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The following is a copy of the new Building Regulations -Part 

How to comply with the Building regulations Part L

If you are making changes to your Ch system or installing a new system then it is important that the installer abides by these regulation as quite a lot of are not compiling. 

A good installer will know about these regulations

From 1st April 2002, the Building Regulations for England and Wales – Part L1 – change in some very important ways.

These changes now cover existing homes as well as new properties.

The new Building Regulations reflect the far greater importance the Government is putting on energy efficiency. 

From now on, if you are replacing a boiler or hot water vessel, or controls or making changes to the system,

you will have to demonstrate that you have carried out the work in accordance with the regulations.

This leaflet explains what equipment you will need to install and how you can be confident that you have

complied with these important changes in the way you work.

You will have to install boilers which meet new energy efficiency requirements as measured by the SEDBUK

ratings scheme. 

The level of efficiency varies slightly between fuel types, and we provide details later.

 Minimum efficiency requirements also apply to hot water storage vessels. 

As well as Part L1, Part J has been updated which brings in other aspects of what you do – for example, the positioning

of flue terminals.

Every installation involving a boiler or hot water vessel will need to be certified as being installed and commissioned

by a competent person.

The routes to this are:

i) for a competent person to self-certify the work, using an approved ‘commissioning certificate’.

ii) apply for approval through the local Building Control body.

For the purposes of the new regulations the Government has defined a competent person as:

• A CORGI registered installer for gas installations

• An OFTEC registered technician for oil installations

• A HETAS registered installer for solid fuel systems

• Registered operatives who comply with Building

Regulations – G3 for unvented hot water systems.

This provides a straightforward route for a competent person to self-certify their work using a ‘commissioning

certificate’ such as the Benchmark log book. 

Most installers are familiar with the Benchmark log book, but this has been redesigned to meet the requirements of the

new regulations in consultation with the Government.

There’s a Benchmark log book included with over 90% of

new boilers and unvented hot water storage vessels sold. 

A Benchmark label will be attached to vented cylinders which must also be completed.

Make yourself aware of the key features of the new regulations if you want to be confident that you are complying with them.

You should note that the new Building Regulations still relate to new build properties, and whilst their scope

increases, the principles are similar.

We cannot provide detailed information in this leaflet, only a brief outline of most of the important aspects you will

need to know and understand.

The replacement of a boiler or hot water storage vessel has to meet requirements of the Building Regulations ADL1 from 1st April 2002.

To be confident these requirements are met, this would entail the following:

• A boiler meeting the minimum SEDBUK value shown in the ‘Boiler Choice’ table at the bottom of page 3.

• Insulate all primary pipework, which is altered or replaced and is outside the heated space.

• If the boiler requires a bypass to be fitted, then use an automatic by-pass valve as well as any minimum pipe

length specified in manufacturer’s instructions.

• Warm air heating units should meet the requirements of

BS EN778:1998.

• Insulation should be provided on any ducts that are newly installed or changed.

• For vented systems, replacement copper cylinders should be labelled as conforming to the relevant British Standards, ie BS1566 & BS3198.

• Cylinders labelled type P are only suitable for pumped primary systems. Type G should ideally be pumped but can be used on gravity systems.

• Unvented systems should either be labelled as complying with BS7206 and/or certified by the BBA, WRc or other accredited body.

• Primary Stores should demonstrate compliance by meeting the requirements of the 1999 WMA performance specifications for thermal stores.

• All the pipes connected to a hot water vessel should be insulated for at least a metre in length or up to the point

at which they are concealed to limit summer heat loss from the vessel. This includes the primary flow and return connections and the vent pipe.

Natural Gas 78%

Natural gas – back boilers 75%

LPG 80%

LPG – back boilers 77%

Oil 85%

Oil – combi boiler 82%

Solid fuel Not less than that recommended in the HETAS certification scheme5

• The opportunity should be taken to improve the system controls.

• For fully pumped systems the control system should provide time and temperature control to both the

heating and hot water circuits and a boiler control interlock.

• Fit TRVs on at least those radiators in the sleeping areas if not already fitted.

• If a room thermostat is not fitted, then one should be fitted in a room without a TRV.

• Provide time control if not present by fitting

– A full programmer or

– A standard programmer or

– A mini programmer or

– Time switches.

• No time control is required for the hot water circuit where the hot water is produced instantaneously, such as with a combi boiler.

• Ensure that the controls are wired so that when there is no call for heat from either the heating or the hot 

water circuits the boiler and pump are switched off.

• The preferred option is to convert to a fully pumped system.

• If this is impractical, choose a boiler capable of operating on a semi-gravity system and upgrade the controls to include:

– A cylinder thermostat and zone valve to control the hot water temperature and provide a boiler interlock

– A room thermostat

– A programmer or time switch

– TRVs on the radiators at least in the sleeping areas.

CHECK WITH YOUR SUPPLIER THAT THE BOILER OR HOT WATER VESSEL SELECTED MEETS THESE MINIMUM REQUIREMENTS

For a copy of the comprehensive ‘The Domestic Heating & Hot Water Guide to the Building Regulations 2001 – Part L1’, please visit www.centralheating.co.uk  (and others) and

download a copy. Alternatively call 0845 600 2200 or fax 01926 423 284.

Other sources of information you may find helpful: The Boiler Efficiency Database of boilers that includes the SEDBUK values, is available at www.boilers.org.uk 

The Energy Saving Trust provides the database in a regularly updated publication called ‘The Little Blue Book of Boilers’.

A copy can be obtained by calling 0845 727 7200. Good Practice Guide 302 if followed, will ensure full

compliance for controls with the Regulations. Available from 01926 664258 or via www.heatingcontrols.org.uk 

This leaflet is supported by

The Energy Efficiency Partnership for Homes and the information produced in consultation with the Department

for Transport, Local Government and the Regions

IF Please note  that the web site www.centralheating.co.uk is totally unrelated to this web site www.gascentralheatinguk.com

How to Comply with the Building Regulations Part L