socket joints for ease of installation and efficient performance.

All liners must satisfy Building Regulations. This can be achieved by meeting the requirements of the 2002of Approved Document designation is changed to T450 N2 D3 G)” ‘J' that specifies “liners whose performance is at least equal to that corresponding to the designation T450 N2 S D3, as described in BS EN 1443: 1999 (now 2003 in which the

Reference is made to the example of clay liners meeting the requirements for Class A1 N2 or Class A1 N1 as described in BS EN 1457: 1999 (now 2003) that replaces BS 1181 and concrete liners meeting the requirements for the classification Type A1, Type A2, Type B1 or Type B2 as described in BS EN 1857:2003).

In the absence of there being a UK Notified Body covering testing to these standards, manufacturers may seek to have their liners tested by a recognized independent body that provides a certificate confirming the performance levels on the basis of testing to the relevant procedures specified in the appropriate standard. Recognised testing bodies might include the BBA, BRE Certification, BSRIA and CERAM. Other solutions for demonstrating compliance with the Building regulations may be acceptable as defined in the Approved Document J.

It is recommended that the validity of certification for the liners or evidence of compliance with Building Regulations be checked prior to purchase.

When installed, used and maintained correctly these types of liners are considered to provide a life equal to that of the dwelling. Specific guidance is given in the Approved Document J in relation to the installation of liners and construction of masonry chimneys

*Flue Liner flue sizes marked with an asterisk are those covered by a BBA/BSRIA Certificate. Other sizes, not asterisked, have been declared by the manufacturer to be produced to the same specification.

Manufacturer	Product Name	Flue sizes	Approval Status
Schiedel-Isokern Chimneys	Isokern liners	130, 150, 170, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600, 700, 900 up to 1000mm round and 150 x 260 mm oval	BBA cert. no. 86/1595
Anki Chimney Systems	Anki Round Liners	130, 150, 170, 200, 250, 300, 350mm round and150x260mm oval	BBA cert. no. 87/1886
Anki Chimney Systems	Anki Block Liners	130, 160, 200*, 225, 300, 350mm (for new chimneys requiring no back fill)	BBA cert. no. 87/1886
Kedddy-Poujoulat (UK) Ltd	Kedddy flue linings	225mm round, 200, 225, 250, 280, 300, 355, 400, 435, 500mm square and 300x420 rectangular. Special sizes made to order	Manufacturer claims meets Building Regulations
P.D. Edenhall Ltd	Marflex ML Flue liners	225mm round, 200, 250mm square	Manufacturer claims meets Building Regulations
P.D. Edenhall Ltd	Marflex MLC Flue liners large flue liners	380x560, 450x560, 550x660mm rectangular	Manufacturer claims meets Building Regulations

E. DOUBLE SKIN FLEXIBLE CHIMNEY RELINING SYSTEMS

Made from stainless steel these liners have a spirally wound double skin construction that has a smooth inner. These flexible liners are specifically designed for use with solid fuel.Double skin liners are not to be confused with single skin flexible liners which are designed solely for use with gas fires which must not be used with solid fuel appliances under any circumstances.

All liners must satisfy Building Regulations. This can be achieved by meeting the requirements of the 2002
of Approved Document changed designation T450 N2 D3 G)” ‘J' that specifies “liners whose performance is at least equal to that corresponding to the designation T450 N2 S D3, as described in BS EN 1443: 1999 (now 2003 with the

At present there are no British Standards or British Board of Agrément approvals for this type of product. Proof of suitability has therefore to be made by a recognised test authority. Currently the CSTB, and TÜV have recognised testing approval schemes. These certificates can be used as evidence to satisfy Building
Regulations approval. The current validity of their certification should be checked prior to purchase. Additional guidance is given in the Approved Document J of the Building Regulations 2000 (paragraph 2.20), which came into effect on 1st April 2002.

These liners are for relining an existing brick chimney and are not to be used as a liner for new masonry chimneys. Liners for new build are referenced in section D. These liners should give a normal life of 10 years or more when correctly installed, used and maintained. However, these flexible liners whilst being easier to install and replace are not permanent and prolonged periods of slow burning particularly using solid fuels, combined with inadequate cleaning of the flueways can cause corrosion damage which reduces the expected life of the liner to less than 5 years. If there is a risk that these conditions can occur the non-metallic liner systems are recommended and under normal use should give a life equal to that of the dwelling.

*Chimney Relining System flue sizes marked with an asterisk are those covered by the CSTB/BSRIA or TÜV Certificate. Other sizes, not asterisked, have been declared by the manufacturer to be produced to the same specification.

Manufacturer	Product Name	Flue sizes	Approval Status
H. Docherty Ltd	Fire Flexmaster	125, 150, 175, 200mm round	BSRIA Type Test Cert. No. 14406/1
Schiedel-Isokern (UK) Ltd	SupaFlex	126, 154, 180, 200, 230, 250, 300*mm round	CSTB cert. no. 11/99-274
Kedddy-Poujoulat (UK) Ltd	Tubinox L316	125, 155, 180, 200, 230, 250, 300*mm round	CSTB cert. no. 11/97-258
Kedddy-Poujoulat (UK) Ltd	Tubinox FL316	125, 155, 180, 200, 230, 250, 300*mm round	CSTB cert no 11/97-257
Kedddy-Poujoulat (UK) Ltd	Tubinox HR904	125, 155, 180, 200, 230, 250, 300*mm round	CSTB cert no 11/97-258
Rite-Vent Limited	Chimflex LW	110, 120, 125, 130, 140, 150, 155, 160, 170, 180, 200, 220, 230, 250, 280, 300, 355, 400mm round	TÜV Süddeutschland Bau Und Betreib Report no. A 1055.00/02
Rite-Vent Limited	Chimflex SB	110, 120, 125, 130, 140, 150, 155, 160, 170, 180, 200, 220, 230, 250, 280, 300, 355, 400mm round	TÜV Süddeutschland Bau Und Betreib Report no. A 1056.00/02
Rite-Vent Limited	Turboflex	110, 120, 125, 130, 140, 150, 155, 160, 170, 180, 200, 220, 230, 250, 280, 300, 355, 400mm round	TÜV Süddeutschland Bau Und Betreib Report no. A 1055.00/02
Topstak Chimney Specialists Ltd	Multiflex 316	125, 154, 180, 200, 225, 250, 300*mm round	CSTB cert. no. 030.01/02-01
Topstak Chimney Specialists Ltd	Multiflex 904	125, 154, 180, 200, 225, 250, 300*mm round	CSTB cert. no. 030.01/02-01
Expo UK Ltd	Expo HG (316L steel) Expo TCR (904L steel)	125, 130, 150, 155, 175, 180, 200, 225, 250, 300 mm round	TÜV Süddeutschland Bau und Betreib report no A 102-00/02
Midtherm Flue Systems Limited	Euroflex (in 316L and 904L steel)	125, 150, 175, 200, 230, 250, 300 mm round	TÜV Süddeutschland Bau und Betreib report no A 102-00/02
Selkirk Manufacturing Ltd.	Selflex TS (316Ti)	125, 152, 154, 180,203, 229, 254, 300 mm round	CSTB cert. no. 038-02/02-01
Selkirk Manufacturing Ltd.	Selflex TSE (904L)	125, 152, 154, 180, 203, 229, 254, 300 mm round	CSTB cert. no. 038-02/02-01
Selkirk Manufacturing Ltd.	Regaflex S(316Ti)	125, 150, 180, 200mm round	CSTB cert. no. 2.038-02/02-01
Selkirk Manufacturing Ltd.	Regaflex CR(904L)	125, 150, 180, 200mm round	CSTB cert. no. 2.038-02/02-01
Fenton’s Flue and Chimneys	Stackflex (316Ti)	125, 150, 180, 200mm round	CSTB cert. no. 1.038-02/02-01
Fenton’s Flue and Chimneys	Stackflex (904L)	125, 150, 180, 200mm round	CSTB cert. no. 1.038-02/02-01

F. FLUE PIPES - FOR CONNECTING APPLIANCE TO CHIMNEY

Made from either 1 mm thick 316 grade stainless steel or vitreous enameled low carbon steel in a variety of finishes and colours, these pipes are available with a choice of bends and accessories.
Stainless steel flue pipes must satisfy Building Regulations via meeting the recommendations of Approved

Document J or the recommendations of BS 6461: Part1,1984(1998), or BS 7566:1992 (1998). Vitreous enameled flue pipes should meet BS 6999 1984(1998). The current validity of their Agrément Certificate or evidence of compliance with Building Regulations should be checked prior to purchase.

These flue pipes should give a normal life equal to that of the heating appliance when correctly installed, used and maintained. However, prolonged periods of slow burning particularly using solid fuels, combined with inadequate cleaning of the flueways can cause corrosion damage which may reduce the expected life of the product.

These products must only be used to connect a heating appliance to a chimney and not as a flue liner within a chimney, unless the relining system is independently certified as suitable for this purpose and has an equivalent designation to T450 N2 S D3 described in BS EN 1443:1999 (now 2003 with the changed designation T450 N2 D3 Gxx).

Vitreous enamel stove Flue Pipes

Manufacturer	Product Name	Flue sizes	Approval Status
H. Docherty Ltd	Vitmaster	100, 125, 150, 175mm round	Manufacturer claims to BS 6461 Part 1
MMF Ltd.	Proheat	4, 5, 6, 7, 8 ins	Tested to BS 6999:1989. BSRIA report No. 17721/1
MMF Ltd.	Uni-Vit	4, 5, 6, 7, 8 ins	Tested to BS 6999:1989. BSRIA report No. 17721/3

1mm Thick 316 Stainless Steel Flue Pipes

Manufacturer	Product Name	Flue sizes	Approval Status
Rite-Vent Limited	Prima Plus	125, 150, 180, 200mm round	Manufacturer claims meets Building Regulations
MMF Ltd.	Proheat	5, 6, 7, 8 ins	Meets 2000 Building Regulations. BSRIA report No. 17721/2 and 17721/4
MMF Ltd.	Proheat Streamline	130, 150mm	Meets 2000 Building Regulations. BSRIA report No. 17721/2 and 17721/4

G. NON METALLIC CHIMNEY LINING SYSTEMS

There is a variety of different systems where a non-metallic lining is applied to the flue within an existing chimney. In most cases these systems use a special formulation of ceramic or concrete based materials that are installed by specialist contractors that are approved or registered by the lining manufacturer.

All liners must satisfy Building Regulations. This can be achieved by meeting the requirements of the 2002 of Approved Document changed designation T450 N2 D3 G)”. ‘J' that specifies “liners whose performance is at least equal to that corresponding to the designation T450 N2 S D3, as described in BS EN 1443: 1999 (now 2003 with the

At present there is no British or European Standard that specifically covers these types of chimney lining systems. It is therefore necessary that the suitability of the material and its application as a flue lining is proven by having a recognised independent product approval certification that is accepted as demonstrating compliance with Building Regulations.

Recognised forms of certification include those issued by the BBA, BSRIA, Wimlas or other recognised independent testing authorities that issue Test Approvals that are accepted as demonstrating compliance to Building Regulations using recognised test and assessment procedures based upon British or European Standards. Such certificates should be confirmed with the issuing body as indicating that the product meets Building Regulations.

The Eldfast system listed below is a special formulation of ceramic binders and fine aggregates that are designed to provide a durable flue lining in a sound masonry chimney. This lining system is for relining an existing brick chimney and is not to be used as a liner for new masonry chimneys. Liners for new build are referenced in section D.The system must be applied in accordance with the manufacturers instructions by an installer who is Registered by the manufacturer.

When installed, used and maintained correctly an extended life can be expected. However, it is essential that the installation is carried out correctly ensuring that the minimum thickness of lining is applied and that the subsequent flue area is suitable for use with the fuel-burning appliance. This form of lining must not be relied upon to provide support to a structurally unstable chimney. The thermal insulation of a chimney lined in this way is greater than an unlined or conventional masonry chimney. It is the responsibilty of the customer, installer and specifier to ensure that the lining and installation as a whole complies with current Regulations and is covered by the appropriate approval at the time of installation.

Manufacturer	Product Name	Approval Status
Landy Vent (UK) Ltd	Eldfast chimney lining system	BSRIA Type Test* cert. no. 15024

* (The material and its application has passed performance testing carried out by BSRIA
using test procedures based upon the draft European Standard prEN1857 to
ascertain performance levels as defined in BS.EN 1443: 1999)

H. RIGID STAINLESS STEEL CHIMNEY RELINING SYSTEMS

Made from 0.6 and 1mm thick sections of high grade stainless steel these rigid liners and bends have spigot and socket joints for ease of installation and efficient performance.

All systems must satisfy Building Regulations. This can be achieved by meeting the requirements of the 2002 Edition of Approved Document J that specifies liners whose performance is at least equal to that corresponding to the designation T450 N2 S D3 as described in BS EN 1443:1999 (now 2003 but with a changed designation of T450 N2 D3 G).

At present there are no British Standards or British Board of Agrément approvals for this type of product. Proof of suitability has therefore to be made by a recognized test authority. Guidance is given in the Approved Document J of the Building Regulations 2000 (paragraph 2.20) which came into effect on 1st April 2002.

These liners are for relining an existing brick chimney and are not to be used as a liner for new masonry chimneys. Liners for new build are referenced in section D.

These liners have a thickness of either 0.6 or 1mm. They should have a life expectancy of 10 years or more when correctly installed, operated and maintained. However, prolonged periods of slow burning particularly using solid fuels, combined with inadequate cleaning of the flueways can cause corrosion damage which may reduce the expected life of the liner. All components recommended by the manufacturer, such as spacers, must be used. The manufacturer's installation instructions must be adhered to.

Manufacturer	Product Name	Flue sizes	Approval Status
Rite-Vent Limited	Prima Plus 0.6mm	125, 150, 180, 200, 250, 300mm round	TÜV Süddeutschland Bau und Betreib report no. A 1117-01/03
Rite-Vent Limited	Prima Plus 1.0mm	125, 150, 180, 200, 250, 300mm round	TÜV Süddeutschland Bau und Betreib report no. A 1117-01/03

J. CAST IN-SITU CONCRETE LINING SYSTEMS

The cast in-situ concrete lining system is one of a number of methods of lining a domestic chimney. It is generally used to line chimneys of masonry construction. An inflatable rubber former is inserted in the flue of the chimney and pressurised until it reaches the diameter required, centralised and the void formed between the liner and the chimney filled with an approved mix of lightweight insulating concrete. Once the concrete has cured and is hard the former is deflated and removed

Building Regulations 2000 Approved Document J of 1st April 2002 under paragraph 2.20 a) ii permits the use of
a cast in-situ flue relining system where the material and installation procedures are independently certified as suitable for use with solid fuel burning appliances.
In the absence of other certification and a specific Standard for this type of system HETAS is supervising Type Testing at the Gastec at CRE laboratory to the appropriate clauses of BS EN 1857:2003. It is required that a lining, suitable for use with solid fuel, meets category T450 N2 D3 G and that the materials are specified, prepared and installed in accordance with an approved Code of Practice supported by an independently monitored QA system. Currently the NACE system has been Type Tested and Approved by HETAS who also monitor the NACE QA system. Other systems will be approved in due course and listed in the updated web-site versions of this Guide.

SPECIAL NOTES When installed, used and maintained correctly a long life can be expected. However, it is essential that the

installation is carried out in accordance with the Code of Practice upon which approval is based. This requires that the former is properly spaced to maintain the correct minimum thickness of concrete. Breaking into the chimney at bends in the flue-way is necessary to ensure correct spacing is maintained and to prevent the former from touching the chimney wall. Failure to do this can result in the concrete lining being too thin or incomplete, which will reduce the life of the system and require major repair work.

The appropriate flue size must be provided to suit the proposed or potential appliance to be fitted. These linings must not be relied upon to provide support to a structurally unstable chimney. The thermal insulation of a chimney lined in this way is greater than an unlined masonry chimney. It is the responsibility of the customer, installer and specifier to ensure the lining and the installation as a whole conforms with current regulations and is covered by the appropriate approval at time of installation.

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