Building Regulations

Building Regulations(sometimes known as building standards) define how a new building or alteration is to be constructed. The regulations cover a number of areas including:

Safety
Fire risk
Energy efficiency
Accessibility
Ventilation
Security

Building Regulation approval may be required even if Planning Permission is not. In England and Wales, as well as Scotland, approval is granted by the building control officers of local authorities. They are generally separate from the planning officials. You can also discuss the suitability of various building elements with building control to ensure the design is compliant in all respects.

Even though the alterations you propose may not require either planning or building control approval, you may still be required to meet the Building Regulations appropriate to the changes. Advice should be sought from your local Building Control office.

Each country in the UK is responsible for its own building regulations. The regulations are usually set out in terms of high level, functional requirements. They are supported by technical documents which set out detailed practical guidance on compliance with the regulations (for example, Approved Documents in England).

The official technical guidance for each country in the UK, and also Ireland, can be accessed via the links below:

Below you can find information on how building regulations inform glass specification in the UK. Use the drops downs to select the country where your project/building is located for country-specific guidance.

England

The Department for Levelling Up, Housing and Communities (DLUHC) is responsible for building regulations in England, which exist to ensure the health and safety of people in and around buildings, and the energy efficiency of buildings. The regulations apply to most new buildings and many alterations of existing buildings in England, whether domestic, commercial or industrial.

General public users and professional users can access building regulations guidance, including the Approved Documents and associated guidance from the Planning Portal at: https://www.gov.uk/planning-permission-england-wales.

The regulations apply to most new buildings and many alterations of existing buildings in England, whether domestic, commercial or industrial. Practical guidance on ways to comply with the functional requirements in the Building Regulations is contained in a series of Approved Documents which are to be read alongside each of the 'parts' in Schedule 1 to the Building Regulations.

Each document contains: general guidance on the performance expected of materials and building work in order to comply with each of the requirements of the Building Regulations; and practical examples and solutions on how to achieve compliance for some of the more common building situations.

To view all of the Approved Documents and related publications click here.

These are the Approved Documents for England:

Approved Document A - Structure
Approved Document B - Fire safety
Approved Document C - Site preparation and resistance to contaminates and moisture
Approved Document D - Toxic substances
Approved Document E - Resistance to sound
Approved Document F - Ventilation
Approved Document G - Sanitation, hot water safety and water efficiency
Approved Document H - Drainage and waste disposal
Approved Document J - Combustion appliances and fuel storage systems
Approved Document K - Protection from falling, collision and impact
Approved Document L - Conservation of fuel and power
Approved Document M - Access to and use of buildings
Approved Document O - Overheating
Approved Document P - Electrical safety
Approved Document Q - Security in dwellings
Approved Document R - High speed electronic communications networks
Approved Document S - Infrastructure for charging electric vehicles
Approved Document T - Toilet accommodation
Approved Document 7 - Material and workmanship

Approved Document B - Fire Safety

Approved Document B has five parts:

Each part has a brief functional requirement, supported by the detailed guidance in the Approved Document B. There are frequent references throughout the Approved Document to British Standard BS 5588: ‘Fire precautions in the design, construction and use of buildings’. Designing to the relevant parts of this standard is often required or advised by the Approved Document.

B1 – Means of Escape

The purpose of this part is to ensure as far as possible that people are able to escape from a building or get to a place of safety should a fire start. There should be a sufficient number of escape routes which are protected from fire, and the requirements are laid down in the Approved Document, often with cross-reference to BS 5588.

In dwelling houses, windows are regarded as an escape route, but there are no specific requirements of the glass.

In the case of loft conversions, however, any glazing in the enclosure to the stair, including doors, should be fire resistant. The windows should be openable, and within 1.7m of the eaves (measured on the roof surface), to allow for escape. Where a window is installed for escape purposes, BS 5588: Part 1 ‘Code of practice for residential buildings’ recommends it should provide an unobstructed opening of not less than 500 x 850mm, and the bottom should not be less than 0.6m or more than 1.1m above the floor of the room. In buildings other than dwellings, escape routes must be protected by enclosures of adequate fire resistance. The performance requirements for the integrity and insulation fire resistance of elements, including glazing, are given in Table A1 of the Approved Document. However, if an integrity glass is to be used, there are limitations on its area as set down in Table A4.

For complex buildings, the Approved Document permits the use of BS 5588 or other codes relevant to the particular building type. The various parts of BS 5588 contain tables comparable with Table A4 of the Approved Document, setting area limits to the use of integrity glass.

B2 – Internal Fire Spread (linings)

Internal lining materials to a building can significantly contribute to fire growth as a result of flame spread across their surface, or by the amount of heat they release during combustion.

The Approved Document gives performance requirements for different situations. The main classifications are based on tests to BS 476: ‘Fire tests on buildings, materials and structures’ Part 6 ‘Method of test for fire propagation for products’ and Part 7 ‘Method for classification of the surface spread of flame of products’. All glass within the Pilkington range (with the exception of some cast-in-place (CIP) laminates) meet the highest performance specification of these tests, and so their use is not restricted by the requirements of Part B2.

B3 – Internal Fire Spread (structure)

This part of the Regulations is intended to ensure that fire is contained within the room or space of origin, and that the spread of smoke and fire is inhibited by fire resisting compartmentation, so that structural integrity is maintained for a reasonable period. The sizes of compartments are prescribed. The walls separating these compartments must achieve specific periods of fire resistance, and so the fire resistance performance of any glazing in such walls is crucial. Every compartment wall should comply with the minimum periods of fire resistance stipulated in Tables A1 and A2 of the Approved Document. The required periods of resistance depend upon the purpose group and height of the building, but the most onerous requirement is for 120 minutes fire resistance. Pilkington Pyrostop® in a steel screen has been tested to achieve 120 minutes integrity and insulation to BS 476: Part 22 ‘Methods for determination of the fire resistance of non-load bearing elements of construction’ (test reference WARRES 46730). The fire resistance performance of Pilkington products in a range of doors, door surrounds, screens and partitions can be seen in the summary table in the literature Fire-Resistant Glass Range. Doors in compartment walls should generally have a fire resistance performance as good as that required for the wall; detailed requirements are given in Table B1 of Appendix B to the Approved Document.

Any stairway passing from one compartment to another must be enclosed in a ‘protected shaft’, which has to achieve a specified fire resistance performance. Protected shafts may contain glazed screens, between the stair and a lobby or corridor, provided the screen achieves 30 minutes fire resistance in terms of integrity.

A glazed door which is needed to provide a means of escape may be inserted in a protected shaft, provided it has the same fire resistance as the shaft.

B4 – External Fire Spread

This part of the Regulations specifies that the external walls and roof of a building shall resist the spread of fire over their surfaces, and from one building to another. Diagram 36 in the Approved Document indicates the limitations on the use of combustible materials on external surfaces. As a non-combustible material, glass cladding is unaffected by these limitations. The Regulations also seek to limit the likelihood of fire breaking out of one building and reaching another. The concept of ‘unprotected areas’ is introduced for this purpose. Unprotected area is defined as any part of an external wall which has less fire resistance than the appropriate amount for the wall given in Table A2. Thus, windows containing ordinary annealed glass may well be defined as unprotected areas. The Regulations permit unprotected areas up to a maximum, depending on the type of building and its distance from the boundary. If the area of openings exceeds these areas, the openings must achieve the same fire resistance performance as the wall which contains them. Pilkington products for fire resistance enable this performance to be achieved. In roofs, the Approved Document lays out minimum distances of roof coverings from boundaries, depending on their performance to BS 476: Part 3: 1958 (External fire exposure roof tests). The Standard rates constructions according to two letters; the first indicates the time to penetration, the second is a measure of the spread of flame. Most glass products achieve AA, the best rating, and their unrestricted use in roof coverings is therefore acceptable.

B5 – Access and Facilities for the Fire Service

This part of the Approved Document defines the requirements which ensure adequate access to, and within, the building in order to fight fire. Requirements for the provision of fire fighting shafts are given. This part of the Approved Document makes no specific requirements relating to glazing, although it does refer to BS 5588: Part 5: 1991 ‘Code of practice for fire fighting stairs and lifts’, which makes reference to the use of glass in fire fighting stairs and lobbies.

To download the England and Wales building regulations Part B click here.

Developments in glass have resulted in the introduction of more sophisticated products with increasingly higher fire resistance performances, in both integrity (resistance to fire penetration) and insulation (resistance to the transfer of excessive heat).

Pilkington Fire Protection Glass Range:

Pilkington Pyrostop™

A clear, laminated fully insulating fire and safety glass that offers the highest levels of fire protection (integrity and insulation), maximising the available levels of natural light and visibility. The achieved classifications for integrity and insulation (EI) are for 30, 60, 90, 120 and 180 minutes.

Depending on the thickness, it provides impact safety up to Class 1 BS EN 12600.

Pilkington Pyrodur™

A clear, laminated fire resistant and safety glass primarily designed to provide integrity but also offering full insulation (against all heat transfer) for a short period. Developed specifically for use in doors and screens, it provides impact safety to Class 1 and Class 2 of BS EN 12600 (depending on thickness). It has achieved integrity classifications (E & EW) for 30 and 60 minutes, and insulation (EI) for 15 minutes.

Pilkington Pyrodur™ Plus

An advanced thin, clear fire-resistant laminate glass, which easily meets all the latest European fire and impact standards. Using a special clear intumescent interlayer, it offers an excellent combination of fire and impact to Class 2 of BS EN 12600. It has achieved integrity classification (E & EW) for 30 minutes, and insulation (EI) for 15 minutes.

Approved Document K - Impact Safety

For new buildings, and for buildings subject to major refurbishment, glazing requirements for critical locations are given in a combination of Building Regulations with supporting Approved Documents and British Standards publications.

Approved Document K became effective in England from 6th April 2013. It incorporates the former Approved Document N (Glazing - Safety in relation to impact, opening and cleaning), which is still applicable in Wales.

There are relevant British Standards:

BS EN 12600: Glass in building - Pendulum test - Impact test method and classification for flat glass
BS 6262-4: Code of practice for glazing for buildings - Part 4: Safety related to human impact
BS 6180: Barriers in and about buildings - Code of practice

In general, if the recommendations in BS 6262-4 and BS 6180 are followed, the current requirements of Building Regulations in all regional areas of the UK for the glazing of critical locations may be satisfied.

To access Approved Documents for England please click here.

Approved Document K - Stairs Ramps and Barriers

For new buildings and for buildings subject to major refurbishment, the requirements for glazing when incorporated in the designs of stairs, ramps and barriers are given in a combination of Building Regulations (with supporting Approved Documents or Technical Handbooks) and British Standards publications.

Approved Document K became effective in England from 6th April 2013. It now incorporates the former Approved Document N (Glazing - Safety in relation to impact, opening and cleaning). The six parts of Approved Document K are as follows:

K1 Stairs, ladders and ramps
K2 Protection from falling
K3 Vehicle barriers and loading bays
K4 Protection against impact with glazing
K5 Additional provisions for glazing in buildings other than dwellings
K6 Protection against impact from and trapping by doors

When glazing is used as guarding for stairs, parapets, or as balustrades it must be capable of withstanding the loadings and satisfy minimum height requirements.

Further guidance on the appropriate loads on infill panels can be obtained from BS 6180: Barriers in and about buildings - Code of practice.

Guarding should be provided where it is necessary for safety reasons to guard the edges of any floor including window, gallery, balcony, roof (including rooflights) and other openings to which people have access (unless for maintenance) such as light walls, basement areas and any sunken area next to a building.

Where buildings are likely to be used by children under 5 years old, the guarding should be designed to prevent young children becoming trapped by the guarding. A 100 mm diameter sphere must be unable to pass through any gap in the guarding. It must be designed so that children can not readily climb up it.

For access to Approved Documents, please click here.

Approved Document L - Conservation of fuel and power

Changes to Part L of the Building Regulations in England, including the supporting Approved Documents, are expected to have a significant impact on glass and glazing products in residential and non-residential buildings. High performance, energy efficient glass and windows are expected to play a crucial role in delivering nearly zero energy buildings (nZEB) in the UK.

The consultation process was undertaken in stages, beginning in late 2019 and ending on 13^th April 2021,and it is important that our industry understands the opportunities these new requirements will bring. On 15^th December 2021, the Government published the 2021 editions of the supporting Approved Documents Part L (conservation of fuel and power) and Part F (ventilation) of the Building Regulations for new and existing buildings, as well as the new regulation (Part O) addressing the risk of overheating in new homes.

The confirmed timeline for these regulatory changes are as follows:

Date	Action
From late 2019 to April 2021	Consultations completed on: Future Homes Standard Overheating in new dwellings Energy efficiency standards for work carried out in new and existing dwellings Energy efficiency standards for new buildings other than dwellings Energy efficiency standards for work to existing buildings other than dwellings
15^th December 2021	Publication of new Approved Documents Part L, F and O
15^th June 2022	Part L, F and O come into force

Hand in hand with Part L are the compliance tools such as Standard Assessment Procedure (SAP) and Simplified Building Energy Model (SBEM). Although the tools contain default values for windows, they do tend to be generic and conservative. We would encourage all designers to use manufacturers' values in these programs and real window sizes and orientations to realise the contribution that energy efficient windows can make. Our Spectrum online calculator can be used to quickly determine the g value and centre pane U value for our range of thermal insulation and solar control glass.

New Dwellings

The government recently consulted on its proposals for the Future Homes Standards and Part L 2025 in England. For our briefing on this consultation and the implications for the glass and glazing industry, please click on the link below:

Pilkington briefing on Future Homes Standard

Ahead of the introduction of the Future Home Standard in 2025, changes to the regulatory requirements for the energy efficiency of new dwellings from 2022 are expected to have an impact upon glass and glazing products.

Published on 15^th December 2021 and coming into force on 15^th June 2022, the government has set out its new requirements for Part L (conservation of fuel and power) of the Building Regulations and the supporting Approved Document for new dwellings in England.

The 2021 edition of Approved Document L Volume 1 has introduced changes to the limiting elemental standards for fabric performance – sometimes referred to as 'backstop' values – including a reduction (improvement) in the window U-value from 2.0 to 1.6 W/m²K. The new limiting U-values for fenestration elements in new dwellings are provided in the table below.

Fenestration element	Maximum U-value (W/m²K)
Windows (including roof windows and curtain walling)	1.6
Rooflights (in horizontal position)	2.2
Doors (including glazed doors)	1.6

However, the expectation is that the U-value will have to be much lower than the above to enable a new dwelling to achieve its targets for primary energy, carbon dioxide emissions and fabric energy efficiency rates. This is highlighted in the notional specification for new dwellings which includes the following reference U-values for fenestration elements:

Fenestration element	Reference U-value for target setting (W/m²K)
Opaque doors (less than 30% glazed area)	1.0
Semi-glazed doors (30 - 60% glazed area)	1.0
Windows and glazed doors with greater than 60% glazed area	1.2
Roof windows	1.2
Rooflights (in horizontal position)	1.7

Pilkington UK manufactures a range of low emissivity glass for thermal insulation that can help windows and doors to achieve low U-values.

The 2021 editions of Approved Document L Volumes 1 and 2 can be downloaded from here.

Existing Dwellings

Changes to the Building Regulations for existing dwellings in England are expected to have an impact upon glass and glazing products in residential buildings.

Published on 15^th December 2021 and coming into force on 15^th June 2022, the government has set out its new requirements for Part L (conservation of fuel and power) of the Building Regulations and the supporting Approved Document for existing dwellings in England.

The 2021 edition of Approved Document L Volume 1 has made changes to the standards for fabric performance of building elements in existing dwellings. For replacement windows, doors and rooflights in existing dwellings, the following standards have been introduced:

Fabric element	Maximum U-value (W/m²K)
Window (including roof window or curtain walling)	1.4 or minimum WER Band B
Rooflight	2.2
Doors with greater than 60% on internal face glazed	1.4 or minimum Door Set Energy Rating (DSER) Band C
Other doors	1.4 or minimum Door Set Energy Rating (DSER) Band B

For timber windows, a maximum U-value of 1.6 W/m²K or WER band C is permissible until 14^th June 2023. From 15^th June 2023, the full standard of a maximum U-value of 1.4 W/m²K or WER band B applies.

For timber doors, a maximum U-value of 1.8 W/m²K or DSER band E is permissible until 14^th June 2023. From 15^th June 2023, the full standard of a maximum U-value of 1.4 W/m²K or WER band C / B applies.

For external fire doorsets, a maximum U-value of 1.8 W/m²K is permissible.

WER, Window Energy Rating, is generally considered a better indicator of the energy performance of a window because it considers a range of parameters, including the useful solar heat gain. The U-value is the total U-value of the window, taking into account both the glass and frame.

The U-value of a rooflight should be based on the outer developed surface area, which is often greater than the area of the roof opening.

The proposals include an alternative if windows or fully glazed external pedestrian doors cannot meet the above requirements because of the need to maintain the character of the building. In such cases, they should achieve or better a centre pane U value of 1.2 W/m²K or be upgraded to low emissivity (low-e) secondary glazing.

The 2021 editions of Approved Document L Volumes 1 and 2 can be downloaded from here.

Conservatories

Changes to the Building Regulations for new and existing dwellings in England are expected to have an impact upon glass and glazing products, but they do not affect conservatories.

Published on 15^th December 2021 and coming into force on 15^th June 2022, the government has set out its new requirements for Part L (conservation of fuel and power) of the Building Regulations and the supporting Approved Document for dwellings in England.

The 2021 edition of Approved Document L Volume 1 has not introduced any changes regarding conservatories. They remain exempt from energy efficiency requirements, provided:

the conservatory is at ground floor level
the floor area does not exceed 30m²
glazing complies with Part K of the Building Regulations (e.g. safety)
any wall, door or window separating the conservatory from the rest of dwelling has been retained or replaced with a wall, door or window, and
the heating system of the dwelling is not extended into the conservatory nor does the conservatory have its own fixed heating appliance

Note that any replacement walls, doors and windows should satisfy energy efficiency requirements for those elements.

Despite the above, a conservatory can benefit from incorporating solar control and low emissivity glass to help maintain a comfortable environment all-year round. Pilkington manufactures a range of products, including combined solar control and self-cleaning glass, for use in conservatory applications.

The 2021 editions of Approved Document L Volumes 1 and 2 can be downloaded from here

New Non-dwellings

Ahead of the introduction of the Future Building Standard in 2025, changes to the regulatory requirements for the energy efficiency of new buildings other than dwellings are expected to have an impact upon glass and glazing products.

Published on 15^th December 2021 and coming into force on 15^th June 2022, the government has set out its new requirements for Part L (conservation of fuel and power) of the Building Regulations and the supporting Approved Document for new non-dwellings in England.

There are no specific values for individual building elements, but a new building must be shown to meet or better the target primary energy and carbon dioxide emission rates for a notional building of the same size and shape as an actual building with standardised properties for fabric and services.

The 2021 edition of Approved Document L Volume 2 has made changes to the limiting elemental standards for fabric performance – sometimes referred to as 'backstop' values – including a reduction (improvement) in the window U-value from 2.2 to 1.6 W/m²K. The new limiting U-values for fenestration elements in new buildings other than dwellings are provided in the table below.

Element	Maximum U-value (W/m²K)
Windows in buildings similar to dwellings*	1.6 or minimum WER Band B
All other windows, roof windows and curtain walling	1.6
Rooflights	2.2
Pedestrian doors (including glazed doors)	1.6

*for example, student accommodation and care homes

For external fire doorsets, a maximum U-value of 1.8 W/m²K is permissible.

The U-value of a rooflight should be based on the outer developed surface area, which is often greater than the area of the roof opening. Unlike for windows and roof windows, rooflights should have their U-values calculated based on a horizontal position.

No maximum U-value has been set for display windows and similar glazing. However, the impact of display windows must be taken into account in the calculation of primary energy and CO₂ emissions for the new building.

The 2021 editions of Approved Document L Volumes 1 and 2 can be downloaded from here.

Existing Non-dwellings

Changes to the regulatory requirements for the energy efficiency of existing buildings other than dwellings are expected to have an impact upon glass and glazing products.

Published on 15^th December 2021 and coming into force on 15^th June 2022, the government has set out its new requirements for Part L (conservation of fuel and power) of the Building Regulations and the supporting Approved Document for existing non-dwellings in England.

The 2021 edition of Approved Document L Volume 2 has made changes to the fabric performance of replacement elements in existing buildings, including a reduction (improvement) in the window U-value.

The table below summarises the maximum U-values for new elements in extensions to existing buildings other than dwellings and new or replacement elements in existing buildings other than dwellings:

Element	Maximum U-value (W/m²K)
Windows in buildings similar to dwellings*	1.6 or minimum WER Band B
All other windows, roof windows and curtain walling	1.6
Rooflights	2.2
Pedestrian doors (including glazed doors)	1.6

*for example, student accommodation and care homes

WER, Window Energy Rating, is generally considered a better indicator of the energy performance of a window in an existing dwelling or similar building because it considers a range of parameters, including the useful solar heat gain. The U-value is the total U-value of the window, taking into account both the glass and frame.

The U-value of a rooflight should be based on the outer developed surface area, which is often greater than the area of the roof opening. Unlike for windows and roof windows, rooflights should have their U-values calculated based on a horizontal position.

No maximum U-value has been set for display windows and similar glazing for existing buildings.

Approved Document L Volume 2 also includes an alternative if windows or fully glazed external pedestrian doors cannot meet the above requirements because of the need to maintain the character of the existing building. In such cases, they should achieve or better a centre pane U-value of 1.2 W/m²K or be upgraded to low emissivity (low-e) secondary glazing.

The 2021 editions of Approved Document L Volumes 1 and 2 can be downloaded from here.

Approved Document O - Overheating

A new Building Regulation for overheating in new dwellings in England is expected to have a significant impact on glass and glazing products in residential buildings.

Published on 15^th December 2021 and coming into force on 15^th June 2022, the government has set out its new requirements for Part O (overheating) of the Building Regulations and the supporting Approved Document for new dwellings in England.

Applying only to new residential buildings, new residential buildings must be designed and constructed in such a way as to limit unwanted solar gains in summer and provide an adequate means to remove excess heat from inside. Two methods of assessment are given in Approved Document O:

Simplified method, related to location, dwelling type, glazing area and presence of cross-ventilation
Detailed thermal analysis method, involving calculation of the risk of overheating

For the simplified method, England is split into two:

Moderate risk locations (England excluding higher risk parts of London
High risk locations (urban and some suburban parts of London)

As buildings located in some Central Manchester postcodes may also experience elevated night-time temperatures, they should be considered high risk.

Using the simplified method, new residential buildings should meet the maximum glazing area and shading standards in the tables below.

Limiting solar gains for buildings with cross-ventilation

Largest glazed façade orientation	High risk location		Moderate risk location
Largest glazed façade orientation	Maximum area of glazing (% floor area)	Maximum area of glazing in most glazed room (% floor area of room)	Maximum area of glazing (% floor area)	Maximum area of glazing in most glazed room (% floor area of room)
North	15	37	18	37
East	18	37	18	37
South	15	22	15	30
West	18	37	11	22

Limiting solar gains for buildings without cross-ventilation

Largest glazed façade orientation	High risk location		Moderate risk location
Largest glazed façade orientation	Maximum area of glazing (% floor area)	Maximum area of glazing in most glazed room (% floor area of room)	Maximum area of glazing (% floor area)	Maximum area of glazing in most glazed room (% floor area of room)
North	15	26	18	26
East	11	18	18	26
South	11	11	15	15
West	11	18	11	11

Cross-ventilation is defined as the ability to ventilate using openings on opposite facades of a dwelling. Having openings on facades that are not opposite is not allowing cross-ventilation, e.g. in a corner flat.

In addition to the above, residential buildings in high risk locations should also provide shading to glazed areas between compass points north-east and north-west via the south. Where shading is required, glazing with a maximum g value of 0.40 and a high light transmittance of 0.70 can be used.

In terms of removing excess heat, the proposals set a minimum free area (geometric open area of a ventilator) dependent upon floor and glazing areas and whether the building has cross-ventilation.

If using the dynamic thermal analysis method to predict overheating risk, the methodology set out in CIBSE TM59 'Design methodology for the assessment of overheating risk in homes' should be followed.

The 2021 edition of Approved Document O can be downloaded from here.

Approved Document Q - Security

Effective since 1st October 2015, Approved Document Q (England) sets security requirements for new dwellings in England. The approved document sets out reasonable standards for doors and windows to resist physical attack by a casual or opportunist burglar by being both sufficiently robust and fitted with appropriate hardware.

To meet the requirement, reasonable provision must be made to resist unauthorised access to any dwelling and any part of a building from which access can be gained to a flat within a building.

Ground floor, basement and other easily accessible windows (including easily accessible rooflights) need to be secure windows. A window that has been shown by test to meet the security requirements of PAS 24 would be considered a secure window.

According to PAS 24, where doorsets, coupled side panels and windows adjacent to doorsets contain glass, each glazed area shall include at least one pane of laminated glass meeting the requirements of BS EN 356:2000, Class P1A or higher.

Where windows contain glass and non-key unlocking hardware, each glazed area shall include at least one pane of laminated glass meeting the requirements of BS EN 356:2000, Class P1A or higher, and shall be glazed in accordance with BS 6262.

6.8 mm Pilkington Optilam™ achieves BS EN 356 Class P2A (which is higher than P1A), so would satisfy this requirement. Please note that 6.4 mm Pilkington Optilam™ does not achieve Class P1A.

The requirement does not apply to replacement windows and doors.

To read Approved Document Q in full, please click here.

Wales

Practical guidance on how to comply with the Building Regulations in Wales is provided within Approved Documents. Each document contains:

guidance on the performance expected of materials and building work to comply with the Building Regulations
examples and solutions on how to achieve compliance for some building situations.

There is no obligation to adopt a particular solution contained within the Approved Documents. Re-designed Approved Documents for Wales have replaced those issued by HM Government and took effect from 3rd April 2017.

The Approved Documents for Wales can be accessed here.

These are the Approved Documents for Wales:

Approved Document A: Structural safety
Approved Document B: Fire safety
Approved Document C: Resistance to contaminants and moisture
Approved Document D: Toxic substances
Approved Document E: Resistance to sound
Approved Document F: Ventilation
Approved Document G: Sanitation, hot water safety and water efficiency
Approved Document H: Drainage and waste disposal
Approved Document J: Heat producing appliances
Approved Document K: Protection from falling
Approved Document L: Conservation of fuel and power
Approved Document M: Access to and use of buildings
Approved Document N: Glazing safety
Approved Document P: Electrical safety
Approved Document Q: Security
Approved Document R: Physical Infrastructure for high-speed electronic communications networks
Approved Document 7: Workmanship and materials

Approved Document B - Fire Safety

Compliance with the minimum standards of fire safety laid down in Building Regulations is crucial in achieving buildings which provide adequate protection for life and property in the event of fire.

The content of the Regulations, the frequency and timing of revisions and the regulatory regimes differ between England and Wales, Scotland and Northern Ireland. However, in each country’s Regulations, glass performs a vital role in achieving the requirements for fire protection.

The relevant part of the Building Regulations is Part B – Fire Safety. There are five parts:

B1 – Means of Escape

The purpose of this part is to ensure as far as possible that people are able to escape from a building or get to a place of safety should a fire start. There should be a sufficient number of escape routes which are protected from fire, and the requirements are laid down in the Approved Document, often with cross-reference to BS 5588.

In dwelling houses, windows are regarded as an escape route, but there are no specific requirements of the glass.

In the case of loft conversions, however, any glazing in the enclosure to the stair, including doors, should be fire resistant. The windows should be openable, and within 1.7m of the eaves (measured on the roof surface), to allow for escape. Where a window is installed for escape purposes, BS 5588: Part 1 ‘Code of practice for residential buildings’ recommends it should provide an unobstructed opening of not less than 500 x 850mm, and the bottom should not be less than 0.6m or more than 1.1m above the floor of the room. In buildings other than dwellings, escape routes must be protected by enclosures of adequate fire resistance. The performance requirements for the integrity and insulation fire resistance of elements, including glazing, are given in Table A1 of the Approved Document. However, if an integrity glass is to be used, there are limitations on its area as set down in Table A4.

For complex buildings, the Approved Document permits the use of BS 5588 or other codes relevant to the particular building type. The various parts of BS 5588 contain tables comparable with Table A4 of the Approved Document, setting area limits to the use of integrity glass.

B2 – Internal Fire Spread (linings)

Internal lining materials to a building can significantly contribute to fire growth as a result of flame spread across their surface, or by the amount of heat they release during combustion.

The Approved Document gives performance requirements for different situations. The main classifications are based on tests to BS 476: ‘Fire tests on buildings, materials and structures’ Part 6 ‘Method of test for fire propagation for products’ and Part 7 ‘Method for classification of the surface spread of flame of products’. All glass within the Pilkington range (with the exception of some cast-in-place (CIP) laminates) meet the highest performance specification of these tests, and so their use is not restricted by the requirements of Part B2.

B3 – Internal Fire Spread (structure)

This part of the Regulations is intended to ensure that fire is contained within the room or space of origin, and that the spread of smoke and fire is inhibited by fire resisting compartmentation, so that structural integrity is maintained for a reasonable period. The sizes of compartments are prescribed. The walls separating these compartments must achieve specific periods of fire resistance, and so the fire resistance performance of any glazing in such walls is crucial. Every compartment wall should comply with the minimum periods of fire resistance stipulated in Tables A1 and A2 of the Approved Document. The required periods of resistance depend upon the purpose group and height of the building, but the most onerous requirement is for 120 minutes fire resistance. Pilkington Pyrostop® in a steel screen has been tested to achieve 120 minutes integrity and insulation to BS 476: Part 22 ‘Methods for determination of the fire resistance of non-load bearing elements of construction’ (test reference WARRES 46730). Doors in compartment walls should generally have a fire resistance performance as good as that required for the wall; detailed requirements are given in Table B1 of Appendix B to the Approved Document.

Any stairway passing from one compartment to another must be enclosed in a ‘protected shaft’, which has to achieve a specified fire resistance performance. Protected shafts may contain glazed screens, between the stair and a lobby or corridor, provided the screen achieves 30 minutes fire resistance in terms of integrity.

A glazed door which is needed to provide a means of escape may be inserted in a protected shaft, provided it has the same fire resistance as the shaft.

B4 – External Fire Spread

This part of the Regulations specifies that the external walls and roof of a building shall resist the spread of fire over their surfaces, and from one building to another. Diagram 36 in the Approved Document indicates the limitations on the use of combustible materials on external surfaces. As a non-combustible material, glass cladding is unaffected by these limitations. The Regulations also seek to limit the likelihood of fire breaking out of one building and reaching another. The concept of ‘unprotected areas’ is introduced for this purpose. Unprotected area is defined as any part of an external wall which has less fire resistance than the appropriate amount for the wall given in Table A2. Thus, windows containing ordinary annealed glass may well be defined as unprotected areas. The Regulations permit unprotected areas up to a maximum, depending on the type of building and its distance from the boundary. If the area of openings exceeds these areas, the openings must achieve the same fire resistance performance as the wall which contains them. Pilkington products for fire resistance enable this performance to be achieved. In roofs, the Approved Document lays out minimum distances of roof coverings from boundaries, depending on their performance to BS 476: Part 3: 1958 (External fire exposure roof tests). The Standard rates constructions according to two letters; the first indicates the time to penetration, the second is a measure of the spread of flame. Most glass products achieve AA, the best rating, and their unrestricted use in roof coverings is therefore acceptable.

B5 – Access and Facilities for the Fire Service

This part of the Approved Document defines the requirements which ensure adequate access to, and within, the building in order to fight fire. Requirements for the provision of fire fighting shafts are given. This part of the Approved Document makes no specific requirements relating to glazing, although it does refer to BS 5588: Part 5: 1991 ‘Code of practice for fire fighting stairs and lifts’, which makes reference to the use of glass in fire fighting stairs and lobbies.

To download the England and Wales building regulations Part B click here.

Pilkington Fire Protection Glass Range:

Pilkington Pyrostop™

Depending on the thickness, it provides impact safety up to Class 1 BS EN 12600.

Pilkington Pyrodur™

Pilkington Pyrodur™ Plus

Approved Document K - Impact Safety

For new buildings, and for buildings subject to major refurbishment, glazing requirements for critical locations are given in a combination of Building Regulations (with supporting Approved Documents or Technical Handbooks) and British Standards publications.

Approved Document K became effective in England from 6th April 2013. It now incorporates the former Approved Document N (Glazing - Safety in relation to impact, opening and cleaning), which is still applicable in Wales.

There are relevant British Standards:

BS EN 12600: Glass in building - Pendulum test - Impact test method and classification for flat glass
BS 6262-4: Code of practice for glazing for buildings - Part 4: Safety related to human impact
BS 6180: Barriers in and about buildings - Code of practice

In general, if the recommendations in BS 6262-4 and BS 6180 are followed, the current requirements of Building Regulations in all parts of the UK for the glazing of critical locations may be satisfied.

To access Approved Documents for Wales please click here.

Approved Document K - Stairs Ramps and Barriers

K1 Stairs, ladders and ramps
K2 Protection from falling
K3 Vehicle barriers and loading bays
K4 Protection against impact with glazing
K5 Additional provisions for glazing in buildings other than dwellings
K6 Protection against impact from and trapping by doors

When glazing is used as guarding for stairs, parapets or as balustrades it must be capable of withstanding the loadings and satisfy minimum height requirements.

Further guidance on the appropriate loads on infill panels can be obtained from BS 6180: Barriers in and about buildings - Code of practice.

Guarding should be provided where it is necessary for safety reasons to guard the edges of any floor including window, gallery, balcony, roof (including rooflights) and other openings to which people have access (unless for maintenance) such as light walls, basement areas and any sunken area next to a building.

Where buildings are likely to be used by children under 5 years old, the guarding should be designed to prevent young children becoming trapped by the guarding. A 100mm diameter sphere must be unable to pass through any gap in the guarding. It must be designed so that children can not readily climb up it.

For access to Approved Documents, please click here.

Approved Document L - Conservation of Fuel and Power

New Dwellings

On 24th May 2022, the Welsh government issued new and updated Approved Documents in support of the Building Regulations for residential buildings in Wales. These changes are expected to have a significant impact on glass and glazing products in new and existing dwellings.

Taking effect on 23rd November 2022, the new Approved Document L Volume 1 Dwellings (conservation of fuel and power) includes provisions to reduce the carbon emissions and improve the energy performance of new dwellings in Wales.

The changes to the worst acceptable fabric performance values – sometimes referred to as 'backstop' values - include reducing (improving) the window U value from 1.6 to 1.4 W/m²K. For windows, doors and rooflights in new dwellings, the new 'backstop' values are given in Table 1.

Table 1 - Worst acceptable fabric performance values in new dwellings

Element	Maximum U value (W/m²K)
Windows or roof windows	1.4
Rooflight (horizontal position)	2.2
Doors	1.4

The expectation is that the U values will have to be lower than those given in Table 1 to enable new dwellings to achieve the whole building minimum energy performance target. This is highlighted in the elemental specification for the notional dwelling summarised in Table 2.

Table 2 - Elemental specification for the notional dwelling

Element	Maximum U value (W/m²K)
Windows, roof windows and glazed doors	1.3
Rooflights (horizontal position)	1.6
Opaque and semi-glazed doors	1.0

To satisfy the above requirements, Pilkington provides a range of low-e glass that can provide thermal insulation.

To access the new Approved Documents on the Welsh government's website, please click here.

Existing dwellings in Wales

On 24^th May 2022, the Welsh government issued new and updated Approved Documents in support of the Building Regulations for residential buildings in Wales. These changes are expected to have a significant impact on glass and glazing products in new and existing dwellings.

Taking effect on 23^rd November 2022, the new Approved Document L Volume 1 Dwellings (conservation of fuel and power) includes provisions to improve the energy performance of existing dwellings in Wales. For replacement windows, doors and rooflights in existing dwellings, the following standards have been set:

Element	Standard
Window or roof window	Maximum U value 1.4 W/m²K or minimum Window Energy Rating (WER) band B
Rooflights (horizontal position)	Maximum U value 2.2 W/m²K
Doors (>60% internal face glazed)	Maximum U value of 1.4 W/m²K or minimum Doorset Energy Rating (DER) band C
All other doors	Maximum U value of 1.4 W/m²K or Minimum Doorset Energy Rating (DER) band B

WER, Window Energy Rating, is generally considered a better indicator of the energy performance of a window because it considers a range of parameters, including the useful solar heat gain. The U value is the total U value of the window, taking into account both the glass and frame.

There is an alternative approach in the case of dwellings of architectural and historical interest where special considerations apply or there is a need to maintain the character of a façade. If the windows or doors are unable to achieve the above U values in such dwellings, they should achieve or better a centre pane U value of 1.2 W/m²K or be upgraded to low emissivity (low-e) secondary glazing.

For timber windows, a maximum U value of 1.6 W/m²K or Window Energy Rating band C is permissible before 23^rd November 2023 to allow manufacturers additional time to transition to full standard of 1.4 W/m²K or WER band B. For timber doors, a maximum U value of 1.8 W/m²K is permissible before 23^rd November 2023 to allow manufacturers additional time to transition to full standard of 1.4 W/m²K.

To satisfy the above requirements, Pilkington provides a range of low-e glass that can provide thermal insulation.

To access the new Approved Documents on the Welsh government's website, please click here.

If you have any questions on Part L 2021 in Wales and what the implications might be for glass, please complete our online contact form, selecting 'Architect' or 'Trade' as the Nature of Enquiry and 'Part L' as the Enquiry Type.

Buildings other than dwellings

On 26^th September 2022, the Welsh government issued new and updated Approved Documents in support of the Building Regulations for non-residential buildings in Wales. These changes are expected to have a significant impact on glass and glazing products in new and existing buildings.

Taking effect on 29^th March 2023, the new Approved Document L Volume 2 buildings other than dwellings (conservation of fuel and power) includes provisions to reduce the carbon emissions and improve the energy performance of new non-residential buildings in Wales.

Although new buildings are required to achieve a Target Primary Energy Rate and Target Emission Rate, limiting U values – sometimes referred to as 'back stop' U values – are set for some building elements to prevent poor fabric design. The following limiting U values for fenestration elements have been set for new non-domestic buildings:

Element	Maximum U value (W/m²K)
Windows	1.6
Roof windows, curtain walling	1.8
Rooflights	2.2
Pedestrian doors (including glazed doors)	1.8

Dependent upon the project design, the U values may have to be lower than the above values to enable new buildings to achieve the target rates for the building.

Limiting U values for new and replacement fenestration elements in existing non-domestic buildings are provided in the table below:

Element	Maximum U value (W/m²K)
Element	Buildings essentially domestic in character	All other buildings
Windows	1.4 or Window Energy Rating band B	1.8
Roof windows, curtain walling	1.8	1.8
Rooflights	2.2	2.2
Pedestrian doors (including glazed doors)	1.8	1.8

If windows or fully glazed pedestrian doors are unable to meet the above requirements in an existing building, in order to maintain the character of the building, either of the following should apply:

the maximum centre pane U value should be 1.2 W/m²K, or
single glazing should be supplemented with low emissivity secondary glazing

Provisions also need to be made to limit heat gains in the summer. For each space in the building that is occupied or mechanically cooled, solar gains through the glazing – aggregated from April to September inclusive - should be no greater than would occur through the relevant reference glazing systems.

For transitional arrangements, the new requirements do not apply to work on a particular building where a building notice, full plans application or initial notice have been submitted before that date, provided the work for each building is started before 29^th March 2024.

The new Approved Document L Volume 2 for buildings in Wales other than dwellings can be found here.

Approved Document O - Overheating

On 24^th May 2022, the Welsh government issued new and updated Approved Documents in support of the Building Regulations for residential buildings in Wales. These changes are expected to have a significant impact on glass and glazing products in new and existing dwellings.

Taking effect on 23^rdNovember 2022, the new Approved Document O introduces requirements to mitigate the risk of overheating in new dwellings in Wales.

Applying only to new dwellings, Approved Document O requires dwellings to be designed and constructed in such a way as to provide reasonable mitigation from the risk of summertime overheating. In addition, any mitigation measures would need to be safe, secure and reasonably practical for occupants. Two methods of assessment are provided:

Simplified method, related to glazing and floor areas
Detailed thermal analysis method, involving calculation of the risk of overheating

The simplified method involves adopting one of several mitigation approaches to limit solar gains and an approach for heat removal from the dwelling (see Table 1 below).

Table 1 - Controlling overheating by minimising summer solar gains and heat removal

Mitigating approach	Minimising summer solar gains	Heat removal (openable windows and ventilation louvres)
Single aspect residential buildings
S1	Maximum glazed area of 15% of floor area	Minimum free area of 12% of floor area
S2	Maximum glazed area of 20% of floor area Glazing with maximum g value of 0.40	Minimum free area of 10% of floor area
Dual aspect residential buildings
D1	Maximum glazed area of 15% of floor area	Minimum free area of 12% of floor area
D2	Maximum glazed area of 35% of floor area Glazing with maximum g value of 0.40	Minimum free area of 12% of floor area
D3	Maximum glazing area of 35% of floor area. External shutters with means of ventilation on all facades. Overhangs with 50^o altitude cut-off can be used instead of external shutters on South facades (i.e. walls with South East to South West facing orientation)	Minimum free area of 12% of floor area

The glazing area in Table 1 should be calculated as the net glazing area, excluding the window frame. When selecting the preferred approach from Table 1, the ability to deliver adequate daylighting and maximise winter solar gains should be considered. Glazed areas should be distributed across all facades to ensure adequate daylight levels.

The proposed Approved Document defines a single aspect dwelling as one that has windows in one direction only, whereas a dual aspect dwelling has windows facing two or more directions.

To satisfy the above requirements, Pilkington provides a range of solar control glass that can provide solar control and / or thermal insulation. These include products that can meet the low g value glazing requirement of a maximum 0.40 as stated in mitigation approach 2 in Table 1 above.

If using the dynamic thermal analysis method to predict overheating risk, the methodology set out in CIBSE TM59 'Design methodology for the assessment of overheating risk in homes' should be followed.

To access the new Approved Documents on the Welsh government's website, please click here.

Approved Document Q - Security

Following the publication of Approved Document Q in Wales, security is incorporated into the building regulations in Wales for the first time.

Effective since 1st November 2018, Approved Document Q (Wales) sets security requirements for new dwellings in England. The approved document sets out reasonable standards for doors and windows to resist physical attack by a casual or opportunist burglar by being both sufficiently robust and fitted with appropriate hardware.

To meet the requirement, reasonable provision must be made to resist unauthorised access to any dwelling and any part of a building from which access can be gained to a flat within a building.

Ground floor, basement and other easily accessible windows (including easily accessible rooflights) need to be secure windows. A window that has been shown by test to meet the security requirements of PAS 24 would be considered a secure window.

According to PAS 24, where doorsets, coupled side panels and windows adjacent to doorsets contain glass, each glazed area shall include at least one pane of laminated glass meeting the requirements of BS EN 356:2000, Class P1A or higher.

Where windows contain glass and non-key unlocking hardware, each glazed area shall include at least one pane of laminated glass meeting the requirements of BS EN 356:2000, Class P1A or higher.

Specifically for bespoke timber doorsets, any glazing which, if broken, would permit someone to insert their hand and release the locking device on the inside of the door should be a minimum of Class P1A in accordance with BS EN 356. Insulting glass units need to incorporate only one pane of Class P1A glass.

6.8 mm Pilkington Optilam™ achieves BS EN 356 Class P2A (which is higher than P1A), so would satisfy this requirement. Please note that 6.4 mm Pilkington Optilam™ does not achieve Class P1A.

The requirement does not apply to replacement windows and doors.

To read Approved Document Q in full, please click here.

Scotland

In Scotland, Ministers are responsible for creating Building Regulations and preparing technical guidance to ensure buildings are safe, efficient and sustainable for all.

Local authorities administer the Building Standards system and are responsible for granting permission for work to be done (Building Warrant) and for a completed building to be occupied (Completion Certificate).

Technical Handbooks provide guidance on achieving the standards set in the building regulations and are available in two volumes, one for domestic buildings and the other for non-domestic buildings.

The Technical Handbooks are split into the following sections and can be accessed here.

Section 0 - General
Section 1 - Structure
Section 2 - Fire
Section 3 - Environment
Section 4 - Safety
Section 5 - Noise
Section 6 - Energy
Section 7 - Sustainability

Section 2 - Fire Safety

Pilkington Fire Protection Glass Range:

Pilkington Pyrostop™

Depending on the thickness, it provides impact safety up to Class 1 BS EN 12600.

Pilkington Pyrodur™

Pilkington Pyrodur™ Plus

Section 3 - Overheating

Effective from 1^stFebruary 2023 (deferred from 1^stDecember 2022), the Scottish Government has introduced changes to Sections 3 (environment), 6 (energy) and 7 (sustainability) of the Building Standards Technical Handbooks for domestic and non-domestic buildings.

For new dwellings, a new Section 3.28 introduces a new mandatory standard to assess and mitigate the summertime overheating risk.

Applying only to new residential buildings, the new standard requires dwellings to be designed and constructed in such a way as to limit solar gains through glazing and provide ventilation to assist in effective cooling. Two methods of assessment are provided:

Simple method, specifying measures to mitigate risk of summer overheating
Detailed thermal analysis modelling, involving calculation of the risk of overheating

Using the simple method, for new residential buildings with a glazed area greater than 20% of the room floor area, shading (e.g. louvres, external shutters, etc.) should be provided. Alternatively, the glazing g value should be revised to reduce solar gain in proportion to the increase in glazed area above 20%. The latter should be based on heat gain no greater than an unshaded opening, 20% of the room floor area and a g value of 0.60. If the glazed area is doubled, then the g value should be halved.

Changes to the glass specification to reduce the g value should, where practicable, maintain a high light transmittance to minimise the adverse impact on daylighting. A light transmittance of 0.70 or higher is recommended..

By implication, glazed areas of 20% or lower would not require shading or glazing with lower g value than 0.60 when using the simple method.

To satisfy the above requirements, Pilkington offers a range of glass that can provide solar control and / or thermal insulation. This includes products that can achieve g values of 0.60 or lower, as stated in the simple method.

If using dynamic thermal analysis modelling to predict overheating risk, the methodology set out in CIBSE TM59 'Design methodology for the assessment of overheating risk in homes' should be followed. This approach may be useful for conversions, more complex dwellings and those where significant areas of glazing are proposed.

More details can be found in the new Technical Handbooks which can be found here.

Section 4 - Impact Safety

For new buildings, and for buildings subject to major refurbishment, glazing requirements for critical locations are given in a combination of Building Regulations and British Standards publications.

The relevant supporting documents for Scotland are the Technical Handbooks for domestic and non-domestic, section 4 (Safety).

There are two relevant British Standards:

BS EN 12600 ‘Glass in building - Pendulum test - Impact test method and classification for flat glass’
BS 6262: ‘Code of practice for glazing for buildings’ Part 4 ‘Safety related to human impact’

Section 4 - Security

Following the publication of Approved Document Q in England, security is incorporated into the building regulations in England for the first time.

Effective since 1st October 2015, Approved Document Q (England) sets security requirements for new dwellings in England. The approved document sets out reasonable standards for doors and windows to resist physical attack by a casual or opportunist burglar by being both sufficiently robust and fitted with appropriate hardware.

To meet the requirement, reasonable provision must be made to resist unauthorised access to any dwelling and any part of a building from which access can be gained to a flat within a building.

Ground floor, basement and other easily accessible windows (including easily accessible rooflights) need to be secure windows. A window that has been shown by test to meet the security requirements of PAS 24 would be considered a secure window.

According to PAS 24, where doorsets, coupled side panels and windows adjacent to doorsets contain glass, each glazed area shall include at least one pane of laminated glass meeting the requirements of BS EN 356:2000, Class P1A or higher.

Where windows contain glass and non-key unlocking hardware, each glazed area shall include at least one pane of laminated glass meeting the requirements of BS EN 356:2000, Class P1A or higher, and shall be glazed in accordance with BS 6262.

6.8mm Pilkington Optilam™ achieves BS EN 356 Class P2A (which is higher than P1A), so would satisfy this requirement. Please note that 6.4mm Pilkington Optilam™ does not achieve Class P1A.

The requirement does not apply to replacement windows and doors.

For more information on glass for security applications, please click HERE.

To read approved document Q in full, please click HERE.

Section 4 - Stairs Ramps and Barriers

For new buildings and for buildings subject to major refurbishment, the requirements for glazing when incorporated in the designs of stairs, ramps and barriers can be found in the regional Building Regulation Documents.

Scotland

The Building Standards (Scotland) Regulations 1990 Part S Stairs, Ramps and Protective Barriers.

The 1990 Technical Standards document provides guidance on the interpretation of the requirements.

Section 6 - Energy

Effective from 1^st February 2023 (deferred from 1^stDecember 2022), the Scottish Government has introduced changes to Sections 3 (environment), 6 (energy) and 7 (sustainability) of the Building Standards Technical Handbooks for domestic and non-domestic buildings.

These changes form part of the output from the Building Standards Energy Review Panel and measures proposed within the 2021 consultation on energy standards.

Section 6 on energy has been revised to introduce a delivered energy target for new buildings and an amendment to the notional building specifications to set compliance targets. The area-weighted average U values for fabric elements have been improved and one set of values now apply to all buildings.

Our Spectrum online calculator can be used to quickly determine the g value and centre pane U value for our range of thermal insulation and solar control glass.

New and existing domestic buildings

The Scottish Government has published changes to Section 6 (Energy) of the Technical Handbooks for domestic and non-domestic buildings to take effect on 1^st February 2023 (deferred from 1^st December 2022).

Changes in Section 6 on energy are intended to deliver 32% aggregate reduction in CO₂ emissions on 2015 standards for domestic buildings. A dwelling must achieve the overall Target Dwelling Emissions Rate and Target Dwelling Delivered Energy Rating.

For new domestic buildings, there are changes to the maximum (limiting) U values for fabric elements. However, the expectation is that the U value will have to be lower than this to enable new dwellings to achieve the overall targets. The notional dwelling specification used to determine the overall targets is based on the following U values of fenestration elements:

Fenestration element	Specification (W/m²K)
Doors	1.2
Windows	1.2
Roof Windows	1.2
Rooflights (in horizontal position)	1.7

The maximum U values for fenestration elements of dwellings (including extensions and existing dwellings) are summarised below:

Fenestration element	Maximum U value (W/m²K)
Windows and doors	1.4 or Window Energy Rating (WER) or Doorset Energy Rating (DER) minimum band B
Rooflights (in horizontal position)	2.1

The above values are for new and existing dwellings, with the exception that WER / DER apply only to existing dwellings (e.g. replacement windows and doors).

Where replacement work relates only to one or two replacement windows or doors, to allow matching windows or doors to be installed, the frame may be disregarded for assessment purposes provided the centre pane U value for each glazed unit is 1.2 W/m²K.

For secondary glazing, an existing window, after alteration should achieve a U value of about 3.5 W/m²K.

Pilkington manufactures a range of low emissivity glass for thermal insulation that can help windows and doors to achieve low U-values.

The 2022 editions of the Technical Handbooks can be found here.

If you have any questions on changes and what the implications might be for glass, please complete our online contact form, selecting 'Architect' or 'Trade' as the Nature of Enquiry and 'Other' as the Enquiry Type.
Please state 'Technical Handbook Section 6' in the Question / Comment box when completing the form.

New and existing non-domestic buildings

The Scottish Government has published changes to Section 6 (Energy) of the Technical Handbooks for domestic and non-domestic buildings to take effect on 1^st February 2023 (deferred from 1^stDecember 2022).

Changes in Section 6 on energy are intended to deliver 20% aggregate reduction in CO₂ emissions on 2015 standards for non-domestic buildings. A dwelling must achieve the overall Target Building Emissions Rate and Target Building Delivered Energy Rating.

For new non-domestic buildings, there are changes to the maximum (limiting) U values for fabric elements. However, the expectation is that the U value will have to be lower than this to enable new buildings to achieve the overall targets. The notional building specification used to determine the overall targets is based on the following U values of fenestration elements:

Fenestration element	Specification (W/m²K)
Windows and pedestrian doors	1.2 (10% frame factor) g value 50% light transmittance 77%
Rooflights (in horizontal position)	1.9 (15% frame factor) g value 52% LT 57%

The maximum U values for fenestration elements of buildings (including extensions and existing buildings) are summarised below:

Fenestration element	Maximum U value (W/m²K)
Windows and roof windows	1.6 or Window Energy Rating (WER) or Doorset Energy Rating (DER) minimum band B
Rooflights (in horizontal position)	2.2
Pedestrian doors	1.4

The above values are for new and existing building, with the exception that WER / DER apply only to existing buildings (e.g. replacement windows and doors).

Where replacement work relates only to one or two replacement windows or doors, to allow matching windows or doors to be installed, the frame may be disregarded for assessment purposes provided the centre pane U value for each glazed unit is 1.2 W/m²K.

For secondary glazing, an existing window, after alteration should achieve a U value of about 3.5 W/m²K.

There is no maximum U value for display windows.

Pilkington manufactures a range of low emissivity glass for thermal insulation that can help windows and doors to achieve low U-values.

Where a low g value is required, Pilkington provides a range of solar control glass for reducing solar gains in buildings, while maintaining high levels of daylight.

The 2022 editions of the Technical Handbooks can be found here.

Scottish Passivhaus Equivalent

The Scottish Government intends to deliver a Scottish equivalent to the Passivhaus standard. On 12th December 2024, amendments to The Building (Procedure) (Scotland) Regulations were laid in Parliament. This was in response to the commitment made by Ministers in December 2022 to give effect to Alex Rowley MSP’s final proposal for a proposed ‘Domestic Building Environmental Standards (Scotland) Bill’.

Applying to both new homes and new non-domestic buildings, the requirements are expected to be less prescriptive and more flexible than the traditional Passivhaus standard. This suggests the current regulatory approach will be retained, based on a notional building specification but with limiting ('back stop') U values. Products with lower U values are likely to be needed to help deliver the new standard.

A first consultation concluded that the current regulations and mandatory standard which address energy and environmental performance already provide the means to deliver the improvements which are currently sought. A second consultation on detailed proposals for specific changes to performance targets and supporting compliance processes will be launched in summer 2025.

In terms of timings, the new requirements are anticipated to become effective in 2028, introducing changes initially as a voluntary standard from 2026. It is expected that changes to published guidance and approved calculation tools for the confirmed new standard will be made available in 2026.

We will report on more details, as and when they emerge, particularly related to glass and glazing.

Northern Ireland

The Northern Ireland Building Regulations are legal requirements made by the Department of Finance and Personnel and administered by 26 District Councils. The Regulations are intended to ensure the safety, health, welfare and convenience of people in and around buildings. They are also designed to further the conservation of fuel and energy.

The Technical Booklets that support the building regulations in Northern Ireland are listed below and can be accessed here.

Technical Booklet B - Materials and workmanship
Technical Booklet C - Site preparation and resistance to contaminants and moisture
Technical Booklet D - Structure
Technical Booklet E - Fire Safety
Technical Booklet F1 - Conservation of fuel and power in dwellings
Technical Booklet F2 - Conservation of fuel and power in buildings other than dwellings
Technical Booklet G - Resistance to the passage of sound
Technical Booklet H - Stairs, ramps, guarding and protection from impact
Technical Booklet J - Solid waste in buildings
Technical Booklet K - Ventilation
Technical Booklet L - Combustion appliances and fuel storage systems
Technical Booklet N - Drainage
Technical Booklet P - Sanitary appliances, unvented hot water storage systems and reducing the risk of scalding
Technical Booklet R - Access to and use of buildings
Technical Booklet V - Glazing

Technical Booklet E - Fire Safety

Compliance with the minimum standards of fire safety laid down in Building Regulations is crucial in achieving buildings which provide adequate protection for life and property in the event of fire.

The content of the Regulations, the frequency and timing of revisions and the regulatory regimes differ between England and Wales, Scotland and Northern Ireland. However, in each country’s Regulations, glass performs a vital role in achieving the requirements for fire protection. This booklet examines the three sets of Regulations separately, and for each shows how the requirements are met in respect of glazing.

The relevant Regulation is Part E of the Building Regulations (Northern Ireland).

This is supported by Technical Booklet E Fire Safety, compliance with which, like Approved Document B for England and Wales, is taken to demonstrate that the requirements of the Regulation have been satisfied.

Like Approved Document B, Technical Booklet E covers the five basic provisions:

Means of escape
Internal fire spread – linings
Internal fire spread – structure
External fire spread
Facilities and access for the Fire Brigade

In respect of glazing, the requirements of Approved Document B and Technical Booklet E are essentially the same.

The main variance is that a more detailed methodology for determining the limits to the areas of unprotected glazing is given in Technical Booklet E, a methodology which is similar to that appearing in Part D (D6.3) of the Scottish Technical Standards.

Pilkington Fire Protection Glass Range:

Pilkington Pyrostop™

Depending on the thickness, it provides impact safety up to Class 1 BS EN 12600.

Pilkington Pyrodur™

Pilkington Pyrodur™ Plus

Technical Booklet F - Conservation of Fuel and Power

Amendments to Part F of the Building Regulations in Northern Ireland, including the supporting Technical Booklet Guidance, are expected to have a significant impact on glass and glazing products in residential and non-residential buildings. High performance, energy efficient glass and windows are expected to play a crucial role in delivering nearly zero energy buildings (nZEB) in Northern Ireland.

Following an earlier consultation, The Department of Finance (DoF) has published new Technical Booklet guidance to Part F (conservation of fuel and power) of the Building Regulations in Northern Ireland. Applicable from 30th June 2022, the changes apply mainly to new buildings and certain large extensions and are envisaged as an interim step towards nearly zero energy requirements for new buildings.

The new guidance requires new buildings to better the Target carbon dioxide Emissions Rate (TER) by at least the following:

Improvements in TER
New dwellings		New buildings other than dwellings
40% (new houses) 25% (new flats)		15%

To access the new Technical Booklets for Northern Ireland, please click here.

Part F1 - Conservation of fuel and power in dwellings

Amendments to Part F of the Building Regulations in Northern Ireland, including the supporting Technical Booklet guidance, are expected to have a significant impact on glass and glazing products in residential and non-residential buildings. High performance, energy efficient glass and windows are expected to play a crucial role in delivering nearly zero energy buildings (nZEB) in Northern Ireland.

Following an earlier consultation, The Department of Finance (DoF) has published new Technical Booklet guidance to Part F1 (conservation of fuel and power in dwellings) of the Building Regulations in Northern Ireland. Applicable from 30th June 2022, the changes apply mainly to new dwellings and are envisaged as an interim step towards nearly zero energy requirements for new dwellings.

For new dwellings, the Dwelling carbon dioxide Emission Rate (DER) for the proposed dwelling must not be greater than the Target carbon dioxide Emission Rate (TER) based on a notional dwelling of the same size and shape. The new guidance requires new dwellings to better the Target carbon TER by at least 40% for new houses and 25% for new flats.

Limiting values have been set for each element of the building fabric, although achieving the TER may require better performance. The new limiting U values for fenestration elements are summarised in the table below.

Element	Limiting U values for new dwellings (W/m2K)
Element	Area-weighted average	Maximum at any point
Windows, roof windows, glazed rooflights, curtain walling and pedestrian doors	1.4	3.0

There have been no changes to the requirements for existing dwellings (including replacement windows and doors), which remain as follows:

Standards for controlled fittings
Fitting	Standard
Window, roof window, or rooflight	Window Energy Rating (WER) band C or U value = 1.6 W/m2K
Doors with >50% of internal face glazed	U value = 1.8 W/m2K
Other doors	U value = 1.8 W/m2K

We manufacture a range of low emissivity glass for enhanced thermal insulation that can help windows and doors achieve the above U values.

To access the new Technical Booklets for Northern Ireland, please click here.

Through our hub, we will monitor developments as the Part F 2022 consultation progresses and report on the implications as they emerge.

Part F2 - Conservation of fuel and power in buildings other than dwellings

Amendments to Part F of the Building Regulations in Northern Ireland, including the supporting Technical Booklet guidance, are expected to have a significant impact on glass and glazing products in residential and non-residential buildings. High performance, energy efficient glass and windows are expected to play a crucial role in delivering nearly zero energy buildings (nZEB) in Northern Ireland.

Following an earlier consultation, The Department of Finance (DoF) has published new Technical Booklet guidance to Part F2 (conservation of fuel and power in buildings other than dwellings) of the Building Regulations in Northern Ireland. Applicable from 30th June 2022, the changes apply mainly to new buildings and are envisaged as an interim step towards nearly zero energy requirements for new buildings.

For new buildings other than dwellings, the Building carbon dioxide Emission Rate (BER) for the proposed building must not be greater than the Target carbon dioxide Emission Rate (TER) based on a notional building of the same size and shape. The new guidance requires new buildings other than dwellings to better the TER by at least 15%.

Limiting values have been set for each element of the building fabric, although achieving the TER may require better performance. The new limiting U values for fenestration elements in new buildings other than dwellings are summarised in the table below.

Element	Limiting U values for new buildings other than dwellings (W/m2K)
Element	Area-weighted average	Maximum at any point
Windows, roof windows and rooflights	1.6	3.0
Curtain walling	1.8	3.0
Pedestrian doors	1.6	3.0

There have been no changes to the requirements for existing buildings (including replacement windows and doors), which remain as follows:

Standards for controlled fittings
Fitting	Standard
Windows, roof windows and glazed rooflights	U value = 1.8 W/m2K
Alternative for windows in buildings domestic in character	Window Energy Rating (WER) band C
Pedestrian doors with >50% of internal face glazed	U value = 1.8 W/m2K
Curtain walling	Lesser of U value = 1.8 W/m2K or limited value (see note below)

Note - Limited value is dependent upon fraction of opening lights and glazed fraction
We manufacture a range of low emissivity glass for enhanced thermal insulation that can help windows and doors achieve the above U values.

Technical Bulletin F2 also includes a requirement to limit the effects of solar gains in summer. Pilkington provides a range of solar control glass for reducing solar gains in buildings, while maintaining high levels of daylight.

To access the new Technical Booklets for Northern Ireland, please click here.

Technical Booklet H - Stairs Ramps and Barriers

For new buildings and for buildings subject to major refurbishment, the requirements for glazing when incorporated in the designs of stairs, ramps and barriers can be found in the regional Building Regulation Documents.

Northern Ireland

The Building Regulations Northern Ireland 1994, Part H Stairs,Ramps and Guarding.

Technical Booklet H Stairs, Ramps and Guarding 1994, provides guidance on the interpretation of the requirements.

Technical Booklet V - Impact Safety

The Building Regulations Northern Ireland Part V ‘Glazing – safety in relation to impact, opening and cleaning’. Technical Booklet V ‘Glazing’, June gives technical guidance

There are two relevant British Standards:

BS EN 12600 ‘Glass in building - Pendulum test - Impact test method and classification for flat glass’
BS 6262: ‘Code of practice for glazing for buildings’ Part 4 ‘Safety related to human impact’

The various Building Regulations and British Standards have been written separately and at different times. As a result of this, even though the intentions may be the same, the wording and presentation may vary.

However, if the recommendations in BS 6262: ‘Code of Practice for Glazing in Buildings’ Part 4 ‘Safety related to human impact’ are followed, the current requirements of Building Regulations in all three regional areas of the UK for the glazing of critical locations may be satisfied.

Where glazing may also perform the function of guarding (protection against falling through) then the recommendation of the following regulation should also be considered:

Northern Ireland – ‘The Building Regulations Northern Ireland 2006 Part H Stairs Ramps and Guarding’

Energy Efficiency Review

During the second half of 2023, the Department of Finance in Northern Ireland undertook a pre-consultation on the way forward for energy efficiency and related aspects of the Building Regulations. It included proposed measures to ensure new buildings are designed and constructed to net zero ready standards from no later than 2026/27.

Following on from the interim uplift in standards from June 2022, leading to improved building fabric and an increased use of on-site renewables, a proposed uplift in 2023/24 would take into account uplifts introduced to other regions of the UK during 2022/23. An uplift in 2026/27 in Northern Ireland is envisaged to take into account the Future Homes and Future Buildings standards and similar developments in other regions anticipated in 2025.

Two options for the notional dwelling in 2023/24 are under consideration for the next edition of Part F (Conservation of fuel and power), both setting a U value of 1.2 W/m2K for windows and glazed doors, with a limiting U value of 1.4 W/m2K.

Overheating

The pre-consultation also indicates the introduction of a new Part on mitigation of overheating in dwellings, possibly also applying to extensions and alterations.

This would be expected to work on the basis that only a low to moderate risk of overheating assumption would be applicable across the region, similar to the approach in Scotland.

A simplified approach would require an assessment of each room facing west, south or east, including limiting glazing to 20% of the total floor area of the room (or an equivalent reduction supported by shading or a lower g-value for the glass).

Looking ahead to 2026/27, the Department indicated its intention to incorporate minimum fabric standards relevant to existing dwellings with new elements and replacement elements largely in line with the requirements for new dwellings.

For more information on the energy efficiency review, please click here.

Republic of Ireland

In Ireland, the design and construction of buildings is regulated under the Building Control Acts 1990 to 2014, in order to ensure the safety of people within the built environment.

The building regulations apply to the design and construction of a new building (including a dwelling) or an extension to an existing building. The minimum performance requirements that a building must achieve are set out in the second schedule to the building regulations. These requirements are set out in 12 parts (classified as Parts A to M).

Technical Guidance Documents are published to accompany each part of the Building Regulations indicating how the requirements of that part can be achieved in practice. Adopting the approach outlined in a Technical Guidance Document is regarded as evidence of compliance with the requirements of the relevant part of the Building Regulations.

The Technical Guidance documents are listed below and can be accessed here.

Technical Guidance Document A – Structure
Technical Guidance Document B - Fire Safety
Technical Guidance Document B - Fire Safety 2017 Volume 2 Dwelling Houses
Technical Guidance Document C - Site Preparation and Resistance to Moisture
Technical Guidance Document D - Materials and Workmanship
Technical Guidance Document E – Sound
Technical Guidance Document F – Ventilation
Technical Guidance Document G – Hygiene
Technical Guidance Document H - Drainage and Waste Water Disposal
Technical Guidance Document J - Heat Producing Appliances
Technical Guidance Document K - Stairways, Ladders, Ramps and Guards
Technical Guidance Document L - Conservation of Fuel and Energy - Dwellings
Technical Guidance Document L - Conservation of Fuel and Energy- Buildings other than Dwellings
Technical Guidance Document M - Access and Use

Technical Guidance Document B - Fire Safety

Means of escape
Internal fire spread – linings
Internal fire spread – structure
External fire spread
Facilities and access for the Fire Brigade

Pilkington Fire Protection Glass Range:

Pilkington Pyrostop™

Depending on the thickness, it provides impact safety up to Class 1 BS EN 12600.

Pilkington Pyrodur™

Pilkington Pyrodur™ Plus

Technical Guidance Document L - Conservation of Fuel and Power

The requirements for the conservation of fuel and energy in Ireland are covered by Part L of the Building Regulations. New standards for dwellings came into effect in 2003, which meant that low emissivity glass was required in all new and replacement windows in dwellings, and in domestic conservatories.

The Technical Guidance Documents are split into two parts, one for dwellings and the other for non-dwellings.

Technical Guidance Document L for buildings other than dwellings was updated in 2017 to become effective from 1st January 2019. These changes set energy requirement to achieve Nearly Zero Energy Building performance as required under article 1 of the EU Energy performance of Building Directive 2010/31/EU dated 19th May 2010.

For replacement windows in dwellings in Ireland, there is an independent Window Energy Performance (WEP) Certification scheme. The WEP rating is provided for a standard window to represent typical window sizes to enable a comparison of the energy performance of different windows.

Solutions to meet the requirements of building regulations include the Pilkington Optitherm™ and Pilkington K Glass™ ranges of low emissivity glass that can be combined with Pilkington Activ™ self-cleaning glass and Pilkington Optiphon™ to give a broad choice of thermal and other properties. Particularly for non-dwellings, Pilkington Suncool™ is a range of solar control glass products that combine low emissivity glass, low U values with solar control with neutral appearance.

A recent innovation in energy efficiency is Pilkington energiKare™ Advantage which can provide triple glazing performance in a double glazing.

To view details of the full Pilkington range of Thermal Insulation glass to help you meet the new Part L regulations please here.

Technical Guidance Document K - Impact Safety

Building Regulations Part K ‘Stairways, ladders, ramps and guards’. Technical Guidance Document K gives technical guidance

There are two relevant British Standards:

BS EN 12600 ‘Glass in building - Pendulum test - Impact test method and classification for flat glass’
BS 6262: ‘Code of practice for glazing for buildings’ Part 4 ‘Safety related to human impact'

Technical Guidance Document K - Stairs Ramps and Barriers

For new buildings and for buildings subject to major refurbishment, the requirements for glazing when incorporated in the designs of stairs, ramps and barriers can be found in the regional Building Regulation Documents.

Northern Ireland

The Building Regulations Northern Ireland 1994, Part H Stairs,Ramps and Guarding.

Technical Booklet H Stairs, Ramps and Guarding 1994, provides guidance on the interpretation of the requirements.

Architectural and Technical Glass

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