Changes to the Building Regulations and Technical Standards in England, Wales and Scotland

England Regulations have been released (15/12/21) and Scotland & Wales are currently under review. It is the intention that the updates ensure adequate ventilation of all types whilst the energy efficiency of housing is improved at the same time.  As the saying goes, ‘Ventilate when you Insulate’.

This is all part of the Government’s proposals for the Future Homes Standard, which provides a pathway for highly efficient buildings that are zero carbon ready, better for the environments and fit for the future. Implementation of a full technical specification is scheduled for 2025. There are also proposals being discussed to mitigate against overheating in residential buildings.

The below is a Titon summary of the main points, please ensure you read the full documents for full implications

The web page below is available as a downloadable PDF, please click link for a copy.   2022 Ventilation Regulations Update

Updated ADF CPD now available

Following the update to the Building Regulations 2010 (Part F1 Dwellings 2022), Titon has revised its popular ‘Part F 2010 Domestic Buildings Compliance’ CPD presentation to help gain a deeper understanding of the new requirements.

Should you wish to register interest, please click on the link following link – CPD Registration


England - Revised Approved Document F publication issued December 2021 with effective date 15th June 2022

 

What are the changes for background ventilators (e.g. trickle vents in windows or doors)? 

NOTE: All sizes shown are minimum sizes.
New Homes – using Natural ventilation with background ventilators and intermittent extract fans guidance suitable only for less air tight dwellings):
(Formerly System 1 – Intermittent extract fans and background ventilators)
2010 Regulation Guidance 2022 Regulation Guidance
Ventilation amounts, and therefore number of trickle vents required, vary according to a number of criteria including room type, occupancy levels based on bedroom types, floor area of property. These can range from 35,000mm2EA to over 65,000mm2EA. These are now simpler per room amounts;

  • For dwelling with multiple floors:
    Habitable rooms and kitchens: 8,000mm2EA
    Bathrooms: 4,000mm2EA
    Sanitary Accommodation: No minimum
  • For single storey dwellings (e.g flats):
    Habitable rooms and kitchens: 10,000mm2EA
    Bathrooms: 4,000mm2EA
    Sanitary Accommodation: No minimum

There are some sub-rules:

  • Seek expert advice should the dwelling have a single exposed façade, or at least 70% of its openings on same façade, or the kitchen has no windows or façade for vents.
  • Add the 4,000EA to the total if the bathroom has no window or external façade.
  • If kitchen and living room not separate, at least 3 vents of same EA as for habitable rooms should be provided in that space.
  • Total number of vents in habitable rooms and kitchen should be at least 5, or 4 if one bedroom property.
NOTE: The guidance for natural ventilation is only suitable for less airtight dwellings. For the design, sizing and positioning of ventilators to provide effective ventilation using natural ventilation for highly-airtight dwellings expert advice should be sought.

 

New Homes using continuous extract ventilation systems:
(Formerly System 3 – Continuous mechanical extract and (MEV))
2010 Regulation Guidance 2022 Regulation Guidance
Trickle vents should provide 2,500mm2EA in each habitable room Trickle vents should provide 4,000mm2EA in each habitable room
NOTE: The guidance for mechanical extract ventilation is suitable for highly-airtight dwellings only. For the design, sizing and positioning of ventilators to provide effective ventilation using mechanical extract for less airtight dwellings expert advice should be sought.

 

New Homes using mechanical ventilation with heat recovery systems:
(Formerly System 4 – Continuous mechanical supply and extract with heat recovery (MVHR))
2010 Regulation Guidance 2022 Regulation Guidance
No change, trickle ventilators are not required because these are balanced ventilation systems in more energy efficient house designs No change, trickle ventilators are not required because these are balanced ventilation systems in more energy efficient house designs
NOTE: The guidance for mechanical supply and extract ventilation is suitable for any level of airtightness.

 

Existing Homes:
2010 Regulation Guidance 2022 Regulation Guidance
  • Replacement windows should be fitted with trickle vents only if the windows being replaced had vents in them.
  • Habitable rooms: 5,000mm2EA. Kitchen, Utility Room and Bathroom: 2,500mm2EA
  • Addition of a wet room to an existing building: 2,500mm2EA
  • Addition of a habitable room to an existing dwelling: 8,000mm2EA
  • Replacement windows should be fitted with trickle vents regardless of whether the windows being replaced had vents in them or not, if no background ventilation alternative is being installed.
  • Habitable rooms and kitchens: 8,000mm2EA, Bathrooms: 4,000mm2EA.
  • Addition of a wet room to an existing building: 5,000mm2EA.
  • Addition of a habitable room to an existing dwelling (if existing room has less than 5,000mm2EA): 10,000mm2EA.
  • If the existing dwelling has continuous mechanical extract ventilation fitted then 4,000mm2EA is required in habitable rooms.

In all cases there is now an Installation & Commissioning Checklist that needs to be completed and handed over by the installer, this includes background ventilation sign off. This Checklist appears in the Approved Document ‘Part’ F, as opposed to the separate DVCG (Domestic Ventilation Compliance Guide) which has been made obsolete.

 


Documentation for Homes:

2010 Regulation Guidance 2022 Regulation Guidance
Domestic Ventilation Compliance Guide (now obsolete). Home User Guide for new dwellings (4.18 & 4.19)

  • A Home User Guide should be provided for a new dwelling as described in Section 9 of Approved Document L, Volume 1: Dwellings. It should contain a section on ‘Ventilation’ that provides non-technical advice on the ventilation systems provided within the new dwelling.
  • The Home User Guide is in addition to the operating and maintenance instructions. It is intended to be a non-technical overview for the occupiers, and should include some basic details on the operation and maintenance of the system. The operating and maintenance instructions provide further details as required.

Additional information for work in existing dwellings (4.20)

  • When new ventilation is installed in an existing dwelling, information about it should be provided to the building owner in accordance with paragraphs 4.13 to 4.17.

Go to – https://www.gov.uk/government/publications/home-user-guide-template for the Home Energy Guide Template and the Existing Home Ventilation Guide.

NOTE: Information about overheating and the conservation of fuel and power are required under different regulations and guidance is given in Approved Documents O (Overheating) and L (Conservation of fuel and power). Where the system provides more than one function, the owner should be informed of each separate function.
Operating and maintenance instructions (4.13, 4.14 & 4.15)

  • Sufficient information about the ventilation system and its maintenance requirements must be given to the building owner to allow the system to be operated effectively. This should include both design flow rates and maintenance requirements. The information should be provided in a clear manner, for a non-technical audience.
  • A copy of the completed commissioning sheet in Appendix C should be given to the owner of the new dwellings. For existing dwellings Appendix D checklist may be used.
  • The operation and maintenance information should contain specific instructions for the end user on how and when to use the ventilation system, including information on the intended uses for the available fan settings. Information should also be provided to suggest when, and how, the system components should be cleaned and maintained.

What are the changes for Mechanical Ventilation?

2010 Regulation Guidance 2022 Regulation Guidance
System 1:
Background ventilators and intermittent extract fans.
Natural ventilation with background ventilators and intermittent extract fans (guidance suitable only for less airtight dwellings)

Dwellings covered by the guidance – Less Airtight Dwellings

System 3:
Continuous mechanical extract (MEV)
Continuous mechanical extract ventilation

Dwellings covered by the guidance – All Dwellings

System 4:
Continuous mechanical supply and extract with heat recovery
(MVHR)
Mechanical ventilation with heat recovery

Dwellings covered by the guidance – All Dwellings

All systems Highly airtight dwellings:

Dwellings that achieve one of the following.

a. A design air permeability lower than 5m3/(h·m2) at 50Pa.
b. An as-built air permeability lower than 3m3/(h·m2) at 50Pa.

Where the guidance for highly airtight dwellings is followed, dwellings are assumed to have an infiltration rate of 0 air changes per hour.

Airtightness level must be proved if no trickle vents are to be fitted into a ‘Less airtight dwelling’.

Less airtight dwellings:

Those dwellings that are not highly airtight dwellings.

Where the guidance for less airtight dwellings is followed, dwellings are assumed to have an infiltration rate of 0.15 air changes per hour.

 

2010 Regulation Guidance 2022 Regulation Guidance
Table 5.1b – Whole dwelling ventilation rates Minimum whole dwelling ventilation rates Table 1.3 – Minimum whole dwelling ventilation rates Whole dwelling ventilation rates
Number of bedrooms 1 2 3 4 5 Number of bedrooms 1 2 3 4 5
Whole dwelling
ventilation rate (a.b.) l/s
13 17 21 25 29 Minimum ventilation rate
criterion 1 – by number
of bedrooms
19 25 31 37 43
Minimum ventilation rate
criterion 2 – by floor area
0.3 l/s per m2 of internal floor area
Notes:

a. In addition, the minimum ventilation rate should be not less than 0.3 l/s per m2 of internal floor area. (This includes all floors, e.g. for a two-storey building add the ground and first floor areas.)

b. This is based on two occupants in the main bedroom and a single occupant in all other bedrooms. This should be used as the default value. If a greater level of occupancy is expected add 4 l/s per occupant.

A minimum rate of 0.3 litres per second per m2 of internal floor area (this includes all floors, e.g. for a two-storey building, add the ground-floor and first-floor areas).

Notes:

1. Where the dwelling has only one habitable room, a minimum ventilation rate of 13 litres per second should be used.

2. For each additional bedroom, add 6 litres per second to the values in Table 1.3

 

Example of change:
Minimum whole dwelling rate [continuous rate]
Large increase in per bedroom rate could equate to a higher whole house continuous rates. Example below looking at 70m2 .

2010 Regulation Guidance 2022 Regulation Guidance
  • The continuous rate – current
  • Floor area rate = 70m² x 0.3 = 21l/s
  • Dwelling Bedroom rate = 21l/s
  • Boost Rate – Unchanged
  • Floor area rate remains the same = 70m² x 0.3 = 21l/s
  • Dwelling bedroom rate now = 31l/s

 

Noise
2010 Regulation Guidance 2022 Regulation Guidance
1.5 – Mechanical ventilation systems, including both continuous and intermittent mechanical ventilation should be designed and installed to minimise noise.

This includes all of the following:

  • Sizing and jointing ducts correctly
  • Ensuring that equipment is appropriately and securely fixed
  • Selecting appropriate equipment, including following paragraph 1.6

1.6 – For mechanical ventilation systems, fan units should
be appropriately sized so that fans operating in normal
background ventilation mode are not unduly noisy.
This might require fans to be sized so that they do not
operate near the maximum capacity of the fan when
operating in normal background ventilation mode.

1.7 – Account should be taken of outside noise when
considering the suitability of opening windows for
purge ventilation.

Wales – Revised Approved Document ‘Part’ F due for publication very soon after the England equivalent.
Scotland – Revised Technical Standards are due to be published after the England & Wales documents.


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