Introduction
Standards and Regulations
The standards and regulations governing the use of glass in buildings are numerous and often complicated. It may be necessary to consult more than one document in order to fully understand the requirements. This page highlights some of the regulations and standards which are commonly encountered when working with glass in buildings. Most of the standards have now been standardised with European Norms and reference is given to these as appropriate.
Building Regulations
Building Regulations are the result, historically, of the need for some form of building control legislation to ensure the health and safety of the inhabitants of buildings. They define how a new building or alteration is to be built so that it is structurally safe, protected from risk of fire, energy efficient and has adequate ventilation for its purpose.
Since their introduction in the1960s, the need to incorporate advances in materials and technology have meant that the regulations have been revised and amended several times. We now have a set of regulations support by Approved Documents. These are publications that give practical guidance on meeting the requirements of the Building Regulations.
Building Regulations now have three purposes:
1. To ensure the health and safety of people in and around buildings.
2. The conservation of energy.
3. Access and facilities for disabled people.
Approval Process:
An application for Building Regulations approval is not advertised in the way that Planning Applications are. Only the person applicant and the Local Authority are involved.
Building Regulations approval may be required even if Planning Permission is not.
Building Regulations approval is granted by the building control officers of local authorities, they are generally separate from the planning officials.
Once approval has been given and work started, the local building inspector will attend the site at specific stages to inspect the work, and they may change the requirements as the work progresses.
General Information
The different types of glass that are used in building are classified by BS 952: 1995 Glass for glazing Part 1 - Classification into three glass compositions - soda lime silicate glass, borosilicate glass and glass ceramics.
It provides terms, definitions and descriptions of the various glass types available and gives details of nominal thicknesses and tolerances.
BS 952: 1980 Part 2 - Terminology for work on glass provides illustrated definitions of terms used in cutting, obscuring, silvering, gilding, staining and bending glass.
The most common glass type used in building is soda lime silicate glass and further detail and classification is provided by BS EN 572: 2004 Glass in building – Basic soda lime silicate glass products Parts 1 to 9.
This European Standard classifies the basic glass products and provides their main physical and mechanical characteristics and general quality criteria. The standard is divided into nine parts. Part 1 gives definitions and general physical and mechanical properties of soda lime silicate glass products and Parts 2 to 9 are each specific to the different product types.
Thermal regulations
Successive advances in glass coating technology have meant that glazing has increasingly become an integral element in improving the energy efficiency of the building envelope and the overall comfort of our living environment.
Heightened environmental awareness has driven legislative pressure to improve the energy efficiency of buildings. Heating, lighting and cooling of buildings accounts for more than 40% of all energy consumption related CO2 emissions. In response, an EU directive on energy performance of buildings (EPBD) has come into force and must now be implemented into the laws of all Member States.
In the UK and Republic of Ireland, the conservation of fuel and power in buildings is controlled by national Building Regulations summarised below:
England and Wales
Governed by the Department for Communities and Local Government (DCLG), Building Regulations for the conservation of fuel and power are covered by Part L and its accompanying "Approved Documents", the most recent amendments to which came into effect on April 6th 2006. In brief summary:
New Build dwellings (ADL1A) and non dwellings (ADL2A)
Designers must calculate the emissions level of the whole building using a standard assessment protocol (SAP) or simplified building energy model (SBEM) to ensure it achieves a target CO2 emissions rating (TER).
Worst acceptable U-value limits for windows, are set at an area-weighted average of 2.2W/m2K and 3.3W/m2K for an individual element.
Renovation of existing buildings
Dwellings (ADL1B) and non-dwellings (ADL2B)
Three alternative methods of compliance:
- Whole window U-value of 2.0W/m2K for dwellings and 2.2W/m2K for non-dwellings, or
- Glass centre pane U-value of 1.2W/m2K, or
- Window Energy Rating (WER) of band E, where the building type is essentially domestic in character
No individual element is permitted to have a U-value worse than 3.3 W/m2K.
Extensions
For small extensions (floor area less than 100m2 and 25% of existing building) ADL1B and ADL2B permit three alternative methods of compliance:
- Whole window U-value of 1.8 W/m2K (% glazing area restrictions apply) or
- Glass centre pane U-value of 1. W/m2K, or
- Window Energy Rating (WER) of band D, where domestic in character.
Larger extensions are considered to be new build.
Window Energy Ratings
One of the most significant changes to new Part L of the Building Regulations for England and Wales is the introduction of the Window Energy Ratings (WER)as an alternative method of compliance for replacement windows.
A window's rating is determined by a formula which takes into account available solar heat gains (window g-value) and subtracts the thermal losses (window U-value and air leakage). The resulting value (energy index) is then placed into a band on an A-G scale consistent with other energy performance labels already familiar to the consumer.
Window Energy Ratings
One of the most significant changes to new Part L of the Building Regulations for England and Wales is the introduction of Window Energy Ratings (WER) as an alternative method of compliance for replacement windows.
A window's rating is determined by a formula which takes into account available solar heat gains (window g-value) and subtracts the thermal losses (window U-value and air leakage). The resulting value (energy index) is then placed into a band on an A-G scale consistent with other energy performance labels already familiar to the consumer.
Improving Window Energy Ratings
The overall performance of a window is dependent on the combined effect of the frame and glazing components and the air-tightness of the finished window. Ratings may be improved by decreasing thermal losses and/or by increasing solar gains.
1) Decreasing thermal losses
Type of Low-E glass: With its optimised balance of very low emissivity and high solar gain SGG PLANITHERM TOTAL+ can improve the energy index for a given window by about 5 kWh/m2/year* when compared to hard coated low-E products.
Inert Gas filling: argon gas filling can improve the energy index for a given window by about 11 kWh/m2/year* compared to an air filled unit.
Optimised cavity width: the optimum cavity width for an argon filled unit is 15mm (10mm with krypton)
Warm edge spacer: Using SGG SWISSPACER can improve the energy index for a given window by about 7 kWh/m2/year* compared to standard aluminium spacer bars.
Triple glazing: can further reduce glazing U-values
Frame type: U-values can be reduced with advanced materials and design
2) Increasing solar gains
low-iron glass: replacing the outer pane with SGG DIAMANT can improve the energy index for a given window by about 6 kWh/m2/year.*
increasing the sighted glass area by changing the frame design to reduce the frame factor
* for a typical PVCu frame with a U-value of 1.8 W/m2K and a frame factor of 30%.
Scotland
The Scottish Building Standards Agency (SBSA) is an executive agency of the Scottish Executive to undertake the national functions related to the new building standards system.
The conservation of fuel and power is covered by section 6 of schedule 5 to regulation 9 (and schedule 6 to regulation 12 for renovation) of the Building (Scotland) Regulations 2004, compliance guidance for which is outlined in sections 6 of the domestic and non-domestic Technical Handbooks, available from the SBSA website.
These regulations are currently under review to take into account implementation of the EU EPBD.
Northern Ireland
The requirements for the conservation of fuel and power are covered by Part F of the Northern Ireland Building Regulations and are governed by the department of Finance and Personnel of the Northern Ireland executive (DFPNI). Guidance on the interpretation of the regulation requirements are provided in the ‘Technical Booklet F, Conservation of Fuel and Power December 1998’ available from the DPFNI website.
These Regulations are however currently under review, to take into account implementation of the EU EPBD and are likely to result in standards similar to those of the rest of the UK.
Republic of Ireland
The requirements for the conservation of fuel and energy are covered by Part L of the Building Regulations and are governed by the Government of Ireland’s Department of the Environment and Local Government (DELG).
New amendments to part L came into effect in July 2006. Essentially maximum whole window U-values of 2.2 W/m2K are now required for new and replacement windows and conservatories in both dwellings and non-dwellings. A new Technical Guidance Document L, containing all the detailed requirements is available from the DELG website.
To conform to the EU EPBD, a ‘Building Energy Rating’ (BER) system was also announced. It is planned that BERs will be mandatory for new dwellings from January 2007, for new non-housing from July 2008, and for all existing buildings when sold or let from January 2009.
Fire
The fire protection of buildings in the UK is controlled by part B of the current Building Regulations for England and Wales.
| Country | Building Regulations |
| England & Wales | Approved Document B |
|
Scotland |
Domestic Handbook Non-Domestic Handbook |
| Northern Ireland | Technical Booklet E |
| Éire | Technical Guidance Document B |
Many other standards apply concerning the manufacturing, installation and testing of fire-resisting products. For further information on fire protection visit www.vetrotech.com
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Not only do Vetrotech products comply with the strictest impact safety requirements, but they are also suitable for multi-comfort applications and meet the aesthetic demands of modern architecture.
Safety & Security
Where people can come into contact with glass, where glass is acting as a barrier to a hazard, such as a fall, or glass is required to provide some additional security, consideration should be given to applicable building regulations and design guides.
Glazing in Critical Locations
Local building regulations throughout the UK and Éire, listed below, provide guidance where safety glass types must be used:
| Country | Building Regulations | Section |
| England & Wales | Approved Document K |
K4 - Protection Against Impact with Glazing |
| Scotland | Domestic Handbook [2] Non-Domestic Handbook [3] |
Section 4.8 - Danger from Accidents |
| Northern Ireland | Technical Booklet V [4] | Section 2 - Limiting the Risk of Impact with Glazing |
| Éire | Technical Guidance Document [5] | Section 1 - Materials |
These documents will typically provide details of areas which are considered critical locations, and they should be consulted when specifying glazing.
Critical locations will typically require a glass that is tested in accordance with EN 12600:2002
Glazing as Guarding
Where glazing is required to act as a guard or barrier, local building regulations provide guidance on the requirements:
| Country | Building Regulations | Section |
| England & Wales | Approved Document K |
K2 - Protection from Falling |
| Scotland | Domestic Handbook [2] Non-Domestic Handbook [3] |
Section 4.4 - Pedestrian Protective Barriers |
| Northern Ireland | Technical Booklet H [7] | Section 5 - Guarding |
| Éire | Technical Guidance Document K [8] | Section 2 - Pedestrian and Vehicle Barriers |
These documents make reference to various codes and standards to assist with determining suitable glass types and thicknesses.
| Codes of Practice | Test Standards |
|
EN 1990:2002 EN 1991-1-1:2002 PD 6688-1-1:2011 BS 6180:2011 BS 6262-4:2005 |
EN 12600:2002 BS 6206:1981 |
The required thickness of glass is typically determined by calculation, and will compare the stress and deflection generated in glass under prescribed loadings, based on circumstance and building occupancy, to allowable limits. Guarding calculation request forms can be found on SGG Live, or contact the SGG UK Marketing department for more information.
Security Glazing
Where there is a requirement for additional security, such as when designing to Secured By Design Guides (www.securedbydesign.com), or Building regulations Approved Document Q
6.8 mm STADIP and STADIP SILENCE will meet a P2A classification, and so exceed the requirements of P1A.
Referenced Documents
|
[1] |
HM Government, The Building Regulations 2010 - Approved Document K - Protection from falling, collision and impact, 2013. |
|
[2] |
Riaghaltas na h-Alba, Technical Handbook 2015 - Domestic, Riaghaltas na h-Alba, 2015. |
|
[3] |
Riaghaltas na h-Alba, Technical Handbook 2015 - Non-Domestic, Riaghaltas na h-Alba, 2015. |
|
[4] |
Department of Finance and Personnel, Building Regulations (Northern Ireland) 2012 Guidance - Technical Booklet V - Glazing, DFPNI, 2012. |
|
[5] |
Environment, Community and Local Government (Éire), Building Regulations 2013 - Technical Guidance Document D - Materials and Workmanship, Government Publications (Éire), 2013. |
|
[6] |
European Committee for Standardization, EN 12600:2002 - Glass in building - Pendulum test - Impact test method and classification for flat glass, CEN, 2002. |
|
[7] |
Department of Finance and Personnel, Building Regulations (Northern Ireland) 2012 Guidance - Technical Booklet H - Stairs, ramps, guarding and protection from impact, DFPNI, 2012. |
|
[8] |
Environment, Community and Local Government (Éire), Building Regulations 2014 - Technical Guidance Document K - Stairways, Ladders, Ramps and Guards, Government Publications (Éire), 2014. |
|
[9] |
European Committee for Standardization, EN 1990:2002 - Basis of structural design, CEN, 2002. |
|
[10] |
European Committee for Standardization, EN 1991-1-1:2002 - Eurocode 1. Actions on structures. General actions. Densities, self-weight, imposed loads for buildings, CEN, 2002. |
|
[11] |
European Committee for Standardization, NA to BS EN 1991-1-1:2002 - UK National Annex to Eurocode 1. Actions on structures. General actions. Densities, self-weight, imposed loads for buildings, CEN, 2002. |
|
[12] |
European Committee for Standardization, NA to IS EN 1991-1-1:2002 - Irish Annex to Eurcode 1 - Actions on structures - Part 1-1: General actions - Densities, self-weight, imposed loads for buildings, CEN, 2002. |
|
[13] |
British Standards Institute, PD 6688-1-1:2011 - Recommendations for the design of structures to BS EN 1991-1-1, 2011: BSI. |
|
[14] |
British Standards Institute, BS 6180:2011 - Barriers in and about buildings. Code of practice, BSI, 2011. |
|
[15] |
British Standards Institute, BS 6262-4:2018 - Glazing for buildings - Code of practice for safety related to human impact, BSI, 2018. |
|
[16] |
British Standards Institute, BS 6206:1981 - Specification for impact performance requirements for flat safety glass and safety plastics for use in buildings, BSI, 1981. |
|
[17] |
HM Government, The Building Regulations 2010 - Approved Document Q - Security - Dwellings - Unauthorised access, 2015. |
|
[18] |
European Committee for Standardization, EN 356:2000 - Glass in building. Security glazing. Testing and classification of resistance against manual attack, CEN, 2000. |
Acoustic insulation
Noise is simply categorised as unwanted sound. In order to assess the impact of the surrounding environment, such as roads/motorways, factories, airports, etc, on people, noise assessment can be carried out. These assessments will typically involve the monitoring of sound over a set time period using a sound level meter with an A-weighted filter.
The A weighting is used to simulate the response of the human ear with respect to the various audible frequencies, and is defined in EN 61672-1:2013
In addition, octave band A weighted sound pressure levels can also be measured to provide more information relating to the specifics of the noise at the location, and enable glazing, and other façade elements to be more appropriately selected.
The requirements will often be provided in a format similar to the below:
| Position | Leq Sound Pressure (dB) at Octave Band Frequency (Hz) | dB(A) | ||||||
| 63 | 125 | 250 | 500 | 1000 | 2000 | 4000 | ||
| A Leq, 16hour |
60 | 55 | 52 | 47 | 48 | 42 | 33 | 52 |
Noise Limitations
The noise levels within various buildings, for various activities and times of day, are defined by BS 8233:2014
| Activity | Location | 07:00 to 23:00 | 23:00 - 07:00 |
| Resting | Living Room | 35 dB Laeq,16hour | ---- |
| Dining | Dining Room/Area | 40 dB Laeq,16hour | ---- |
| Sleeping | Bedroom | 35 dB Laeq,16hour | 30 dB Laeq,16hour |
Other requirements apply for buildings with other uses, and are defined within BS 8233:2014.
For partitions within offices, some guidance is provided within BS 5234-1:1992
Glazing Selection
When selecting glazing based on acoustic performance, there are two main criteria to consider, weighted values and octave centre band values. Testing of acoustic performance in accordance with ISO 10140-2:2010
Octave Band Values
The testing provides performance at third octave band centre frequencies, from which the performance at octave band centre frequencies can then be calculated, again, in accordance with EN 10140-2:2010. For this reason, the performance at the one third octave band centre frequencies will not typically match that for the respective octave band centre frequencies, as below.
| Third Octave Band Centre Frequency (Hz) | R1/3OCT (dB) | ROCT(dB) | Octave Band Centre Frequency (Hz) |
| 50 63 80 |
31 35 29 |
31 | 63 |
| 100 125 160 |
29 28 27 |
28 | 125 |
| 200 250 315 |
28 32 34 |
31 | 250 |
| 400 500 630 |
38 40 42 |
40 | 500 |
| 800 1000 1250 |
44 43 39 |
42 | 1000 |
| 1600 2000 2500 |
39 44 49 |
42 | 2000 |
| 3150 4000 5000 |
53 57 57 |
55 | 4000 |
Ctr and C are the spectrum adaptation terms for traffic noise and pink noise respectively, and give an indication of how the glazing will perform with respect to noise from the related sources. When subtracted from the Rw weighted performance, the Rw,Ctr and Rw,C values are obtained. ISO 717-1:2013 also provides some examples of noise sources relevant for these adaptation terms, as below:
| Adaptation Term | Noise Source |
| C | Living Activities (Music, Radio, TV) Children Playing Locomotive - Medium & High Speed Automotive - >80 km/h Jet Aircraft - Short Distance Factories - Medium & High Frequency Noise |
| Ctr | Urban Road Traffic Locomotive - Low Speeds Aircraft - Propeller Driven Jet Aircraft - Distant Disco Music Factories - Medium & Low Frequency Noise |