BS-8290-1-1991.pdf

BRITISH STANDARD BS 8290-1:1991 Incorporating Amendment No. 1 Suspended ceilings Part 1: Code of practice for design Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 05:40:58 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 8290-1:1991 This British Standard, having been prepared under the direction of the Elements and Components (of Diverse Materials) for Buildings Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 31 January 1992 © BSI 02-1999 The following BSI references relate to the work on this standard: Committee reference ECB/11 Draft for comment 90/14881 DC ISBN 0 580 20210 0 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Elements and Components (of Diverse Materials) for Buildings Standards Policy Committee (ECB/-) to Technical Committee ECB/11, upon which the following bodies were represented: Association of Structural Fire Protection Contractors and Manufacturers Cold Rolled Sections Association Construction Fixings Association Department of Health Department of the Environment (Property Services Agency) Fibre Cement Manufacturers Association Ltd. Gypsum Products Development Association Local Authority Organizations Loss Prevention Council Royal Institute of British Architects Suspended Ceilings Association Amendments issued since publication Amd. No.DateComments 7843August 1993Indicated by a sideline in the margin Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 05:40:58 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 8290-1:1991 © BSI 02-1999i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2Definitions1 3General design checklist2 4Information to be provided for the installer3 5Provision for services4 6Access5 7Structural performance5 8Environmental conditions5 9Deflection5 10Fire protection6 11Acoustic control7 12Control of condensation7 Appendix A Regulations for electrical installations9 Appendix B General principles of fire protection9 Appendix C Principles of fire resistance9 Appendix D Sound absorption13 Appendix E Sound insulation13 Figure 1 Some relevant tests for the control and containment of fire10 Figure 2 Fire tests for suspended ceilings11 Figure 3 Functions and requirements of a suspended ceiling over a fire12 Figure 4 Absorber response curves14 Figure 5 Sound transmission14 Table 1 Maximum deflections between points of support5 Table 2 Control of condensation in roofs above suspended ceilings8 Publication(s) referred toInside back cover Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 05:40:58 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 8290-1:1991 ii © BSI 02-1999 Foreword This Part of BS 8290, prepared under the direction of the Elements and Components (of Diverse Materials) for Buildings Standards Policy Committee, deals with the design of suspended ceilings of dry construction with suspension systems of lightweight corrosion-resistant steel or aluminium alloy sections. BS 8290 supersedes CP 290:1973 which is withdrawn. BS 8290 is published in separate Parts, the other Parts being as follows: Part 2: Specification for performance of components and assemblies; Part 3: Code of practice for installation and maintenance. A suspended ceiling is a membrane suspended below a structural floor or roof to provide a finished soffit. Suspended ceilings have a variety of functions in forming the internal environment of buildings. They can provide concealment of services, protection of structure against fire, decorative finishes, thermal insulation and illumination. They can also provide heating and ventilation, and contribute to acoustic absorption, sound insulation and the reduction of condensation. Suspended ceilings are constructed from pre-fabricated components which together form an integrated system. For this reason they are usually installed by specialist ceiling contractors. BS 8290-1 is intended for the designer and gives recommendations for design as far as possible in terms of performance. Detailed recommendations for construction have been omitted so that innovation is not inhibited. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 14, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 05:40:58 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 8290-1:1991 © BSI 02-19991 1 Scope This Part of BS 8290 gives recommendations for the design of suspended ceilings of dry construction, with suspension systems of lightweight steel or aluminium alloy sections. NOTEThe titles of the publications referred to in this Part of BS 8290 are listed on the inside back cover. 2 Definitions For the purposes of this Part of BS 8290 the definitions given in BS 6100 apply, together with the following. Terms from BS 6100 that are particularly relevant are reproduced below. 2.1 suspended ceiling ceiling hung at a distance from the floor or roof above 2.2 open ceiling suspended ceiling formed of louvres, open cells or similar ceiling components 2.3 luminous ceiling ceiling of translucent material or open ceiling with lamps in the ceiling void to light the space below 2.4 ceiling suspension system assembly of ceiling components for a suspended ceiling 2.5 exposed system ceiling suspension system with inverted T (tee) sections in which the infill units, open cells or similar components usually rest on the visible table of the system 2.6 concealed system ceiling suspension system with sections onto which infill units are slotted or mechanically fixed 2.7 main runner ceiling component suspended from the ceiling hangers in an exposed system or mechanically fixed 2.8 primary channel ceiling component suspended from the ceiling hangers in a concealed system or open ceiling 2.9 ceiling hanger ceiling component that is used to connect a main runner or primary channel to the supporting structure above 2.10 tile section ceiling component that is fixed to the primary channel to support ceiling tiles 2.11 cross member ceiling component that spans between the main runners 2.12 noggin ceiling component that spans between tile sections 2.13 spline strip inserted into preformed grooves of adjacent ceiling infill units to form a concealed mechanical joint for the purpose of restricting air movement through the tile joints 2.14 perimeter trim section fixed at the perimeter of a ceiling to support the outer components of the ceiling surface 2.15 ceiling linear strip ceiling component that consists of a profiled section and provides part of a ceiling surface 2.16 metal tray metal ceiling component with formed edges that provides part of a ceiling surface 2.17 spring tee ceiling component that is fixed to the primary channels to support metal trays 2.18 open cell ceiling component that is formed as a grille and that provides part of a ceiling surface 2.19 tile infill unit with maximum dimensions of 600 mm × 600 mm 2.20 panel infill unit with dimensions in excess of 600 mm × 600 mm Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 05:40:58 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 8290-1:1991 2 © BSI 02-1999 2.21 plank infill unit with length in excess of 600 mm and a length at least three times the width 2.22 board dry lining unit mechanically fixed to a concealed grid 2.23 kerf preformed groove in the edge of a ceiling infill unit to accommodate the tile section in a concealed grid system 2.24 top fixing means or device by which ceiling hangers are secured to the building structure 2.25 fire protection design features, systems, equipment, buildings, or other structures to reduce danger to persons and property by detecting, extinguishing or containing fires 2.26 fire resistance measure of the ability of a construction or component to fulfil for a stated test time one or more of the following: the required stability, fire integrity, thermal insulation, other expected duty 3 General design checklist When designing or selecting a suspended ceiling system the points listed in items a) to g) should be considered. a) Functional aspects Functional aspects to be considered include the following: 1) concealment of structure; 2) concealment of services; 3) decorative appearance; 4) thermal insulation; 5) sound absorption; 6) sound insulation; 7) fire protection; 8) control of condensation; 9) hygiene control; 10) ventilation; 11) heating; 12) air conditioning; 13) illumination; 14) electrical earthing and bonding. b) Location constraints Location constraints to be considered include the following: 1) dimensional discipline of the building; 2) position of ceiling with reference to the building structure; 3) method of attachment to supporting structure; 4) provision of fixing points; 5) constraints of adjoining components and services. c) Structural aspects Structural aspects to be considered include the following: 1) items requiring support from the ceiling; 2) vertical and lateral loads from the partition; 3) the environmental conditions (see clause 8); 4) support of associated fittings; 5) wind loading (positive and negative). d) Access Access criteria to be considered include the following: 1) whether all panels, or only certain panels are demountable; 2) trap door access. e) Appearance and design Appearance and design criteria to be considered include the following: 1) compatibility of components of the ceiling assembly with one another; 2) suspension system, e.g. concealed, semi-concealed or exposed grid; 3) decorative finish, e.g. material, texture, colour; 4) type and shape of ceiling infill units; 5) continuous membrane, e.g. jointless system; 6) non-continuous membrane, e.g. linear strip or open cell. f) Durability and maintenance Durability and maintenance criteria to be considered include the following: 1) the expected life of the ceiling; 2) replacement of the ceiling during the life of the building; 3) repair and redecoration of the ceiling; 4) any special cleaning requirements; Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 05:40:58 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 8290-1:1991 © BSI 02-19993 5) maintaining precautions against fire hazards. g) Special considerations Special consideration should be given to the following: 1) dust free environment; 2) ability of the ceiling to withstand impact; 3) severe environment (e.g. humidity); 4) corrosive atmospheres. 4 Information to be provided for the installer 4.1 Basic design criteria Basic design criteria should be given for the following. a) Height of the suspended ceiling above the finished floor level. b) Either the level of the structural soffit above the ceiling, or depth of suspension. c) Details of the structure from which the ceiling is to be suspended and any limitations affecting the top fixing of the ceiling hangers. d) Details and size of any items projecting into the ceiling void, e.g. downstand beams. e) Details of any other items contained within the ceiling void, e.g. ventilation ducts. f) Details of any removable panels for access to services, controls etc., together with details of those areas in which complete demountability is required for unobstructed access to services. g) Details of any rooflights, blind boxes, and soffits to window heads. h) Siting of sprinklers, fire detectors, access to fire dampers, air distribution outlets or other terminal equipment. i) Position and detail of partition head members and facility to be provided by the ceiling, e.g. resistance to upward pressure from jacked-up partitions. j) Position and nature of cavity barriers. k) Position and type of any luminaires. l) Details of edge treatments and abutments. m) Details of integral and applied finishes. 4.2 Drawings Layout drawings should be provided at a minimum scale of 1 : 100, and should be cross-referred to drawings illustrating perimeter details, changes in level and junctions between dissimilar materials. Where the layout of ceiling infill units is important, reflected ceiling plans should be included showing setting out points for the ceiling. Where recessed luminaires or trunking are to be used these should be indicated on the reflected ceiling plans together with an indication as to whether the ceiling installer is required to provide support for them. The approximate weight of recessed luminaires or trunking and, where known, the manufacturers reference should also be given. The information recommended in 4.1 should be included in the drawings. Alignment with modular elements such as structural columns or window mullions should be considered. NOTEManufacturing tolerances in ceiling components are smaller than those usually accepted in building structures. 4.3 Interaction of ceiling system and building services Areas of potential interaction between the ceiling system and building services should be identified. The following criteria should be considered. a) Coordinated layout of services with the ceiling module. b) Dimensional coordination of recessed luminaires and other terminal equipment with the infill unit module. c) Additional support for luminaires, air distribution outlets etc. d) Whether flanges are adequate and correctly dimensioned when ceiling infill units are to be partially supported by luminaires or air terminal devices. e) Lateral stability of ceiling grid when interrupted by electrical trunking, luminaires or other ceiling level equipment. f) Obstruction of ceiling hangers by heating and ventilating ductwork. g) Insufficient vertical space where ductwork recessed luminaires and/or ceiling suspension components overlap. h) Insufficient headroom for upward opening access panels. i) Sprinkler heads coinciding with main support sections of the ceiling system. j) Location of access panels for services. k) Shallow angle light across the ceiling from luminaires, or high level windows, which may give rise to excessive shadow at joints of infill units. l) Electrical equipment installed in or above the ceiling, which may require to be electrically earthed and bonded to the grid. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 05:40:58 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 8290-1:1991 4 © BSI 02-1999 4.4 Time schedule and site conditions For installation programme, provision of site facilities and site conditions for i