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ADF Update Service - Issue 8...

20th March 2006
Part F 2006 – An Overview

As we are all now aware, the 2006 editions of the Building Regulations ( England & Wales), Parts F, L and P have been published (see www.odpm.gov.uk).

Part F, Ventilation, is now a more comprehensive document which has implications for house-builders, social housing professionals, heating & ventilation engineers, product manufacturers (such as window fabricators) and consultants.

As an initial release we have put together the following points which will be followed at a later date with more detailed technical advice. Due to the fragmented nature of the consultation process, we are comparing the 2006 edition with the 1995 edition and not detailing changes from any of the draft and interim documents. Let us clear the air for you…

Effective Dates

Part F comes into effect on April 6th, however as with Part L, you will be relieved to hear that compliance doesn’t have to be imminent. Due to the short notice, transitional arrangements have been given as follows:

All major building work without full plans approval by 06 April must comply with the 2006 regulations.

Work with approval must begin within 12 months in order to comply with the existing 2002 regulations.

Replacement windows – compliance from 01 October 2006.

Even though this should allow for a gradual movement towards new compliance levels, we would welcome dialogue with organisations to assist them in preparing for the above.

A mainly performance based approach has been adopted and the main changes to the document are listed below:

Part F & Part L Overlap

The link with Part L is more integrated than before. The ventilation provisions have been designed to ventilate buildings having air permeability down to 3m³/h/m² at 50 Pa.

Ventilation Systems

More guidance has been given for domestic mechanical and natural ventilation systems.

There are four ventilation systems outlined in the document:

System 1 – Background ventilators and Intermittent extract fans.
System 2 – Passive stack ventilation.
System 3 – Continuous mechanical extract.
System 4 – Continuous mechanical supply and extract with heat recovery.

Other systems can be used provided it can be demonstrated that they comply with the overall supply and extract requirement set out in the Regulation.

Alternative systems which are not able to comply via the four system types or with the overall supply and extract requirement, must demonstrate to building control that they satisfy the requirement in Appendix A.

Part F appendices give guidance on: Passive stack ventilation system design and installation; Good practice on the installation of fans in dwellings; Minimising ingress of external pollutants into buildings in urban areas.

Background (now Whole Building) Ventilation

Ventilator areas are now described in terms of equivalent area, instead of free area, as it is a better measure of airflow performance. BS EN 13141-1:2004 includes a method for measuring equivalent area.

New dwellings now need to achieve a total background ventilation equivalent area figure, rather than the free area minimums set for each room in the 1995 document. This dwelling figure is calculated based on a number of criteria, such as floor area, number of storeys, and occupancy levels.

This also typically means more background ventilation is required than before. The size of the background ventilators to achieve this will not necessarily have to be bigger; the size of the product will be dependent upon its air flow efficiency.

Ventilators will have to be marked with their equivalent area performance, although building control will adopt a ‘flexible approach’ until October 2006. Ventilators will either be marked with equivalent area in mm² or equivalent area in mm² per metre (where equivalent area of product varies according to length).

All replacement windows should include trickle ventilators, unless the room is ventilated adequately by other installed ventilation provisions. Night latch positions are only to be used in exceptional circumstances. Clarification of the term ‘exceptional circumstances’ is expected soon from relevant trade associations.

Auto-control (e.g. pressure control, humidity control) ventilators must have a manual over-ride to allow them to be closed by the occupant.

Window Openings

This is now called ‘purge’ ventilation, (this was ‘rapid’ ventilation in the 1995 document), and further guidance on openings is given in Appendix C of the document.

Non-domestic Situations

The recommended air supply rate for offices has been increased from 8 l/s per person to 10 l/s per person.

As before, compliance levels for non-domestic buildings vary according to type and most of these situations require reference to other specific technical publications.


Immediate answers to solve compliance issues are not always possible in the same way they may have been with the more straightforward 1995 edition of Part F.

There are many more variables to consider in selecting the correct system and product mix. Once an understanding of the project in hand is established, combined with a reasonable knowledge of the document, product solutions can be very simple.

Titon will be able to offer better performing product to suit these requirements, from background ventilators through to whole house ventilation systems, details of which will be available soon.

Please contact us on 01206 713800 or sales@titon.co.uk for further details. Alternatively monitor www.partf.co.uk or www.titon.co.uk.

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