Chimney terminals and cowls


The purpose of this standard is to provide the candidate with knowledge of design and installation requirements for terminals and cowls.

CITB has developed this standard in discussion with industry


Minimum 1 day of 6 learning hours

Purpose / scope

The purpose of this standard is to provide the candidate with knowledge of design and installation requirements for terminals and cowls.

The scope of this standard covers: 

  • chimneys and flues for: coal, oil, biomass, wood, and gas
  • regulatory and BS-EN standards for terminations
  • where to locate a chimney termination 
  • how terminals work (chimney pots)
  • how to determine structural integrity
  • proper structural supports and flaunching
  • cross termination contamination (CTC)
  • how not to attach terminals
  • how not to use cowls
  • how to use cowls and flue gas restriction
  • why cowls are not necessary
  • how to define meteorological weather conditions
  • main legislation, codes of practice, building standards, and BS/EN standards, relating to the design and installation of flues, including fire, safety and environment

Occupational relevance

Training delivered against this standard is relevant to the following occupational group(s):

  • operative and craft
  • supervision.

Candidate prerequisites

There are no candidate pre-requisites as part of this standard. However, it would be beneficial if candidates had experience in the relative industry.

Instruction / supervision

As a minimum, course instructors must be able to demonstrate that, in relation to this standard, they have:

  • a train the trainer or instructional techniques course certificate
  • successfully completed training to this standard 
  • at least 2 years relevant industrial experience
  • a verifiable CV.


The following methods may be used in the delivery of this standard:

  • classroom

All materials and equipment must be of a suitable quality and quantity for candidates to achieve learning outcomes and must comply with relevant legislation.

The class size and candidate/instructor ratio must allow training to be delivered in a safe manner and enable candidates to achieve the learning outcomes.

This standard is considered to contain 51 per cent or more theoretical learning.


For the successful completion of training, candidates must complete an end of course practical assessment or knowledge test that measures the learning outcomes and has a pass or fail criteria.

Quality assurance

Quality assurance against this standard will require initial approval of the training organisation and their content mapped to the standard. 

CITB will also conduct an approval intervention, either desk-based or centre visit, to ensure the training organisation can meet the requirements of the Training Standard. 

Approved training organisations (ATOs) will be required to present information on records of training and assessment upon request to CITB for desk-based analysis. They will also be visited annually by the CITB quality assurance team.


There are no mandatory renewal or recommended refreshment requirements for this standard.

Approval date

November 2018

Review cycle

Either on request or in 3 years from approval date.

Learning outcomes

The candidate will be able to: Additional guidance to support learning outcome

Describe the main regulatory and BS-EN standards for terminations


Describe where to locate a chimney termination

Use realistic scenarios with photos and/or illustrations. Without personal information.

Describe how terminals work (chimney pots)

Use animations and sections through chimneys and flues.

Describe how to determine structural integrity


Describe proper structural supports and flaunching


Describe cross termination contamination (CTC)


Describe how not to attach terminals


Describe how not to use cowls

Show good and bad practice photos and/or illustrations. Without personal information.

Describe how to use cowls and flue gas restriction


Describe why cowls are not necessary


Describe how to define meteorological weather conditions

Use videos of different climate/weather, and show the effects on chimney smoke.

Additional information about this standard

Building regulations

The construction and installation of chimneys and flues is covered by UK building regulations in conjunction with relevant European and British standards. See relevant legislation and the NBS (originally National Building Specifications)

  • England and Wales: The building regulations approved document J
  • Scotland: Building regulations technical standards
  • Northern Ireland: Technical booklet L section 3 building regulations Northern Ireland

Statutory guidance

Building control

See Planning Portal for details of document Part L Conservation of fuel and power

  • Approved document L1A: Conservation of fuel and power in new dwellings
  • Approved document L1B: Conservation of fuel & power in existing dwellings
  • Approved document L2A: Conservation of fuel & power in new buildings other than dwellings
  • Approved document L2B: Conservation of fuel & power in existing buildings other than dwellings


See relevant government legislation

  • Clean Air Act 1956
  • The Clean Air (Height of Chimneys) (Exemption) Regulations 1969
  • Health and Safety at Work etc Act 1974
  • Provision and Use of Work Equipment Regulations 1998 (PUWER)
  • Control of Substances Hazardous to Health 2002 (COSHH)
  • Party Wall Act 1996
  • Consumer Rights Act 2016
  • Supply of Goods and Services Act 1982

Health & Safety Executive (HSE)

There is a lot of HSE information relating to chimneys and ventilation systems. Some examples are:

Fire safety

Working at height


You can see many British/European standards and codes of practice at BSI.

  • Appliances

  • BS 1251: 1987 Specification for open fireplace components.
  • BS 5440-1: 2008 & 2:2009. Flueing and ventilation for gas appliances (70 kW net).
  • BS 6762-2:1991. Code of practice for solid fuel fired heating in park homes and caravans.
  • BS 6880. Parts 1,2&3 1988. Code of practice for low temp hot water heating systems (45kW+).
  • BS 7977-1&2: 2009 Spec’n domestic gas appliances. Radiant. Combi/gas fire/back boiler (Pt2). 
  • BS EN 483: 2000 Gas-fired central heating boilers. Type C, max 70kW. 
  • BS EN 509: 2000 Decorative fuel-effect gas appliances. 
  • BS EN 13384-1 & 2: 2015 Chimney thermal/fluid dynamic calcs for one/more heating appliances
  • BS EN 15287+A1: 2010. Design, install & commission chimneys. Non & roomsealed appliances
  • Alarms

  • BS EN 50291-1: 2010. Domestic electrical apparatus for detecting carbon monoxide.
  • Chimneys and flues

  • BS 715: 2005 Specification for metal flue boxes for gas-fired appliances (max 20kW).
  • BS 4207:1989. Code of practice for monolithic linings for steel chimneys and flues.
  • BS 5854:1980. Code of practice for flues and flue structures in buildings.
  • BS 6999:1989. Specification for vitreous-enamelled low carbon steel flue pipes
  • BS 5871: Parts 1,2,3: 2005 & Part 4: 2007. Specification for installation of appliances
  • BS EN 1443: 2003. General requirements for chimneys 
  • BS EN 1856 – 1&2: 2009. Metal chimneys, products (Pt1) and liners/flues (Pt2)
  • BS EN 1857: 2010 Concrete flue liners. 
  • BS EN 1858: 2008 +A1:2011 Chimneys, components, and concrete flue blocks. 
  • BS EN 1993-3-1: 2006. Eurocode 3. Design of steel structures. Towers, masts and chimneys
  • BS EN 12446: 2011. Concrete outer wall elements.
  • BS EN 13084-1,2,4,5,6,7 2007. Free-standing chimneys. General, concrete, brick, and steel. 
  • BS EN 14241-1: 2013. Chimney elastomeric seals and sealants. 
  • BS EN 14471: 2013+A1:2015. Chimney systems with plastic flue liners. 
  • BS EN 16497-1&2: 2015. Concrete chimneys. Non-balanced (Pt1) and balanced (Pt2) flues.

Requirements and testing

  • BS EN 1457-1&2: 2012. Clay/ceramic flue liners, dry (Pt1) and wet (Pt2).
  • BS EN 1806: 2006 Clay/ceramic flue blocks for single wall chimneys.
  • BS EN 1859: 2009 +A1:2013 Metal chimney test methods. 
  • BS EN 13063-1&2:2005 & 3:2007. Clay/ceramic flue liners. Sootfire resistance. 
  • BS EN 13069: 2005. Clay/ceramic outer walls. 
  • BS EN 13216: 2004. Test methods for chimney systems. 
  • BS EN 13502: 2002. Clay/ceramic flue terminals.  
  • BS EN 14297: 2004 Freeze-thaw resistance tests for chimney products
  • BS EN 14989-1&2: 2007. Metal chimneys.
  • BS EN 16475-1,2,3,4,5,6&7. 2016/2017. Chimneys. Accessories. Silencers, Fans. Draught regulators, standstill opening devices, combi-secondary air devices. Access parts. Rain caps.