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Specifiers' Handbooks for Inclusive Design

Glass in Buildings

This guide has been produced by the Centre for Accessible Environments in conjunction with RlBA Publishing. Text by Ann Alderson B/Arch (Edin) RlBA Drawings and editing by Alison Grant MA Arch RlBA NRAC Consultant Case studies researched and compiled by Ann Alderson and Adrian Cave Photographs, unless otherwise acknowledged, by Ann Alderson and Paul Highman Cover photo by Paul Highman Published: September 2006 0 Centre for Accessible Environmentsand RlBA Publishing

ISBN-10 1 85946 254 5 ISBN-13 978 1 85946 254 6 Stock Code 59231 Centre for Accessible Environments 70 South Lambeth Road London SW8 1RL Telrtextphone: +44 (0)20 7840 0125 Fax: +44 (0)20 7840 5811 Email: [email protected] Website: www.cae.0rg.uk The Centre for Accessible Environments is a Company Limited by Guarantee registered in England and Wales No 3112684, Registered Charity No 1050820. RlBA Publishing 15 Bonhill Street London EC2P 2EA Tel: +44 (0)20 7496 8300 Fax: +44 (0)20 7374 8200 Email: sales9ribabooks.com Website: www.ribabookshops.com RlBA Publishing is part of RlBA Enterprises, a Company Limited by Guarantee registered in England and Wales No 978271. Designed by Steve Paveley Design Typeset by Academic + Technical Typesetting, Bristol Printed and bound by Latimer Trend, Plymouth

Foreword All building users should be able t o enter and move around a building with the confidence that the doors, windows and balustrades they walk past or through are safe t o use. Sadly, glass related accidents and injuries due t o human impact with glazing products are all too common. Many of these accidents involve pain, suffering, broken bones and even death, and often occur because the glass or glazing material is either not visually apparent t o the building user, is not a safety glass, or robust enough t o withstand human impact. Part of the Health and Safety Commission's programme t o reduce the number of accidents in the UK is t o produce i t s own guidance, or t o sponsor/endorse industry-written practical guidance for those who design, procure and manage architectural glazed elements in buildings. This Specifiers' Handbook is designed t o facilitate a practical understanding of how t o provide glazed elements that enable all users of all abilities t o be safe as they walk around the buildings they use. Getting it right by design.

The handbook covers the different uses of glass in buildings, including windows, doors, walls and partitions, balustrades, glazed entrance ways, floors, stairs, lifts, vision panels, protective screens, roof lights, display cases, conservatories, shower screens, signs and mirrors. This information should assist those responsible for the selection and specification of each element t o make decisions that will lead t o the procurement of the most suitable product, and will also assist people who are responsible for ongoing maintenance t o understand the importance of regular checks. The Health and Safety Executive were delighted t o sponsor this Centre for Accessible EnvironmentdRIBA Enterprises publication which should prove invaluable t o designers, building owners and occupiers, building managers and facility managers in discharging their responsibilities for inclusive design in buildings of all types. Stephen Taylor RlBA Principal Specialist Inspector Construction Division Technology Unit Health and Safety Executive

Acknowledgements We are grateful t o HSE for sponsorship of this guide. Reviewed by: John Colvin, Hansen Glass David Petherick, Department for Communities and Local Government lain Slessor, Museums, Libraries and Archives Council Geoffrey Street, BAA Stephen Taylor, Health and Safety Executive Timothy Thurston, JMU Access Partnership Brain Waldron, JBW Glass, on behalf of the Glass and Glazing Federation

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Contents Page 1 Introduction Inclusive design Specifiers' Handbooks series About this handbook 2 The legislative framework Building Regulations England and Wales Scotland Northern Ireland Disability Discrimination Act 1995 Construction Products Regulations 1994 CE Marking The Workplace (Health, Safety and Welfare) Regulations 1992 Construction (Design and Management) Regulations 1994 3 Design and specification guidelines British and European Standards Other standards Design issues Risk assessment Human impact resistance/safety Visibility/transparency Glare Reflection Acoustic environment Psychologica I comfort Technical guidelines Windows Glass walls and partitions Glass roofslatria Glazed entrances, doors and screens Guards and barriers Glass floors including bridge decks and accessible roofs Glass stairs Glass lifts Glass screens a t counters Vision panels RoofI ights Display cases Conservatories Shower screens Mirrors Glass signs Historic buildings

3 3 3 3 3 3 4 4 5 5 7 7 8 8 9 9 11 14 17 18 18 19 19 20 21 22 24 26 28 28 30 30 31 32 34 34 34 35 35 V

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4 Building management Cleaning and maintenance Inspection Repair and replacement 5 Case studies Paddington Station, London Glass with minimal manifestation Tate Modern - new glass shop Dulwich Picture Gallery - new extension

39 39 39 39 41 41 43 43 46

6 Appendices Types of glass Adhesive backed polymeric films Legislation Building Regulations Disability Discrimination Acts 1995 and 2005 Disability Equality Duty Sources of useful information Organisations Pub1ications

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Introduction Inclusive design Inclusive design is a process that delivers an environment where everyone can access and benefit from the full range of opportunities available t o members of society. It aims t o remove barriers that create undue

effort, separation or special treatment, and enables everyone regardlessof disability, age or gender t o participate equally, confidently and independently in mainstream activities with choice and dignity. Inclusive design: places people a t the heart of the design process responds t o human diversity and difference offers dignity, autonomy and choice provides for flexibility in use

Specifiers' Handbooks series The Specifiers' Handbooks for Inclusive Design series comprises a set of design guides which look in detail a t the technical aspects of key building elements. The series expands on guidance in Designing for Accessibility, a leading CAE/RIBA Enterprises publication covering inclusive design in a range of public buildings. The Specifiers' Handbooks for Inclusive Design series has been prepared t o assist designers, specifiers, building owners and occupiers, building managers and facilities managers t o understand key design aspects and characteristics of specific architectural elements in non-domestic buildings. The series combines technical guidance with informative case studies, designed t o facilitate a practical understanding of the element in focus. The first

five handbooks in the series cover: Platform l i f t s Architectural ironmongery Automatic door systems Use of glass in buildings Internal floor finishes The information in the handbooks should assist people responsible for the selection and specification of each architectural element t o make decisions that will lead t o the procurement of the most suitable product. The information will also assist people who are responsible for ongoing maintenance t o understand the importance of regular checks and the implications for disabled and other people if a facility or component is taken out of action for any reason.

About this handbook This handbook covers the design criteria and detailed aspects of the different uses of glass in buildings, including windows, doors, walls and partitions, balustrades, glazed entrance ways, floors, stairs, lifts, vision panels, protective screens, rooflights, display cases, conservatories, shower screens, signs, and mirrors. It does not cover glass furniture or fittings, such as shelves. The handbook offers practical guidance to help designers, specifiers and facilities managers understand the design criteria for the inclusive use of glass in buildings, the different types of glass available, related legislation, building regulations and standards and operation and maintenance issues. The design guidance is supported by illustrations and case study examples that illustrate different uses of glass in a range of situations. Glazing in buildings can also be provided by transparent plastic material. These are not specifically covered in this handbook, although much of the guidance will be applicable.

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The legislative framework Building Regulations Glass is almost always installed as an integral part of any new development, and may be installed where improvements are being made t o existing buildings. All new developments are subject t o approval under Building Regulations, in which case the provisions in the relevant Approved Document, Technical Handbook or Technical Booklet will be applicable. Depending on the nature and extent of building improvements, approval under Building Regulations may or may not be required.

England and Wales Approved Document M: Access to and use of buildings 2004 edition (AD M) incorporates provisions relating t o the use of glass in entrance doors and glazed screens (Section 2) and glazed screens a t reception counters, internal glass doors and screens, and the provision of vision panels (Section 3). Approved Document N: Glazing - safety in relation to impact, opening and cleaning 1998 edition incorporating 2000 amendments (AD N) covers protection against impact, the manifestation of glazing, safe opening and closing of windows, and safe access for cleaning. Approved Document K: Protection from falling, collision and impact 1998 edition incorporating 2000 amendments (AD K) covers the use of glass when incorporated into the design of guards and barriers and the provision of vision panels on circulation routes (although the dimensional guidance for vision panels is superceded by AD M). if there is a conflict between the guidance in AD N, AD K and AD M, the latest version takes precedence. AD N is due t o be revised, based on the new British Standard BS 6262:2005 Glazing for buildings.

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Scotland There are two Technical Handbooks, a Domestic Handbook and a Non-domestic Handbook, which provide guidance on achieving the standards set in the Building (Scotland) Regulations 2004. Guidance is available in Section 4: Safety of the Non-domestic Handbook in relation t o principal entrances, internal doors, the use of glass in protective barriers, and collision with glazing.

Northern Ireland Technical Booklet H: 2000 - Stairs, ramps, guarding and protection from impact provides guidance on the use of glazing in guarding and protection against impact from and trapping by doors. Technical Booklet R: 2000 -Access and facilities for disabled people covers the use of glass in entrance and internal doors. Technical Booklet V: 2000 - Glazing covers the use of glass generally. A general discussion of the Building Regulations is included in the Appendices.

DisabiIity Discriminat ion Act 1995 Elements of buildings and environments which are constructed of glass or incorporate glass in other components may be considered t o be a 'physical feature' under the Disability Discrimination Act 1995 (DDA). Glass in windows and doors, glass floors, balustrades, lift enclosures and mirrors are a few examples, all of which contribute t o the usability, safety and appearance of the built environment. Glass has traditionally been used for windows in nearly all buildings t o let light into the interior spaces. It is now increasingly being used in nontraditional, innovative ways due t o its aesthetic and psychological appeal but, if not designed 3

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and specified correctly, it can create potential barriers or hazards for building users. The DDA places duties on service providers, employers, providers of post-16 education and others t o make reasonable adjustments to physical features where they present a potential barrier t o access or the use of facilities. Reasonable adjustments may involve the removal or alteration of a barrier, or the provision of an alternative means of access. For example, an unframed clear glass screen and door in an existing building presents a potential hazard t o all building users, but particularly t o visually impaired people. The addition of effective manifestation t o the glass, and the provision of visually contrasting edge strips t o the door is likely t o constitute a 'reasonable adjustment', designed t o clearly highlight the presence of the glass. Increasing the size of vision panels t o a series of internal doors t o provide a zone of visibility suitable for people a t a range of eye levels might constitute a reasonable adjustment under the Act. The extent and nature of any adjustment will depend on the particular characteristics of the element, and on other factors such as practicality, the extent of disruption, the effectiveness of the adjustment, and cost. The duty is t o make reasonable adjustments, having taken into account all the relevant factors. Duties under the DDA do not only relate t o the adjustment of physical features. They also relate t o policies, practices and procedures, all of which could have a significant effect on the safety, accessibility and usability of the glass element or component. These duties include cleaning and maintenance of the glass and any fixings associated with it. The DDA does not place duties on product designers and manufacturers in relation t o the type of products, packaging or instructionsthey offer, on the basis that they do not involve the provision of a 'service' direct t o the general public. Product designers and manufacturers themselves have no duties under the Act t o produce accessible products. However, those 4

who are responding t o their duties t o make reasonable adjustments will want t o procure products and components that are designed t o maximise accessibility and meet the needs of a broad range of people. Further details on the Disability Discrimination Acts 1995 and 2005 are included in the Appendices.

Construction Products Regulations 1994 The UK Construction Products Regulations(CPR) require construction products t o be safe when incorporated into a building. The Regulations have six categories, five of which apply t o glass: mechanical resistance and stability safety in case of fire safety in use protection against noise energy economy and heat retention All products supplied t o a building that is subject t o Building Regulations have t o satisfy the requirements contained in these Regulations.Compliance with these regulations can be most easily demonstrated by producers CE Marking their products. Although CE Marking is not a mandatory requirement in the UK, it is in most other EU countries, and many producers are already following this route.

CE Marking CE Marking is the manufacturer's declaration that the product meets the requirements of the relevant European Directives as implemented by national legislation such as the CPR. CE Marking verifies that:

the product meets the requirements of the Construction Products Regulations it has been satisfactorily tested by a third party t o verify standards established by a relevant harmonised European Standard there is the required level of factory production control a t the manufacturing facilities, and that this is subject t o regular third party checks

CE Marking for glass commenced in 2005 in accordance with a number of recently published European Norms. Further information can be found on the website of the European Association of Flat Glass Manufacturers: www.gepvp.org

The Workplace (Health, Safety and Welfare) Regulations 1992 Glass and glazing are covered under Regulation 14 of The Workplace (Health, Safety and Welfare) Regulations 1992. This Regulation states that every window, or other transparent or translucent surface in a wall, partition door or gate should, where necessary for reasons of health or safety: be of safety glazing material be protected against breakage of the transparent or translucent material be appropriately marked or incorporate features so as t o make it apparent Glazing which conforms t o Part N of the Building Regulations or t o BS 6262-4:2005 Glazing for buildings. Code o f practice for safety related to human impact is likely t o

satisfy this regulation. In other cases, it will be necessary t o undertake an assessment of the risks associated with the glazing, taking account of the activities around it and any previous accidents associated with it. Where glazing in an existing building is changed it should conform t o BS 626242005, and other regulations relating t o glazing such as fire performance. There may be exceptions, in some circumstances, for example, for historic buildings.

Construction (Design and Management) Regulations 1994 Regulation 3 of the Construction (Design and Management) Regulations 1994 (CDM) requires designers t o 'prepare designs with adequate regard t o health and safety'. These regulations apply t o new building and refurbishment work during the construction process and for maintenance of parts of the buildings with residual risks. Proposed revisions t o the CDM Regulations may extend designers' responsibilities t o the health and safety of users of workplaces.

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Design and specification guidelines British and European Standards A number of British and European Standards are applicable t o the selection, installation and use of glass in buildings, as well as t o the manufacture, testing and marking of glass. The standards are not normally compulsory, but demonstrate good practice and generally satisfy the regulations mentioned in the previous section. Other solutions may also comply with the regulations. The following standards are of particular relevance t o the use of glass in buildings: BS 6262:2005 Glazing for buildings

This recently revised standard is in seven parts. It gives recommendations for the design, installation and maintenance of vertical glass and plastics glazing sheet materials for buildings apart from patent glazing and barriers. Parts 1, 2, 4 and 6 are relevant t o this document: Part 1: General methodology for the selection of glazing Sets out a methodology for the design and selection of glazing and addresses the legislation and criteria that need t o be considered. Part 2: Code of practice for energy, light and sound Gives information and recommendations for vertical glazing in buildings with respect t o their effect on energy, light and sound environments in the building. Part 4 Code of practice for safety related to human impact This part essentially mirrors AD N, but extends 'critical locations' t o include bathing areas and gymnasia. It also contains further explanation and guidance. It refers t o EN

product standards (see Appendices for further details) and EN 12600:2002, which covers the classification and marking of flat glass. This new code of practice will be the basis for the revision of Part N. Part 6: Code of practice for special applications Gives information and recommendations for vertical glazing in external walls and interiors of buildings in relation t o structural sealant and bolt fixed glazing, frameless doors and entrances, and mirrors. BS 6180:1995 Code of practice for barriers in and about buildings This standard provides recommendations for the design and construction of barriers used for protection from changes in level, or as a means of restricting or controlling movement of people and vehicles. It includes guidance on glass and glazed barriers. BS 8300:2001 (Incorporating Amendment No. 1) Design of buildings and their approaches to meet the needs of disabled people - Code of practice BS 8300:2001 provides good practice guidance for the design of non-domestic and domestic buildings and their approaches. The document is comprehensive and covers features such as car parking provision, setting-down points and garaging, access routes t o and around all buildings, entrances to, and interiors of new buildings.

Glass is covered in BS 8300:2001 in relation t o entrance doors and glazed entrances, internal doors, vision panels, corridor lighting, surfaces, windows, glazed walls and screens, screens a t counters, display cases and mirrors in lifts and lavatories.

Amendment No.1 t o BS 8300:2001 was published in June 2005 and incorporates 7

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Glass in Buildings

additional guidance on a number of issues including visual contrast and the design of principal entrance and internal doors.

Other standards There are many other British and European standards relating to glazing, glass types, instaIlation, safety, security, fire, workmanship and other matters. These are listed in the Appendices.

Design issues With improved material and construction technology, glass is being increasingly used for many different elements and purposes, from traditional windows for daylighting, to newer uses for architectural effect, visual integration of spaces and increased natural lighting in internal areas.

- -I A glass and timber bridge linking two buildings over a street Glass is an extremely versatile material that can be used in a wide variety of applications t o produce interesting, functional buildings with great aesthetic appeal. However, it must be designed and specified with great care so that i t s inherent positive characteristics are optimised, and it does not adversely affect the safety, accessibility or usability of the building by everyone.

There are a wide variety of types of glass with different characteristics to meet different requirements including annealed glass, safety glass (comprising laminated, toughened and wired glass), security glass and specialist glass with specific properties including fire resistance, reduction in solar gain, thermal insulation, vision control, anti-glare and acoustic insulation. Glass for use in buildings and environments must be carefully selected t o meet the relevant standards and t o achieve the required design characteristics.

I 30 St Mary Axe, the 'gherkin', has a fully-glazed double-skinned facade, cooled by extracted air from the offices. The facade is designed for safe, efficient access for cleaning and maintenance 8

There are many design criteria relating to the use of glass in buildings, including functional, practical, safety, aesthetic, financial and environmental issues. All of these are important and have t o be considered and balanced in the final design of any glazed element. This handbook focuses on design and technical issues which have a particular impact on the inclusive design of buildings, while acknowledging that the other criteria are equally relevant. Building Regulations and British or European Standards cover some of the issues, but it should be noted that these are

minimum requirements and simply meeting them may not make glazing in a building acceptable and usable by all. Available guidance on the other design issues is given in the Appendices.

the users and their activities. In the case of an existing building it is also necessary to identify the type of the existing glass in order t o assess its performance under impact and the consequences of an accident.

Risk assessment

The following sections cover general design issues that are common t o most uses of glass in buildings.

Where extensive use of glass is proposed, or where there are critical conditions or requirements, a risk assessment should be carried out. This would normally cover: safety risks t o people during construction, normal use, cleaning, maintenance and repair building performance risks during construction financial risks at any stage of the building life cycle The safety of people during the normal use of a building or environment is the most important factor. For this, an assessment would take into account the risk of accident with a particular glazed element and the likely consequences of the accident. For example, there may be a risk of collision with a pane of glass or barrier due t o inadequate identification or disorientation caused by i t s transparency, with the possible consequence of falling and injury. To undertake a full assessment it is necessary t o know the use of the building or environment, the nature of

I Figure 1 Critical locations

Human impact resistancehafety Glass presents a particular issue with regard to human impact because, in addition t o the risk of bruising, fracture or break injuries as with other construction materials, there is the risk of the glass breaking leading t o piercing and cutting by the glass fragments. Therefore, when glass is used where it could be subject t o human impact, it must normally either be protected by a physical barrier, or must be classified and marked as safety glass.

AD N (England and Wales), Section 4 of the TechnicaI Handbook for non-domestic buildings (Scotland) and Technical Booklet V (Northern Ireland) set out requirements for resisting impact and the safe breakage of glass. They also define 'critical' locations in external and internal walls where the risk of human impact and accident is increased, such as doors and side panels t o doors and low-level glazing in windows and partitions, see Figure 1.

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BS 626242005 extends critical locations t o swimming pools and bathrooms, and buildings with special activities such as gymnasia. Research has identified other building types or areas used by high-risk groups (children, older people) including schools and hospitals as potentially critical locations.

Safety glass, as defined in BS 6206:1981 Specification for impact performance requirements for flat safety glass and safety plastics for use in buildings, is glass that does not break or breaks safely in the event of a soft body impact. Safe breakage is when the broken pieces of glass do not have sharp or pointed protrusions. Test methods and classification for safety glass are given in BS EN 12600:2002. Three generic types of glass meet the requirements for safety glass: toughened glass, laminated glass and safety wired glass. All safety glass must be marked in accordance with BS 6262-4:2005 t o include the following information:

Typical marking for toughened glass accordance with Glass and Glazing Federation (GGF) recommendations. This marking is essential for assessment of compliance with Regulation 14 of the Workplace (Health, Safety and Welfare) Regulations 1992.

an identifiable name, trademark or other traceable identification mark the number of the British European Standard for the product the impact classification according t o BS EN 12600:2002

Glazing in a critical location, which has permanent physical protection, does not need t o be safety glass, provided that the screening meets the following criteria:

The marking must be on each sheet of cut glass or pane, permanent and in a position that it remains visible after installation. Marks are normally placed on the bottom right hand corner when viewed from the inside, in

is independent of the glazing can prevent a 75mm sphere from coming into contact with the glazing is robust enough t o withstand an applied force of 1350 newtons if less than 900mm, or

Glass or plastic

screen

Figure 2 Permanent screen protection 10

Design and specification guidelines

1100 newtons if greater than 800mm in length without fracturing, deflecting so as to impact the glass, or being permanently distorted or displaced is difficult to climb if it is intended to protect glazing that forms part of a protection from falling; horizontal rails should be avoided

VisibiIitykanspa rency Large, uninterrupted areas of transparent glazing represent a significant risk of injury through collision, as building users may be unaware of the presence of a physical barrier. The risk is a t its highest when large panes of glazing are used between areas of a building or its surroundings that are a t the same level, where a person might reasonably assume that there is direct access rather than a transparent barrier. Similarly, unframed glass in balustrades may not be apparent.

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A full-height glass screen encloses this

The presence of transparent glazing should always be indicated by manifestation, although AD N states that physical means, such as framing, a middle rail or large push plates could satisfy the requirements.

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staircase, providing a visual link and allowing light into the adjacent entrance and cloakroom area. Manifestation is provided at two levels but is barely visible and is unlikely to highlight the presence of the glass

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A fully-glazed screen visually integrates the main station with the retail area 11

Glass in Buildings

Decorative feature such as repeated dots or broken lines at least 50mm high

Decorative logo 150rnm min height

above floor level

above floor level

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High-contraststrips to top, bottom and both sides of glazed door to clearly differentiation from glazed screen

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Glazing clearly defined with manifestationat two levels

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Figure 3 Markings for safety and visibility

Manifestation should either be permanent, such as etching or coloured glass, or be a durable applied material that cannot easily be removed. AD M recommends that it should consist of two broken or solid lines of patternscompany or decorative bands a t heights of 850-1000mm and 1400-1600mm above floor level. Repeated decorative features should be a t least 100mm high and decorative logos 150mm high, see Figure 3. Proposed revisions to AD N, published in January 2006, include a suggestion that manifestation should cover a minimum of 10 per cent of the glazing within the defined viewing zone, proposed as 850-1600mm above floor level. This differs from the recommendation in AD M of manifestation a t two heights, but would ensure that the manifestation is sufficiently large and would allow large-scale graphics and patterning. In addition it is suggested that there should be an opaque skirting from the ground up to a t least 400mm.

when viewed against a variety of backgrounds. Manifestation consisting solely of etched glass probably will not show up against complex backgrounds. Care should be taken where there are different levels of lighting on either side of the glazing, which may result in reflection or glare, reducing the visibility of the manifestation. Alternative effective means of highlighting the presence of glass include: the use of narrow sections of glass (up to 400mm width between frames) the provision of a horizontal rail or framing member between 600mm and 1500mm above floor level the use of a substantial frame to a single pane glazed door A change in floor surface either side of full-height glazing may help to highlight the presence of glass, and, if heavily textured, prevent people from getting too close.

It is recommended that the markings are visible

against a variety of internal and external backgrounds, and in different lighting and weather conditions. This can be difficult to achieve in practice with a single tone material. A two-tone material is likely to be more effective a t achieving effective visual contrast 12

Unframed floor to ceiling glazing may make it difficult for people to comprehend the size and shape of a space due to lack of perimeter definition a t floor level, creating confusion and disorientation. This can be resolved by providing a rail or physical barrier a t floor level,

Design and specification guidelines

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The manifestation on this glazed wall does not conform to standard recommendations, but is clearly visible in all conditions and effectively highlights the presence of the glass when viewed from a distance

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The manifestation is clearly visible against the background surfaces viewed through the glass

The use of different colours and bold icons helps to make this manifestation clearly visible, even though there are strong reflections on the glass 13

Glass in Buildings

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Etcnrng can be used both as manifesrarron and for privacy, while still allowing light to pass through the glass and provide a visual link

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This glass structure is physically protected by the stone plinths and by a change in floor texture which will also protect t h e glass from damage by buggies and wheelchair footrests.

Large, round, white pebbles externally contrasting with the internal floor finish provide a visible border to the foot of the glazing

Glare The use of glass in a building can improve daylight conditions and integration of t h e internal and external spaces, but it can also

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Glazing less than 400mm in width between frames

Glazing with a rail between 600 and 1500mm above the floor

A single pane glazed door with a substantial frame

Figure 4 Examples of door height not warranting manifestation 14

Glazed doors with no frame or narrow frames, but with a large handle or push plate on each single pane

Design and specification guidelines

Glare from the windows on the shiny floor make it difficult to define the edge of the balcony and distinguish the glazed barrier have the negative effect of introducing glare, either directly or by reflection, which will adversely affect visual performance. Glare can impair vision - disability glare, or cause discomfort - discomfort glare. These can occur simultaneously or separately. Both are unpleasant and may be a potential hazard by affecting vision or causing disorientation. Glare can make it difficult for people t o lip read. Disability glare, or veiling luminance, is caused by scattered light within the eye. It results from excessive contrast of illumination. This can increase with age, and becomes considerably worse for a person with cataracts. The most common sources of disability glare inside a building are the sun and sky seen through windows. It is most likely t o occur when an area close t o the line of sight is of much higher luminance than the subject being regarded, for example, objects being viewed against a bright window or a window a t the end of a corridor. This results in the object becoming a silhouette with little detail visible. Discomfort glare results from an excess of illumination in the field of view and occurs, for example, when a person is looking through a window in the direction of the sun, or when direct sunlight falls on a light-coloured surface in the immediate field of view. South facing windows are highly likely t o cause glare, and low sun on southwest or southeast facing

This column-mounted sign in a building with curtain walling is unreadable for much of the day, as the glare from the bright external environment is causing it to be silhouetted windows can dazzle. It can also occur when an overcast sky is viewed through glazing. Particular care should be taken with windows a t the end of corridors or on staircases, and behind signs, counters, seating and other places where people or objects need t o be seen in detail. Textured or acid etched glass is more likely to be a discomfort glare source due t o the diffusion of light. The following measures can be taken t o reduce the likelihood of glare: minimising the contrast between the glazed area and the surrounding walls and floors arranging the internal layout so that the sky, seen through a window or glazed wall, does not lie in the immediate field of view of an object or task screening the glazing by curtains, blinds, louvres or shutters: the use of these may also reduce daylighting. Curtains and internal blinds will reduce glare, but external blinds shutters will also reduce solar gain. The operation, cleaning and maintenance implications need to be considered avoiding the use of specular (highly reflective) surfaces adjacent t o the glazing using tinted glass (lighting levels and thermal requirements will also need t o be considered as these will be affected by the degree of tinting) using reflective coated glass which reflects a proportion of the daylight (but the risk of 15

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Adjustable, internal vertical blinds can help to prevent glare, reduce solar heat gain and highlight the presence of a glazed wall or screen

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External etched-glass louvres provide solar shading and privacy while still transmitting light into the internal space

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Adjustable, aluminium louvres between the double-skinned glazed facatde provide solar shading and highlight the presence of the glazing 16

Design and specification guidelines

reflection externally should also be considered) using absorptive coated glass, which absorbs a proportion of the daylight using anti-glare film that reflects or absorbs some of the daylight using screen-printed glass reducing the brightness contrast between the sky seen through the glazing and the surrounding wall by making the latter light coloured and having splayed reveals using slender glazing bars and transoms that have high reflectance

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Reflections in a glazed facade can make it difficult to see the manifestation and could cause visual confusion

Guidance on daylighting and glare is given in BS 6262-2:2005.

significantly different levels, are likely t o cause reflections. The angle of the glass in relation t o the light source, may increase or decrease reflection. Reflections that create patterns make it more difficult for people t o understand a space, t o see objects or people against the reflective surface and t o lip read. Glazed fagades a t ground level, where reflection is likely t o be a significant issue, should be carefully considered.

RefIection Glass, other than mirrored glass, can be reflective in certain conditions, which may be confusing and disorientating for some people. Tinted glass or plain glass against a dark background with light on it, when the lighting levels on either side of the glass are a t

I Reflections in glass can be reduced by: positioning glazing so that it is not seen against a dark background avoiding the use of glass opposite a window having similar lighting levels either side of the glass

r’ This reflection of a path and vegetation in a mirror-glazed building could cause visual confusion

This glazed door and screen appear to lead to an adjacent external space, but are in fact part of an enclosed building entrance. The use of reflective glass can be misleaaing and a potential source of visual confusion

I Glass in Buildings

environment. Increased noise levels will make it more difficult for people t o communicate and t o distinguish sounds that may assist with navigation. Ideally, for ease of communication, areas should be quiet, with minimal reverberation so that specific sounds can be heard clearly.

Shadows from a glazed roof could be mistaken for steps

only using tinted glass in locations where it cannot act as a mirror t o people adjacent t o it minimising reflective surfaces: matt surfaces are preferred Large areas of glass, such as atria roofs and curtain walling, may cause reflections and shadows on floors, particularly if they are light coloured and shiny. If these reflections are heavily patterned due t o the structure and glass framing, they may be confusing and, in some cases where the reflection is striped, could be perceived as steps. Such reflections can be eliminated or reduced by having a matt floor finish and providing shading.

Acoustic environment Glass is a hard material with little inherent acoustic insulation and low absorption characteristics and, when used for walls, ceilings, floors or stairs, may allow the transmission of noise or cause impact sound or reverberation and adversely affect the acoustic

When designing a building with large areas of external glazing (curtain walling, roofdatria) or internal glazed partitions, acoustic insulation against external noise or noise from adjacent areas should be carefully consideredso that the background level of noise is not raised t o unacceptable limits. The insulation provided by glazing is dependent on the mass of the glass, the differences in pane thickness, the cavity width, the gas filling and whether the panes are parallel or not. Special resin or PVB laminated glasses that provide acoustic insulation are available. When glass is used for walls, ceilings or floors some soft, absorbent materials should be incorporated into the area so that noise is absorbed and reverberation time and echo are not excessive. Footfalls on glass floors and stairs will cause impact sound and should either be positioned away from areas where this could be a disturbance, or be designed so that the noise cannot be transmitted t o adjacent areas. Sound insulation of glazing is covered in BS 62624~2005.

Psychological comfort As discussed above, large areas of glazing may cause disorientation and confusion by their transparency and lack of perimeter definition, or by the glare and reflections created.

In addition, where glass is used as a full-height partition or barrier a t height, as a floor, or t o enclose lifts, its transparency and lack of perimeter definition may be particularly disorientating, confusing, or frightening t o some people. To reduce such fear and anxiety, physical protection should be provided t o prevent people getting close t o the glass and being aware of a drop.

Design and specification guidelines

light and ventilation as well as a view out. Windows can range from small porthole apertures in a solid wall t o full-height curtain walling. Full-height glazing is discussed in the section Glass walls and partitions below. This section covers the more traditional window arrangement where framed glazing is set within, for example, a masonry or timber-framed wall.

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The absence of manifestation or a mid-height rail to the glass lift enclosure at an upper level could be disorientating and frightening to some people

Technical guidelines This section covers specific design guidance relevant t o different applications of glass in buildings.

Windows Windows are an essential feature in buildings of every type and provide natural

People like t o have an unobstructed view out of windows when they are standing and seated, and this will affect sill height, the height of transoms and the horizontal position of the window within the reveal. To enable people in a seated position t o benefit from a view, consideration should be given t o providing a lower sill, as long as requirements for safety are met. The glazing line a t the sill, when the window is closed, should be no more than 900mm above floor level and transoms should not be placed between 900mm and lZOOmm, see Figure 5. Other issues covered above that need t o be considered are: any glass in windows below 800mm above floor level should be safety glass or have permanent physical protection (see Human impact resistancelsafety, p9)

4 Transom heights selected to enable view

No transom between 900 and 1200 above floor level Wall or safety glazing complying with BS 6180

I Figure 5 Heights of window transoms to allow view from wheelchair or chair 19

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Glass in Buildings

the position and orientation of windows in relation to internal circulation routes and room functions must be carefully considered to avoid glare

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Glass walls and partitions Glass walls may be external walls, either non-loadbearing curtain walling, or structural load-bearing elements, including fins, plates, and beams, or internal partitions used to increase natural light in deep buildings. They often include glazed doors (see p22). In some cases external glass walls may be sloping, defined as glazing that makes an angle of 15 degrees or more with the vertical. Glass walls may also be constructed of glass blocks, which may be load-bearing. These will let light through while retaining privacy.

Issues covered above that need to be considered are:

Tinted glass walls have been used for small meeting rooms within an open plan office, retaining the integrity of the open plan, but clearly identifying the walls, allowing light into the meeting rooms and providing acoustic privacy

human impact resistance for glazing in a critical location, below 800mm from finished floor level. The exceptions are large areas of glass that are supported on all edges and form part of the fronts to shops, showrooms, offices, factories and public buiIdings visibility and identification by physical features or manifestation - markings for safety and visibility glare, particularly from external glass walls where the sky is the background

I L A glass brick wall lets light into the entrance area

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Contact and collision with this fully-glazed wa are prevented by the structural fins, the handrail and a change in floor surface

Design and specification guidelines

reflection, particularly when tinted glass is used, or where plain glass walls and partitions are seen against a dark background acoustic environment, particularly acoustic insulation from external noise where the external fasade is glass, and reverberation and echo where glass forms internal walls

Glass roofdatria

The glass panels of this fully-glazed building have etched bands to provide manifestation, privacy and some solar shading

Glass roofs and atria are increasingly being used in shopping centres, off ices, hotels, leisure facilities and other public buildings to maximise daylighting, but provide weather protection. Glass roofs can be a source of glare and may create reflections and shadows on other surfaces such as floors and walls. For example, if the floor surface is light coloured and shiny the glass roof may be reflected on it causing confusing patterns or lines from the glazing bars that could be mistakenfor steps. To reduce this, a matt non-reflectivefloor surface should be used and, if necessary, blinds or other solar shading can be provided.

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This glass wall provides a visual link between public and private areas, but the lack of clear manifestation is a potential hazard

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A glazed roof can cause confusing shadows on the interior below it 21

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Glass in Buildings

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Normally, glass roofs are not intended for public access, but if they are, they should be designed as glass floors, see below.

Glazed entrances, doors and screens Many public buildings are now being designed with glazed entranceways and glass doors, allowing more daylight into the building, greater visibility of people entering and leaving the building and visually integrating the external and internal space more closely. Improved visibility into and out of a building entrance is generally considered a good feature, particularly for buildings to which members of the public have access, as it can aid orientation and increase security.

Glazed atria can be used to provide light to several storeys of a deep building. Care must be taken that the glass does not cause glare and reflection

Entrances and entrance lobbies provide a transition zone between external and internal lighting environments. Where substantial glazed elements are incorporated into the design, confusing and distracting reflections may result. This is usually exacerbated in particularly bright conditions when sunlight

Glazed entranceways are increasingly common. They provide a view into the building interior, which can aid orientation and improve security 22

Design and specification guidelines

enters the building directly or is reflected off surrounding surfaces. The use of glass in building entrances and lobbies should be carefully considered to improve visibility, but should not create distracting reflections. The glazed walls forming the entranceway should follow the guidance for walls given above.

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Glass doors should be apparent and distinguishable. When they are part of a fully glazed wall, they should be differentiated from the walls, with the door more prominent. Differentiation can be achieved with the use of door framing, large door handles and, for example, a change in the pattern, size or colour of the manifestation markings.

The presence of glazed doors and screens should be clearly highlighted by manifestation or physical features such as framing. The AD N recommendsthat if glass doors are framed, have a horizontal rail, large handles

These framed, glass doors have clear manifestation and the leading edge is clearly identified by a coloured strip

The entrance doors in this glazed facade are clearly identifiable by their bold framing

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Glass in Buildings

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b These doors into a conservatory are well defined by their substantial framing and horizontal rail

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or push plates, or have visually contrasting opaque strips, at least 25mm wide, a t the top and on both sides of the doors. Manifestation may not be necessary. Glazing that is within 300mm of the edge of a door and is wholly or partially within 1500mm of finished floor level is a critical location, and must either be safety glazing or physically protected from impact. Ideally all glass doors should have protection below 400mm from finished floor level t o prevent damage by wheelchair footrests and pushchairs.

Fully-glazed frameless doors are not recommended as they are not visually apparent and the leading edge can present a hazard when the door is open. If they are used, or where they already exist in buildings, safety and visibility can be improved with the provision of guarding and the addition of highcontrast strips t o the door edges. If hinged frameless doors are used they should be protected by a guarding rail when they are open so that there is no risk of collision with the leading edge. Both sides and the top of the door should visually contrast with its surroundings. This can be achieved by using a high-contrast coloured edging, 25mm wide, permanently fixed t o the door.

Other issues, covered above, that should be considered are glare and reflection. I

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I The presence of these unframed glass doors is identified by the large handles, but these might not be clearly seen against the planted background and surrounding grey surfaces. In addition, the leading edge of the open door is not identified or protected in any way and may present a hazard to some building users

Guards and barriers Guards and barriers are normally required t o restrict the movement of people (or vehicles not covered here as glass is not a suitable material) or t o protect them from a change in level such as the edge of a floor, gallery, balcony, stairs and ramps, parts of a roof t o which people have access and features such as light wells and basements. Barriers are generally needed in non-domestic buildings where there is a change in level greater than 380mm. Guards and barriers are covered by AD K, Section 4 of the Technical Handbook for non-domestic buildings (Scotland) and Part H of the Building Regulations (Northern Ireland). Where guarding is required, and the minimum heights, varies between the different regulations. Further guidance is given in BS 6180:1999 Code of practice for barriers in and around buildings.

Full-heightbarrier

This clearly framed glass balustrade visually links the stairs to the shop and allows users to view the goods on the floor below. The handrail and support posts visually contrast with the background surfaces to highlight the presence of the balustrade Barrier with glass infill panels

Free-standing balustrades differ in that there is no supporting framework. The glass is fixed to the structure along its bottom edge and has a handrail at the top edge. In this case the glass must withstand all the design loads. Such free standing balustrades are often used t o create

Free-standing glass barrier Figure 6 Types of barrier Glass can be used as a component material in guards and barriers, for example, as a stair or landing balustrade, or as a full height barrier/ wall at a level above ground. In balustrades, glass may be used as infill

panels in which all the loads are taken by the main frame (handrail and balusters) and the glass provides no support t o the frame. In this arrangement, the framing members (usually either metal or timber) visually define the position and configuration of the guarding, as long as they provide reasonable visual contrast with the background surfaces. To improve visibility of the infill glass panels, the glass can be tinted or etched so that it too can be visually differentiated from the surrounding surfaces.

This freestanding glass balustrade visually integrates the balcony area with the rest of the station. Although the handrail may not be clearly visible against the background the presence of a barrier is also denoted by a change in floor colour

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Glass in Buildings

Full-height barriers may be formed partially or wholly from glass, and include storey height windows or glass walls in which the glazing is either fully framed or partially supported. Refer t o Glazed entrances, doors and screens. Glass in guarding and barriers must resist

A full-height glass screen, projecting over the

water, is used to visually integrate the external environment with the building. Structural glass fins and a metal floor grille discourage people from getting too close to the glass an open feel or t o minimise obstructions to a view, but may, as a result, create an environment in which some people will feel insecure. The appropriateness of using such a visually open arrangement can depend on the nature of the building or environment in which the balustrade is used. The use of obscured glass or tinted glass can increase the perception of 'solidity' t o the balustrade.

human impact. Barriers should not have any sharp edges or projections and the edges of all glazing panels should be properly protected and identified by a visually contrasting strip. Consider the use of tinted or obscured glass in locations where the view of a change in level may cause anxiety or disorientation. A change in colour or texture of the floor surface, or a low rail, can help t o identify the presence of a barrier and if heavily textured may prevent people getting too close.

Glass floors including bridge decks and accessible roofs Glass floors, normally consisting of panes of glass in a steel frame, are becoming increasingly popular in prestige buildings including retail, offices, restaurants and other public buildings. Glazed floors may also consist of glass blocks, and glass blocks or lenses may be incorporated into floors of other materials, normally concrete.

Glass floors, bridge decks and roofs may be used t o allow light into an area underneath or above, t o protect artefacts such as mosaics and archaeological remains while allowing them t o be visible, or simply as an architectural feature t o give the appearance of lightness.

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The edges of this freestandingglass balustrade are protected with a steel edging 26

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The use of glass as a floor surface is likely t o be a source of anxiety for many people, even if the glass is translucent or opaque. Some people may not think that the glass is sufficiently strong t o bear their weight and many will perceive the glass t o be slippery even if it has an appropriate slip resistant surface. Glazed floors may also cause visual confusion, disorientation or fear, particularly if there is a perceived difference in height. Similarly, the transition from an opaque t o a transparent surface may create a problem for some people.

Design and specification guidelines

Wherever a glazed floor, deck or roof is incorporated into a building or environment, consideration should be given t o the provision of an alternative route or area of conventional 'solid' construction t o give building users choice and flexibility. The provision of handrails or guarding may be appropriate t o the perimeter of some glass floors or viewing areas, such as archaeological remains, and will provide an increased perception of safety for many people. Surface treatment that reduces the transparency of the glass may help t o reduce the potential for visual confusion and fear. Where glass is used for flooring (floors, bridge decks, accessible roofs) or for stair treads it must provide adequate slip resistance in both dry and wet conditions so that it does not present a hazard t o users. Ordinary glass is extremely slippery when wet. An acceptable level of slip resistance can be achieved by surface treatment: a profiled surface and/or a fritted or sandblasted finish t o the glass, available in a wide variety of patterns, with or without a maintenance coating. Fritting and sandblasting does cause the glass t o loose some of its transparency, but this may be an advantage when people can look up from below. Particular care needs t o be taken where a glass floor is adjacent t o other floor finishes. To avoid stumbling and falls, the two different surfaces should not have significantly different frictional resistances. The slip resistance of floor

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The sandblasted glass floor finish of this slightly sloping glass bridge provides satisfactory slip resistance and makes the glass less transparent. It has good contrast with, and similar frictional resistance to, the adjacent stone floor finish surfaces is covered in BS 5395-1:2000 Stairs, ladders and walkways. Code of practice for the design, construction and maintenance of straight stairs and winders and the Specifiers' Handbooks for Inclusive Design: Internal Floor Finishes. If the glass floor has a maintenance coating, precautions should be taken t o prevent spillage of substances likely t o damage the coating, and care must be taken that it is cleaned correctly with a non-abrasive, non-acidic cleaning agent, so that the integrity and performance of the coating is not affected. The coating will need t o be renewed a t regular intervals, depending on the amount of traffic.

In some special situations, for example, dance floors, a very high slip resistance may be

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Fritted glass provides adequate slip resistance to this glass floor, while still allowing a view of what is below

Pedestrians walking on a glass roof 27

undesirable as it may result in excessive binding and restrict movement. In such locations precautions should be taken t o prevent liquid spillage, for example by an operation policy not t o allow bottles or drinks t o be taken into the area. Footfalls on glass floors will generate impact noise, which will increasethe background noise level and may be transmitted t o other areas. Being a hard surface it will reflect sound and thus increase reverberationtimes and echo (see Acoustic environment, pl8). Where a glass floor is used, soft materials should be used in other elements or furnishings in the area t o achieve an acceptable acoustic environment. Where glass is used for an accessible roof, laid t o falls for drainage purposes, increased slip resistance will be required depending on the fall.

Glass stairs Glass staircases are normally designed t o be an architectural feature in a building, and be visually light in appearance. They are often freestanding.

Glass stairs should meet the requirements of the relevant building regulations, as should stairs constructed of any other material. Open risers should not be used as looking through them may cause some people t o feel insecure. They can also be dangerous t o small children and present a potential trip hazard t o many building users. Solid risers with square or chamfered nosings can be achieved with careful detailing while maintaining the overall aesthetic of the stair.

The transparency of glass treads is likely to be reduced by surface treatment t o increase slip resistance, but may still cause disorientation, particularly if there are bright light sources below the stairs. The careful selection and positioning of light sources both above and below the stairs, other building features, furniture or displays all play a part in improving the visibility and perception of the stair.

These glass stairs have open risers and are poorly defined with no contrasting nosings. The striped pattern on the glass is likely to be confusing to many building users The treads of glass staircases must be slip resistant (see Glass floors, p26) and the treatment must not cause visual confusion. Each step should have visually contrasting slip resistant nosings, as recommended in BS 8300:2001. These nosings can be provided by timber or metal framing t o the glass tread or etching. Footfalls on glass treads are likely t o be significant and this should be considered in the context of the building or environment in which the glass stair is situated.

Glass lifts Glass lifts are being increasingly installed in buildings, particularly offices, shopping centres, hotels and public buildings. They may be framed, usually with stainless steel, or unframed.

The glass enclosures and walls of lifts must be considered as full height glass barriers (see above). A particular risk for young children, identified by the Health and Safety Executive (HSE), is

getting their fingers caught in the horizontal gap between the door and the architrave/jamb when the landing door opens. Doors with fully flush surfaces may cause squeezing/pinching injuries or, if the glass panel is recessed into a metal frame, cuts and lacerations may occur. HSE recommends the use of metal doors for new glass lifts, particularly where young children will be using the lift. Glass doors are not, in fact, included in the recommendations in BS EN 81: Parts 1 and 2. Other safety improvements that can be considered for both new and existing glass lifts are:

doors fully flush on their exposed surfaces clearance between doors and their architraves t o be less than 6mm, if possible provision of bristle type defector devices over full height of architraves t o prevent access t o the gap between the door and the architrave use of opaque glass over a t least the area likely t o be used as a 'window' by small children automatic door opening speeds and forces reduced t o a minimum

Glass lifts on the outside of tall buildings may cause confusion, disorientation or fear for some people automatic door opening delayed until the lift car has stopped level with the landing audio-visual warnings t o advise people t o stand away from the doors supervision of lifts by staff

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These doors to a glass lift are clearly defined with solid frames, manifestation different from that on the adjacent glass panels and a change in floor finish

Thisglass lift in a shopping centre allows views of the different levels. The coloured framing and the handrail help to identify the perimeter of the lift car and the latter provides protection to the glass. However, there is no protection for the glass from buggies and wheelchair footrests at lift floor level

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Glass in Buildings

Glass lifts, particularly where they are not enclosed and are on the outside of a building or in an atrium, may cause confusion, disorientation or fear, especially when they are moving or at height.

Disorientation and fear can be lessened by reducing the transparency of the lower part of the glass walls by treating the glass, applying a suitable film, or adding handrails. Accessibility t o lifts is covered by BS EN 8170:2003.

Glass screens at counters Glass screens a t counters where there is a need for visibility between staff and customers, are usually provided for security purposes, for example, in banks and post-offices, and where there is a risk t o the safety of staff and security of goods. They may also be used t o provide acoustic privacy for activities on the staff-side of the screen, for example, where a counter is positioned a t one side of an open plan off ice, or for protecting staff from contact with customersklients for hygiene, health or other reasons, for example in a hospital.

The use of glazed screens a t counters can impair communications between staff and customers and, as a result, should only be used where absolutely necessary. Many people find lip reading through glass difficult. e

Glass screens a t counters must be unobstructed and free of reflections so that the person on the opposite side (either staff or customer) is clearly visible. e The position and design of the screen, the background behind it, the glass specified, and the level and direction of natural and artificial lighting should be designed so that the faces of the people either side of the screen can be clearly seen. e Non-reflective glass should be used, and in most cases security glass will be required. e Any freestanding edges of glazed screens should be identified by a strip visually contrasting it with the surroundings against which it is seen.

Due to the difference in lighting levels, this glass screen is acting as a mirror, causing confusing reflections The provision of speech and hearing enhancement systems should be considered wherever the provision of a glazed screen is likely t o impair communications between staff and customer. If provided these should be clearly signed, staff should be trained in their use and they should be regularly checked t o ensure that they are fully operational.

Vision panels In buildings other than dwellings, the Building Regulations require that, normally, entrance doors, lobby doors and internal doors across corridors and side panels wider than 450mm have vision panels towards the leading edge of the door t o enable people t o see and be seen from either side of the door. This is essentially a safety function, although also serves t o provide a visual link between adjacent spaces which can aid orientation and navigation around a building. Vision panels may also be provided t o other doors in a building, for example, room doors and side panels. Here, vision panels serve an additional function by enabling building

Design and specification guidelines

Tall stature

Small stature

Figure 7 Minimum zones of visibility users t o see whether a room is occupied. This can be particularly beneficial for people with a hearing impairment who may not be able t o hear the sound of voices on the other side of a door before entering a room. Where vision panels are provided t o room doors or side panels, but where there are occasions where complete privacy is required, blinds or louvres can be incorporated into the door or screen design. These should not be used on entrance doors or doors on circulation routes where visibility is required a t all times. AD M and BS 8300:2001 recommend a minimum zone of visibility for a single vision panel between 500mm and 1500mm from the floor. Where a door has a horizontal rail, there should be a t least two vision panels, one between 500mm and 800mm and the other between 1150mm and 1500mm above the floor, see Figure 7. More than two vision panels can be provided, as long as the zones are within the glazed area. In Scotland (Technical Handbook: Nondomestic clause 4.1.5) and Northern Ireland (Technical Booklet Part H Section 6)the minimum requirements for the zone of visibility are from a height not more than 900mm t o a t least 1500mm above floor level. However, the dimensional guidance in AD M and BS 8300:2001 provides improved visibility for people a t a range of eye levels and is recommended t o be followed wherever possible.

Vision panels may be omitted on entrance doors if it can be justified in the access

statement, for example, for security reasons. For internal doors, BS 8300:2001 states that the vision panels may be smaller than the minimum size or omitted where the door leads t o a space that requires t o be darkened for its function, for example in cinemas and auditoria. At least part of the glass in correctly designed vision panels is in a critical location and should therefore be safety glass, unless the width of the panel(s) is less than 250mm and the area of each does not exceed 0.5m2 (measured between the glazing beads or similar fixings). In this case, annealed glass of at least 6mm nominal thickness may be used, or, in the case of traditional leaded or copper lights, 4mm glass is acceptable if fire resistance is not a factor. If it is proposed t o provide vision panels in existing door leaves, or if existing vision panels are t o be increased in size, care must be taken t o ensure that the fire resistance of the door is not compromised. The glass and its method of installation into the door should be selected accordingly. The advice of a qualified and competent professional should be sought in these circumstances.

Rooflights Rooflights are normally used as a means of letting daylight and ventilation into the space below, creating a brighter, safer and more pleasant environment, with less need for artificial lighting systems. Rooflights can be incorporated into either a pitched or a flat roof. In a pitched roof, in-plane 31

rooflights are the most common, and are normally made of plastic materials rather than glass. In flat roofs, rooflights can be sloping, curved or horizontal glazing, glass or plastic, standing a t least 150mm proud of the roof surface, but may also be glass lenses flush with the roof surface. As with any overhead glazing there is a risk t o people below from the glass breaking and falling down. To minimise this risk, and the risk of people falling through a rooflight, new rooflights should always be rated as ‘non-fragile, as defined in the Advisory Committee for Roofwork (ACR) Materials Standard ACR [M]001:2005 Test for non-fragility of profiled sheeted roof assemblies, which is considered applicable t o all roofing systems. The design of rooflights in relation t o their safety in use is covered by BS 8213-1:2004 Windows doors and rooflights. Design for safety in use and during cleaning of windows, including door-height windows and roof windows. Code of practice. Rooflights that are raised above the surface of the roof are generally considered t o be safer than in-plane rooflights as they are more visible and are more difficult t o stand on, but they can present a trip hazard with the attendant risk of falling onto or through them. Raised rooflights on a roof accessible t o the public should be protected by barriers.

On flat roofs accessible t o the public, where rooflights in the form of lenses flush with their surroundings are larger than 1OOmm by 100mm, they should be considered in the same way as glass floors and have adequate slip resistance, including when wet (see Noors above). Other issues, covered above, that need t o be considered are glare and reflection.

Display cases Display cases are used in museums and galleries t o protect artefacts. They also usually have t o provide a stable micro-climate, protection from ultraviolet (UV) light, and security against damage and theft. Inappropriately designed display cases can limit the view of some people, for example children and people of short stature. To allow a range of users t o view displays it is recommended that the base of a display case is a t a maximum height of 760mm above finished floor level. To enable wheelchair users t o approach close t o the display case, space should be provided underneath the case, with minimum dimensions of 700mm high, 500mm deep and 800mm wide.

Display cases should enable a wheelchair user to bring the arms of their wheelchair to the front of the case and provide clear knee space underneath

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Figure 8 Display cases 32

Design and specification guidelines

Display cases should not be more than 5OOmm from front t o back, unless they can be viewed from both sides. Where display cases have glazing down t o the floor they should either have a kick plate or have protection up t o 400mm above finished floor level t o prevent damage from wheelchair footrests and buggies. Freestanding display cases may be a serious hazard if they are not clearly visible, increasing the risk of collision and damage t o the case. This is most likely t o occur when the glass is not framed. Glass used for display cases should, as a minimum, be safety glass. In most cases security glass will be required, which will more than satisfy the safety requirements. Display cases should either be framed or have visual identification. For high security applications framed cases are recommended, with 25-30mm edge cover t o the glazing. Visual identification can be achieved by contrasting plinths, the positioning and design of the interpretive material, or manifestation on the glass, but care must be taken that these do not obscure the visibility of the displays or create visual confusion. Unframed edges of glass and corners should be identified by a visually contrasting strip.

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A display case well defined by its plinth and framing

Display cases are susceptible t o glare and reflection from windows and artificial lighting, which may reduce the visibility of the contents. BS 8300:2001 recommends the use of non-reflective glass t o eliminate glare and reflections. These can also be minimised by:

the positioning of the display cases in relation to windows not having display cases against a dark background or lined with a dark finish, so that they act as mirrors angling the glass lighting within the case, but care will be needed t o avoid heat build-up or light damage t o exhibits

Well-placed interpretive material on a contrasting background can be used to help identij, the glass display case 33

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Glass in Buildings

Conservatories Non-domestic COnSerVatOrieS should follow the guidance above for windows, glazed walls, doors and roofs as appropriate.

Shower screens Any glass forming part of a bath or shower screen is a potential hazard and BS 626242005 recommends that it should be classified as safety glass, see Appendices. Shower enclosures should also conform t o BS EN 14428:2004 Shower enclosures. Functional requirements and test methods.

Mirrors Mirrors are only considered in this guidance where they form elements of a building or are specifically recommended in BS 8300:2001, for example in l i f t s and WCs.

Mirrored walls Mirrored walls may be used t o create the illusion of space in small rooms, for example in restaurants, or t o reflect an interesting structure. They can be a potential hazard t o many building users as they are unlikely t o be

perceived as a solid surface and may greatly distort a person's perception of the space, indisorientation and confusion. Their use must be considered with great care particularly mirrors opposite other mirrors. If mirrored walls are used, they should either be protected by a physical barrier, such as a railing or furniture, or be visually identified by manifestation so that there is no risk of people trying to walk through them. They should be safety glass. Other issues, covered above, that need t o be considered, are: glare, reflection and acoustic environment.

Mirrors in lifis In l i f t s that are accessible t o wheelchair users, the provision of a half-height mirror is recommended, with the lower edge 900mm above floor level on the internal side opposite the door. The mirror enables a wheelchair user t o see behind them when reversing out of the lift in situations when the lift car is too small t o enable the wheelchair user to turn through 180 degrees. Full-height mirrors should be avoided in lifts as they may give the illusion that the lift car is a through-corridor.

Mirrors can be used effectively to make a space appear larger, but they should be used carefully to reduce the potential for visual confusion. The mirror wall on this narrow balcony reflects the rest of the hall and is well protected and identified by the tables

Design and specification guidelines

Mirrors in WCs and bathrooms

A full-height mirror on the rear wall of a lift car may be perceived by some people as a larger room or corridor. It can also be disconcerting when entering a lift with a full-height mirror, as you can appear to be moving directly towards another person

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For accessible WC compartments, bath and shower rooms, BS 8300:2001 recommends that a mirror with its bottom edge set a t 600mm above ffl and a minimum height of 1000mm should be located away from the wash basin, so that it can be used by both ambulant disabled people and wheelchair users. The position selected should consider the dignity of the user. Where a mirror is located above a wash basin it should either be fixed as closely as possible t o the top of the basin and extend to 1,600mm above finished floor level or tilted forward, which may enable a smaller mirror to be used. Large expanses of mirror should be avoided as they can distort the perception of space. Full-length mirrors should not extend t o floor level as they may be perceived as a wall opening.

Glass signs Glass is sometimes used as a backing plate for signage. Its effectiveness will be dependent on i t s positioning and lighting, and the visual contrast between the text and the background against which it is seen.

Glass signage should be designed and positioned where it will have good visual contrast between the text and the background, and will not be subject t o glare or reflections. If mounted on a wall, glass signs should be fixed and lit so that the text and images do not cast shadows behind.

Historic buiIdings

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In lifts that are too small to enable a wheelchair to turn, a half-height mirror on the rear wall is recommended to enable a wheelchair user to see behind as they reverse

There is unlikely t o be extensive use of glass in the existing fabric of historic buildings: it is likely to be restricted t o windows. Any changes t o the existing glass, or the addition of new glazing, are likely t o require permissions such as Listed Building Consent (LBC), and the local planning authority and conservation officer should be consulted as early as possible. 35

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Glass in Buildings

r This glass sign seen against a complex background does not show up well

I A glazed barrier for a new ramp in an historic building minimises its visual impact on the existing fabric

To maintain the character of the building, it may be necessary to replace existing glass with similar glass rather than that which would be required in a new building, for example safety glass in French windows. Similarly, it might not be appropriate to add vision panels to existing doors. Any shortcomings in the physical

a,

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4 "

A glass floor, clear at the perimeter, allows the

The same sign against a plain background is clearly visible 36

existing fabric to be viewed through the new addition

Design and specification guidelines

requirements of the glass can normally be overcome by temporary solutions, such as movable barriers, or management solutions. Glass can be advantageously used in alterations or addition t o historic buildings t o improve access. It can be designed t o be unobtrusive and have minimum impact due t o i t s transparency, while allowing the existing structure t o remain clearly visible.

This glass lift enables the existing fabric to be seen from the lift car and minimises the visual impact of the new lift structure

37

I

Building management Cleaning and maintenance Glazing needs t o be cleaned regularly t o maintain its performance and appearance. Cleaning is particularly important: when good visibility through the glass is needed, for example for screens on counters and vision panels where dirt or other contaminants could affect the slip resistance of the glass, for example rooflights, glass floors, and stairs t o ensure that manifestation on glazing remains in place and is clearly visible in all lighting conditions Under the CDM Regulations, designers are responsible for providing safe access for cleaning and maintenance. Consideration should also be given t o any possible inconvenience t o the building occupants. BS 6262-1:2005 states that the selection and design of glazing should incorporate provisions for cleaning, care and replacement. Care should be taken that the cleaning methods and materials used do not damage the glass, for example scratch it, or damage the surface finish, which will affect its performance.

4

Normally warm water with a neutral detergent applied with a cloth, mop or sponge will be sufficient. Abrasives should not be used. Glass floors and stairs should be left dry after cleaning, or barriers and warning signs should be used t o prevent people walking on the wet floor.

Inspection Glass, its fixings and seals should be inspected regularly t o assess for damage or deterioration of any of the components that may affect safety or performance.

Where external or internal screening is provided t o reduce glare this should be regularly inspected and cleaned t o ensure that it continues t o provide effective shading.

Repair and replacement Any glass failures, breakages or damage must be dealt with immediately as the damaged glazing and glass fragments can present an additional hazard that could result in injury. Similarly any fixings or seals that have deteriorated or broken should be repaired immediat e Iy.

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Case studies Paddington Station, London The new concourse a t Paddington Station, called The Lawn, uses glass extensively t o provide a light, airy structure providing station check-in facilities and a waiting area, and a new retail court. It is physically separated, but visually integrated through a glass screen with the station, originally designed by Brunel. The architect for the new concourse, completed in 1999, was Nicholas Grimshaw and Partners, who drew on their experience of using glass a t Waterloo Station. Paddington Station is a Grade I listed building and therefore a high proportion of the design and specification were subject t o consultation and approval from English Heritage, other statutory authorities and historic societies, as well as Westminster City Council.

One of the striking features of the new building is the glazed roof, which is based on an early 19th century ridge and furrow system sometimes used by Brunel. Twelve steel trusses spanning 20 metres are covered in toughened laminated glass. Although much of the roof is overshadowed, solar shading is required and has been provided for by external aluminium louvres. The glazed screen, 50 metres long, between the main concourse and the retail area is supported on slender, stainless steel columns, t o maximise the integration of the two spaces and the view of the listed station. Manifestation on this glazed screen, by large, dark blue, round-ended rectangles generally contrasts well visually with the busy background against which it is seen. The bottom of the screen is protected on either side by a low rail, t o prevent damage from buggies, wheelchairs and luggage, and protecting airheating grilles.

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The new concourse is separated from the main station but visually integrated with it by a double-storey-height glazed screen 41

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Glass in Buildings

The ridge and furrow glazed roof has external aluminium louvres to provide solar shading Sliding, fully-glazed doors within the screen are easily identifiable by their framing and manifestation. Stainless steel guard rails are provided either side of the doors. The leading edges of the doors have a dark blue strip t o provide visual contrast and protect them. The three floors of retail facilities, with intermediate mezzanines, are accessed by a steel-framed glazed lift, escalators and stairs.

Sliding glazed doors are identifiable by their framing, manifestation and colour identification of the leading edge. They are protected on either side by glazed barriers The mezzanines are linked t o one another by glass bridges and walkways. The balustradest o the stairs, escalators and higher levels are freestanding glass barriers, with a stainless steel handrail a t the same level as the top of the glass, cantilevered on brackets bolted t o the top of the glass. The top edge of the glass is finished with a stainless steel protective edging, although in some cases this has come off. The edges of the glass a t the corners of the baIustrades a re similarly protected. The glass bridges and walkways are composed of steel-framed glass panels with an etched surface t o provide slip resistance. In some areas these are lit from underneath with either tungsten or blue fluorescent lighting and because of the dimensions of the panels, these could be mistaken for steps in some areas.

-

Dark blue manifestation is not always visible against the different backgrounds. The bottom of the glazed screed is protected from damage by a low rail on either side 42

Glass bridges and walkways link the mezzanine and first floor levels

Case studies

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a

dark and lacking in interest. The objective of the new design by Herzog de Meuron was therefore t o create a bright and transparent shop which, as well as providing additional retail space, would bring new interest t o the riverside entrance. The design concept was for the shop t o be a 'glass crystal' with faceted glass walls and a brightly lit interior. This required the glass t o be marked with only minimal manifestation.

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Manifestation providing some privacy while maintaining the visual integration

To enable light from the roof t o penetrate t o the lower levels, the upper circulation floors have flush glass lenses set into them, with a coffered ceiling below, and some are also lit from beneath. The effectiveness of these for transmitting light is dependent on their cleanliness on both the upper and lower surface. Many of the retail spaces have floor-to-ceiling glazing, and folding or sliding fully-glazed doors, so that they are visually and physically integrated into the whole area. A variety of manifestation designs have been used, including some extending down t o floor level, which obscures the view while still maintaining the overall philosophy of visual integration.

Glass with minimal manifestation Tate Modern - new glass shop Before the construction of the new shop, entry t o Tate Modern from the Thames riverside frontage on the north side of the building was

Problems had arisen previously a t other parts of Tate Modern because of inadequate manifestation, particularly a t the lower floor of the Turbine Hall where children had bumped into glazing which lacked manifestation at the lower level, and adults had done the same where there were gaps in the manifestation a t eye level. In addition, a combination of inadequate manifestation, poor illumination and reflections on the glazing had caused problems and confusion a t other areas of the building. An examination of the existing manifestation a t Tate Modern showed that the conditions varied considerably and were influenced by a combination of the following: e

e

e

e

manifestation - where the manifestation consisted of continuous rows of grey film, this was generally reasonably visible. In parts of the Turbine Hall, the only manifestation was grey lettering, and problems occurred where there were gaps in the lettering illumination - the visibility of the manifestation varied greatly, depending on whether the manifestation was lit from the front or the rear background -the visibility of identical patterns of manifestation varied according t o the background, particularly where this lacked colour reflections - lights reflected on the glass could be very confusing, making it difficult t o assess the distance t o the glazing and t o know where it was safe t o walk flooring -the problems of invisible glazing a t Tate Modern were aggravated by the fact that in some areas the timber flooring was continuous on both sides of the glass so that 43

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Glass in Buildings

some people walked straight ahead and hurt themselves by bumping into the glass In complete contrast t o these observations, no problems were reported a t the glass around the side of an escalator where the full height glazing had no manifestation. The reason for this was that the space around the escalator was brightly illuminated, it was visually apparent that the floor stopped at the line of the glass and someone with a cane would encounter the glass safely by touch. The success of this feature indicates, controversially, that it may be safe t o install new glass lifts without any manifestation t o the surrounding enclosure. As always, it is necessary t o monitor unusual designs and t o take remedial action if necessary. The design of the new glass shop in consultation with access consultants, David Bonnett Associates, took account of all these observations, seeking t o use only the minimal amount of manifestation for safety while achieving the required transparency for the shop. Because it was impossible a t design stage t o predict the visibility of the glazing and the

way in which this would be influenced by the lighting, it was agreed not t o decide on the manifestation until these installations were complete. Various arrangements for the manifestation were then tested in-situ before the access statement was completed. The completed installation was then inspected and approved by the Building Inspector. The completed design included the following features: glass panels, tilted a t varying angles, with silicon joints at the corners; no attempt was made t o improve the visibility of these corner joints because the silicon joint is always seen as a dark line the glass doors have no manifestation and, with the adjacent security panels, the location of the doors within the glazed screens is readily identifiable; metal brackets, which protect the external corners a t floor level, help t o define the line of the glazing the floor finish inside that shop is light in colour, brightly illuminated and contrasts with the surrounding floor surfaces, so that

The faceted glass walls with silicon joints am protected at ground level at the corners by low metal window 44

Case studies

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.$

The entrance doors are clearly identifiable by their dark metal framing

no one is likely t o assume that they can walk through the line of the glazing inside the shop, the illumination is bright, but without glare, and the faceted ceiling helps t o keep the space quiet

the manifestation on the glass consists of grey translucent dots, 55mm in diameter and spaced a t approximately 155mm centres, a t heights of about 900mm and 1500mm (as recommended in AD M). This

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The brightly-coloured floor in the shop contrasts visually with the dark floor externally, and clearly identifies the line of the glazed walls 45

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3ass in Buildings

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B

The visibility of the manifestation varies with the backgroundand lighting, but is more visible when one is nearer to the glass manifestation can be difficult t o see in photographs or when standing still but becomes more visible as one approaches the glass, when the manifestation is seen against a changing background the modular shop fittings, of translucent grey polypropylene and suitable for rearrangement in many combinations, allow all the colours t o be provided by the objects on display Because it was recognised that, with such minimal manifestation, the glass walls of the shop could be hazardous for some people, the use of the shop was monitored in case more manifestation needed t o be added. Since the new shop was opened in April 2005, no problems have been reported.

Dulwich Picture Gallery was designed by Sir John Soane in 1811. The new glazed walkway designed by Rick Mather, completed a t the Dulwich Picture Gallery in 2000, has less 46

manifestation than would normally be recommendedbut appears t o be very successful and t o have caused few problems for people with impaired vision because of the carefully considered details. Seen from inside, the full-height glazing has only one line of manifestation, a t a height of about 1200mm above ground level. The bottom of the glazing is marked externally with rows of round stones which show clearly as a very visible border t o the circulation route. Anyone with a cane is likely t o find the line of the glazing, and most partially sighted people will see the pattern of the line of stones. An additional feature of the glazing is that, when seen from the outside, the glass wall usually has no reflections. The reason for this is that glass panels in the roof of the walkway illuminate the rear wall, causing the external glass t o be fully transparent. The lines of stones are an effective and aesthetically satisfactory solution, preventing anyone from walking into the glass and the new extension is a subtle and admirable extension t o the original building.

Case studies

L

Externally the glazed walls to the extension are protected by the structural elements and a broad band of round, white pebbles

Minimal manifestation on the glazing to the new walkway is complemented by the edging of large, round, white stones externally, which clearly define the edge of the circulation route 47

Appendices Types of glass Annealed glass Annealed glass is the most common form of glass used in single and composite glazing. Standard annealed glass breaks relatively easily and fractures into potentially lethal shards or splinters with sharp edges. Laminated glass Laminated glass consists of two or more sheets of glass bonded together with one or more layers of polyvinyl butyl (PVB), resin or polycarbonate sheets. PVB laminated glass is the most common. When it is impacted, broken fragments of glass remain bonded t o the interlayer sheet(s) and there is no risk of injury from flying glass fragments. The interlayer absorbs impact energy, reducing the risk of penetrating the glass. Additional benefits are reduced sound transmittance, particularly a t higher frequencies and reduced ultra-violet radiation transmittance.

Resin laminated glass is used mainly for decorative and acoustic applications, for laminating glass with a heavily textured or patterned surface or for laminating thick toughened glass. Not all resin laminates meet the requirements for safety glass and they do not provide protection against ultra-violet radiation. Glass laminated with polycarbonate sheets is used for some high security glass.

Toughened glass (or fully tempered glass) Toughened glass is produced by exposing sheet glass t o high temperatures followed by rapid cooling. Toughened glass breaks by disintegrating into small fragments with dulled edges that are unlikely t o cause serious injury. It is four t o five times stronger than annealed glass. Toughened glass cannot be cut or shaped after manufacture and therefore must be preprepared.

Wired glass (or Georgian wired glass) Wired glass has a grid of steel wire mesh embedded within the glass, which is intended t o hold the glass in place if it is cracked or broken. The glass breaks in almost the same way as ordinary glass into sharp fragments. There are two types of wired glass, with different wire thicknesses. Glass with 0.42mm wire mesh is used for standard fire-resistant glazing. Glass with wire mesh of 0.7mm thickness or greater can be used as safety glass in some situations, such as sloping/overhead glazing and low-level glazing. Security glass Security glass includes anti-bandit, bullet resistant and explosion resistant glass. Heat strengthened glass (or semi-tempered glass) Heat strengthened glass is produced in a similar way t o toughened glass, but due t o different cooling rates, is only one and a half t o two times stronger than annealed glass. It shatters in a similar fashion t o annealed glass and therefore cannot be classified as safety glass. Coated glass Coatings on glass are used t o reduce solar gain within a building through increased reflection and absorption, or t o reduce the surface emissivity and increase the thermal insulation of composite glazing. The coating does not affect the mechanical properties of the glass. Specialist glasses In addition t o safety and security glazing, glass can also be manufactured or treated t o provide specific properties: fire resistance thermal insulation solar control - heat gain, glare acoustic insulation vision control - privacy decorative surfaces self cleaning glass 49

'intelligent' glass - glass that can automatically or manually change i t s properties under different environmental conditions, including letting more or less light and heat through it, changing from transparent t o opaque, or providing heatable glass

Adhesive backed polymeric films Plastic films, made from polyester, polypropylene and polyvinyl chloride (PVC), and applied t o the surface of the glass with an adhesive, are used for solar control, glare, visual privacy, appearance, explosion resistance or human impact safety. With regard t o the latter, the film does not increase the strength of the glass but, by holding the glass together in a manner similar t o laminated glass, can increase the impact resistance significantly depending on the film type.

Legislation Building Regulations England and Wales In England and Wales, building design and construction is governed by The Building Regulations 2000. These regulations comprise a series of requirements for specific purposes: health and safety, energy conservation, prevention of contamination of water and the welfare and convenience of persons in or about buildings. Part M - Part M of the regulations sets minimum legal standards for access and use of buildings by all building users, including disabled people. The requirement in Part M (for non-domestic buildings) is simply that: Access and use 'Reasonable provision shall be made for people to gain access to and use the building and its facilities.'

This does not apply t o any part of a building that is used solely t o enable the building or any service or fitting within the building t o be inspected, repaired or maintained.

Access to extensions to buildings 'Suitable independent access shall be provided to the extension where reasonably practicable.'

This does not apply where suitable access t o the extension is provided throughout the building that is extended. Sanitary conveniences in extensions to buildings 'If sanitary conveniences are provided in any building that is to be extended, reasonable provision shall be made within the extension for sanitary conveniences. '

This does not apply where there is reasonable provision for sanitary conveniences elsewhere in the building that can be accessed by building users. The regulation avoids specific reference to, and a definition of, disabled people. This inclusive approach means that buildings and their facilities should be accessible and usable by all people who use buildings - including parents with children, older people and disabled people. Previously, Part M covered new buildings and extensions t o existing buildings. The 2004 revision brings Part M into line with other parts of the Building Regulations by extending its scope t o include alterations t o existing buildings and certain changes of use. Approved Document M - Building Regulations are supported by 'Approved Documents' which give practical guidance with respect t o the regulations. While their use is not mandatory and the requirementsof regulationscan be met in other ways - Approved Documents are used as a benchmark by local authorities and approved inspectors. Approved Document M 2004 Edition (AD M) offers technical guidance on providing access t o and within buildings.

Scotland In Scotland, building design and construction is governed by a new building standards system, which came into force in May 2005. The Building (Scotland) Act 2003 gives Scottish Ministers the power t o make building regulations, which are administered by the

Appendices

Scottish Building Standards Agency (SBSA), an executive agency of the Scottish Executive. The Building Standards are supported by two new Technical Handbooks: a Domestic Handbook and a Non-domestic Handbook. The Handbooks provide guidance on achieving the standards set in the Building (Scotland) Regulations 2004. Access requirements are integrated into the Technical Handbooks, as they were in the previous Technical Standards.

Northern Ireland In Northern Ireland, Part R of the Building Regulations (NI) covers Access and Facilities for Disabled People, and is supported by Technical Booklet R:2000.

DisabiIity Discrimination Acts 1995and2005 The Disability Discrimination Act 1995 introduced new measures t o prevent discrimination against disabled people. In addition t o granting new rights t o disabled people, the Act also placed duties on, among others, employers (Part 2), providers of goods, facilities and services (Part 3) and education providers (Part 4). The original Act has been amended by the Disability Discrimination Act 2005 (DDA 2005). The DDA 2005 broadens the definition of disability and introduces further measures t o prevent discrimination. The principal amendments relate t o the definition of disability (Part 1) and in Parts 2 and 3 of the Act. The main thrust of the legislation is t o improve access for disabled people t o employment, education and services. While the DDA does not directly require accessible environments t o be provided for disabled people, either in their place of work or for access t o goods, facilities, or services (for example in shops, restaurants or offices t o which the public have access), duties under the Act include the requirement to consider barriers created by physical features of buildings and t o make adjustments in certain circumstances.

The Act defines a disabled person as 'someone who has a physical or mental impairment which has a substantial and long-term adverse effect on his or her ability t o carry out normal day-today activities'. Discrimination occurs where without justification, and for a reason that relates t o the disabled person's disability, a disabled person is treated less favourably than others t o whom the reason does not or would not apply. Discrimination may also occur when there is a duty t o make a reasonable adjustment and any failure t o meet that duty cannot be justified. Each Part of the DDA is supported by one or more Codes of Practice, which give guidance on how t o meet duties under the Act. While Codes of Practice neither impose legal obligations nor are authoritative statements of the law, they may be referred t o in any legal proceedings pursued under the Act. Building designers, while not legally required t o respond t o the DDA, should anticipate the requirements of the Act by presuming that employees, students and customers will fit the definition of 'disabled person' under the Act, and design buildings accordingly. Those commissioning new buildings or adaptations t o existing buildings should consider the implications of the DDA in terms of their ability t o employ and offer services t o disabled people on an equal basis. The DDA applies t o the whole of the UK, including (with modifications) Northern Ireland.

DDA Part 2: Employment Employers have a duty not t o treat disabled people less favourably than others for a reason relating t o their disability, unless this can be justified, and t o make adjustments t o assist disabled employees or applicants for employment. This may involve changing physical features of the premises if these put a disabled person a t a substantial disadvantage in comparison with persons who are not disabled. The duty of provision of a reasonable adjustment is triggered when an individual disabled person applies for a job, is employed or it becomes apparent that an 51

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existing employee requires some form of adjustment: there is no general or anticipatory duty under Part 2 t o make provision for disabled people. Duties in Part 2 of the DDA covering employers were introduced in December 1996 and have subsequently been amended under the Equal Treatment Directive, which implements obligations placed by the European Union on the UK in relation t o disability discrimination. The Directive removed the existing exemption for small employers so that the Part 2 duties relate t o all employers. The Directive also changed the relationship between Building Regulations and Part 2 of the DDA.

DDA Part 3: Service provision Part 3 of the DDA places duties on those providing goods, facilities or services t o the public ('service providers') and those selling, letting or managing premises. The Act makes it unlawful for service providers, landlords and other persons t o discriminate against disabled people in certain circumstances.

The DDA 2005 has introduced additional duties which affect public authorities, private clubs and those selling, letting, controlling and managing property. The new duties are being implemented in stages: From December 2005: it has been unlawful for private clubs, with more than 25 members, t o discriminate against disabled people by providing less favourable treatment From December 2006: public bodies have a duty t o promote disability equality controllers of premises t o be extended t o cover reasonable adjustments private clubs have a duty t o make reasonable adjustments A new Code of Practice Rights of Access: Services and Premises (Services to the public, Public Authority Functions, Clubs and Premises) 52

is due t o be published by the Disability Rights Commission (DRC) in August 2006. The Code is a revision of the previous Code of Practice for Part 3 and expands on the additional duties placed on public authorities, private clubs and those selling, letting, controlling and managing property-

DDA Part 4: Education The Special Educational Needs and Disability Act 2001 (SENDA) amended Part 4 of the DDA and expanded the duties relating t o disabled pupils and students. Education providers are now required t o make 'reasonable adjustments' for disabled students and pupils. The duties cover all areas of education, schools, colleges, universities, adult education and youth services, including: 0

0

0

0

not t o treat disabled students or pupils less favourably than non-disabled students or pupils without justification t o make reasonable adjustments t o policies, practices and procedures that may discriminate against disabled students or pupils t o provide education by a 'reasonable alternative means' where a physical feature places a disabled studentlpupil a t a substantial disadvantage a duty on local education authorities in England and Wales t o plan strategically and increase the overall accessibility t o school premisesand the curriculum (a similar duty is placed on authorities in Scotland under the Education (Disability Strategies and Pupils' Education Records) (Scotland) Act 2002)

Additional duties placed on providers of post-16 education include the duty: not t o discriminate against existing and prospective disabled students by treating them less favourably in the provision of student services t o make reasonable adjustments t o provide auxiliary aids t o make adjustments t o physical features Many schools or furtherhigher education providers are also service providers (for

Appendices

example, where premises are used for evening classes, exhibitions or parents' evenings) and therefore also have duties under Part 3.

Disability Equality Duty The Disability Equality Duty (DED) comes into force in December 2006. The DED will have a significant impact on many organisations; it is estimated that there are 40,000 public bodies in Britain. All public authorities will have a general duty t o promote equality for disabled people. Specified bodies will also have to prepare a Disability Equality Scheme (DES) that demonstrates how they are meeting the general duty. The requirements of the general duty is that every public body shall in carrying out its functions have due regard t o the need to: e

e

promote equality of opportunity between disabled persons and other persons eliminate discrimination that is unlawful under the Act eliminate harassment of disabled persons that is related t o their disabilities promote positive attitudes towards disabled persons encourage participation by disabled persons in public life; and take steps t o take account of disabled persons' disabilities, even where that involves treating disabled persons more favourably than other persons

The Duty to Promote Disability Equality Statutory Code of Practice England and Wales and The Duty to Promote Disability Equality Statutory Code of Practice Scotland published by the DRC in December 2005, outlines what may need t o be considered in meeting both the General and Specific Duties.

The Codes of Practice for the DED identify important considerations for successful compliance with the new duty; these include staff expertise and training, partnerships and procurement and the need t o focus on effective organisational change.

Sources of useful information Organisations British Glass 9 Churchill Way Chapeltown Sheffield 535 2PY Tel: 0114 290 1850 Fax: 0114 290 1851 Email: infoQbritglass.co.uk Website: www.britglass.co.uk

Technical consultancy, troubleshooting, project management. British Standards Institution (BSI) 389 Chiswick High Road London W4 4AL Tel: 020 8996 9000 Fax: 020 8996 7001 EmaiI: cse rvicesQbsi-globaI.com Website: www.bsi.0rg.uk

Publishes British Standards including BS 8300:2001 (Incorporating Amendment No. 1) Design of buildings and their approaches to meet the needs of disabled people - Code of practice. Building Research Establishment (BRE) Bucknalls Lane Garston Watford WD25 9XX Tel: 01923 664000 Fax: 01923 664010 Email: enquiriesObre.co.uk Website: www.bre.co.uk BRE undertakes research and provides guidance on all aspects of construction.

Centre for Accessible Environments (CAE) 70 South Lambeth Road London SW8 1RL Telltextphone: 020 7840 0125 SMS: 07921 700098 Fax: 020 7840 5811 Email: infoOcae.0rg.uk Website: www.cae.0rg.uk

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Provides technical information, training and consultancy on making buildings accessible t o all users, including disabled and older people and carers of young children.

Centre for Window and Cladding Technology

(cwcr) University of Bath Claverton Down Bath BA2 7AY Tel: 01225 386541 Fax: 01225 386556 Email: cwctObath.ac.uk Website: www.cwct.co.uk CWCT is a leading information provider and trainer in the field of building envelopes and glazing. It is an industry funded Centre based at the University of Bath. It sets industry standards and publishes both standards and guidance.

Construction Products Association 26 Store Street London WClE 7BT Tel: 020 7323 3770 Fax: 020 7323 0307 Email: enquiriesOconstprod.org.uk Website: www.constprod.0rg.uk

Trade association representing manufacturers and suppliers of construction products, components and fittings.

Department for Communities and Local Government (DCLG) Eland House Bressenden Place London SW1E 5DU Tel: 020 7944 4400 Fax: 020 7944 9645 EmaiI: bregsb.brOcommunitiesgsi.gov.uk Website: www.communities.gov.uk'

For information on the Building Regulations.

Disability Rights Commission (DRC) DRC Helpline Freepost MID 02164 Stratford-upon-Avon CV37 9BR Tel: 08457 622 633 Textphone: 08457 622 644 Fax: 08457 778 878 EmaiI: enquiryOdrc-gb.org Website: www.drc.0rg.uk

Publishes codes of practice and other guidance related t o the DDA.

The Equality Commission for Northern Ireland Equality House 7-9 Shaftesbury Square Belfast BT2 7DP Tel: 028 90 500600 Fax: 028 90 248687 Textphone: 028 90 500589 Email: informationOequalityni.org

Works towards the elimination of discrimination and keeps the relevant legislation under review.

Department of Finance and Personnel (DFP) Building Regulations Unit Properties Division 10th Floor, River House 48 High Street Belfast BT1 2AW Tel: 028 9025 7326 Fax: 028 9051 8359 Email: info.bruOdfpni.gov.uk Website: www.df pni.gov. uk

Glass and Glazing Federation 44-48 Borough High Street London SE1 1XB Tel: 020 7403 7177 Fax: 020 7357 7458 Email: infoOggf.co.uk Website: www.ggf.co.uk

For information on the Northern Ireland Technical Booklets.

Trade Association for glass suppliers, manufacturers and fitters.

Appendices

Health and Safety Executive (HSE) Information Services Caerphilly Park Caerphilly CF83 3GG Tel: 0845 345 0055 Fax: 0845 408 9566 Email: hse.infolineOnatbrit.com Website: www.hse.g0V.uk Government agency responsible for regulating, providing guidance and monitoring health and safety. See website for regional offices.

Museums, Librariesand Archives Council (MLA) Victoria House Southampton Row London WCl B 4EA Tel: 020 7273 1444 Fax: 020 7273 1404 Email: infoOmla.gov.uk Website: www.mla.gov. uk National development agency working for and on behalf of museums, libraries and archives and advising government on policy and priorities for the sector.

National Association of Rooflight Manufacturers (NARM) NARM Secretariat 43 Clare Croft Middleton Milton Keynes MKlO 9HD Tel: 01908 692325 Fax: 01908 674122 Email:adminQnarm.org.uk Website: www.narrn.0rg.uk Trade association for rooflight manufacturers.

National Register of Access Consultants(NRAC) 70 South Lambeth Road London SW8 1RL Tel: 020 7735 7845 Fax: 020 7840 5811 SMS: 07921 700 089 Email: infobnrac.0rg.uk Website: www.nrac.0rg.uk

Enables clients quickly and easily t o locate suitable auditors and consultants, and provides a quality standard for those advising on the accessibility of the built environment for disabled people.

Royal Institute of British Architects (RIBA) 66 Portland Place London W1B 1AD Public information line: 0906 302 0400 Tel: 020 7580 5533 Fax: 020 7255 1541 EmaiI: infoQPinst.r iba.org Website: www.a rchitedure.com The RIBA advances architecture by demonstrating benefit t o society and excellence in the profession.

Scottish Building Standards Agency (SBSA) Denholm House Almondvale Business Park Livingston West Lothian EH54 6GA Tel: 01506 600 400 Fax: 01506 600 401 EmaiI: infobsbsa.gov.u k Website: wwws bsa.gov.u k For information on the Scottish Technical Handbooks.

The Stationery Off ice Ltd PO Box 29 Duke Street Norwich NR3 1GN Tel: 0870 600 5522 Fax: 0870 600 5533 EmaiI: customer.servicesOtso.co.uk Online ordering: www.ts0.co.u Wbookshop Sells printed versions of any item of legislation or any other official publication previously published by HMSO.

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Publicat ions Selected British and European Standards for glazing British/European Standard

Title

Types of glass BS EN 572-112004

Glass in building. Basic soda lime silicate glass products. Definitions and general physical and mechanical properties

BS EN 572-2:2004

Glass in building. Basic soda lime silicate glass products. Float glass

BS EN 1096-1:1999

Glass in building. Coated glass. Definitions and classification

Safety requirements for glazing BS 6262-1:2005

Glazing for buildings: General methodology for the selection of glazing

BS 6262-2:2005

Glazing for buildings: Code of practice for energy, light and sound

BS 6262-312005

Glazing for buildings: Code of practice for fire, security and wind loading

BS 626242005

Glazing for buildings: Safety related to human impact

BS 6262-612005

Glazing for buildings: Code of practice for special applications

BS 6262-7:2005

Glazing for buildings: Code of practice for the provision of information

BS EN 12600:2002

Glass in building. Pendulum test. Impact test method and classification of flat glass

BS 6206:1981

Specification for impact performance requirements for flat safety glass and safety plastics used in buildings

BS 6180:1999

Barriers in and about buildings. Code of practice

BS EN 14428:2004

Shower enclosures. Functional requirements and test methods

Security requirements for glazing BS EN 1063:2000

Glass in building. Security glazing. Testing and classification of resistance against bullet attack

BS EN 1522:1999

Windows, doors, shutters and blinds. Bullet resistance. Requirements and classification

BS EN 1523:1999

Windows, doors, shutters and blinds. Bullet resistance. Test method

BS 5357:1995

Code of practice for installation of security glazing

BS EN 356:2000

Glass in buildings. Security glazing. Testing and certification of resistance against manual attack

BS EN 13541:2001

Glass in building. Security glazing. Testing and classification of resistance against explosion pressure

Fire requirements BS 5588-7~1997

Fire precautions in the design, construction and use of buildings. Code of practice for the incorporation of atria in buildings

BS EN 357:2004

Glass in building. Fire resistant glazed elements with transparent or translucent glass products. Classification of fire resistance

Appendices

Other PAS 23-1:1999

General performance requirements for door assemblies. Single leaf, external door assemblies t o dwellings

BS 8000-7~1990

Workmanship on building sites. Code of practice for glazing

BS EN 673:1998

Glass in building. Determination of thermal transmittance (U value). Calculation method

BS 8213-1:2004

Windows, doors and rooflights. Design for safety in use and during cleaning of windows, including door-height windows and roof windows. Code of practice

Legislation, standards and codes of practice BS EN 81-70:2003 Safety rules for the construction and installation of lifts. Particular applications for passenger and goods passenger lifts. Accessibility t o lifts for persons including persons with disability British Standards Institution, 2003

BS 8300:2001 (Incorporating Amendment No. 1) Des.ign of buildings and their approaches t o meet the needs of disabled people - Code of practice British Standards Institution, 2001 BS 5395-1:2000 Stairs, ladders and walkways. Code of practice for the design, construction and maintenance of straight stairs and winders British Standards Institution, 2000 BS 8233:1999 Sound insulation and noise reduction for buildings. Code of practice British Standards Institution, 1999

BS 6180:1999 Barriers in and about buildings. Code of practice British Standards Institution, 1999

The Building Regulations 2000 Approved Document K: Protectionfrom falling, collision and impact The Stationery Office, 2000 Approved Document N: Glazing - safety in relation t o impact, opening and cleaning The Stationery Office, 2000 Approved Document M: Access t o and use of buildings The Stationery Office, 2004

The Building Regulations (Northern Ireland) 2000 TechnicaI Booklets: H: Stairs, ramps, guarding and protection from impact R: Access and facilities for disabled people V Glazing Great Britain Department of Finance and Personnel (Northern Ireland) The Stationery Office, 200 7 Non-domestic Technical Handbook Scottish Executive The Stationery Office, 2005 Code of Practice Rights of Access t o Goods, Facilities, Services and Premises Disability Rights Commission The Stationery Office, 2002 Code of Practice for providers of Post-16 education and related services Disability Rights Commission The Stationery Office, 2002 Code of Practice for Schools Disability Rights Commission The Stationery Office, 2002 Code of Practice - Employment and Occupation Disability Rights Commission The Stationery Office, 2004 Code of Practice - Trade Organisations and Qualification Bodies Disability Rights Commission The Stationery Office, 2004 The Duty t o Promote Disability Equality Statutory Code of Practice Disability Rights Commission The Stationery Office, 2005

E

Glass in Buildings

Other publications Glass in Building: A Guide to Modern Architectural Glass Performance D Button and B Pye (Eds) Pilkington Glass with Butterworth Architecture, 1993 A Specifiers' Guide for Display Cases by May Cassar and Peter Osborne Museums, Libraries and Archives Council, 1996 Code for interior lighting Chartered Institution of Building Services Engineers, 1997 Safety and security glass: a comprehensive guide to glass types, supply regulations and standards by David Crook and Ray lennings Glass Age and Window Construction for Miller Freeman, 2000 Glazing manual Glass and Glazing Federation

Glass: Structure and Technology in Architecture Stefan Behling and Sophia Behling (Eds) Prestel Publishing, 2000 Translucent Materials: Glass, Plastics, Metals Frank Kaltenbach (Ed) Weisel-Kommunikation, 2004 Guidance on glazing a t height by A Keiller et a1 Construction Industry Research and Information Association, 2005 Guide to Glass Standards for Application in Museums and Galleries Museum and Libraries Association Glass in workplaces: safety issues by S N Taylor Health and Safety Executive, 1999 The use of glass in buildings American Society for Testing and Materials, 2002

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RIBA Publishing RlBA Publishing is a leading provider of information in the fields of architecture and construction for specifiers and manufacturers, as well as for engineers, surveyors, construction lawyers, contractors, academics and students. We are committed t o delivering a wide range of products and services each year, t o the highest quality, in practice management, construction law, design, specifying, construction contracts, forms of appointment and associated guidance and monographs. With a comprehensive range of publications, products and services, and a history spanning more than 30 years, RlBA Publishing is the perfect partner to provide solutions t o all your business, professional and academic needs.

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