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BRITISH STANDARD Mechanical vibration and shock Ð Vibration isolation of machines Ð Information for the application of source isolation ICS 17.160 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BS EN 1299:1997 +A1:2008 BS EN 1299:1997+A1:2008 National Foreword This British Standard is the UK implementation of EN 1299:1997+A1:2008 It supersedes BS EN 1299:1997 which is withdrawn The start and finish of text introduced or altered by amendment is indicated in the text by tags Tags indicating changes to CEN text carry the number of the CEN amendment For example, text altered by CEN amendment A1 is indicated by !" The UK participation in its preparation was entrusted by Technical Committee GME/21, Mechanical vibration, shock and condition monitoring, to Subcommitee G ME/21/6, Human exposure to mechanical vibration and shock A list of organizations represented on this subcommittee can be obtained on request to its secretary This publication does not purport to include all the \necessary provisions of a contract Users are responsible for its correct application Compliance with a British Standard cannot confer immunity from legal obligations This British Standard was published under the authority of the Standards Policy and Strategy Committee on 15 October 1997 © BSI 2009 ISBN 978 580 61498 A mendments/corrigenda issued since publication Date Comments 30 April 2009 Implementation of CEN amendment A1:2008 EUROPEAN STANDARD EN 1299:1997+A1 NORME EUROPÉENNE EUROPÄISCHE NORM November 2008 ICS 17.160 Supersedes EN 1299:1997 English Version Mechanical vibration and shock - Vibration isolation of machines - Information for the application of source isolation Vibrations et chocs mécaniques - Isolation vibratoire des machines - Informations pour la mise en oeuvre de l'isolation des sources Mechanische Schwingungen und Stưße Schwingungsisolierung von Maschinen - Angaben für den Einsatz von Quellenisolierungen This European Standard was approved by CEN on 30 December 1996 and includes Amendment approved by CEN on October 2008 CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member This European Standard exists in three official versions (English, French, German) A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG Management Centre: rue de Stassart, 36 © 2008 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members B-1050 Brussels Ref No EN 1299:1997+A1:2008: E BS EN 1299:1997+A1:2008 EN 1299:1997+A1:2008 (E) Contents Page Foreword Introduction Scope Normative references Definitions Purpose of source isolation 5 Applicability of vibration isolation .5 6.1 6.2 6.2.1 6.2.1.1 6.2.1.2 6.2.1.3 6.2.1.4 6.2.1.5 6.2.2 6.2.2.1 6.2.2.2 6.2.2.3 6.2.2.4 6.2.2.5 6.3 6.3.1 6.3.2 6.3.3 Information for the choice of an isolation system for a machine General Information to be supplied by the machine manufacturer Physical data of the machine .6 Machine drawing Vibration excitation Special requirements .7 Electrical features Special requirements for mechanical stability Physical data of the isolation system General data Dynamic behaviour Durability .8 Environmental data Maintenance data Information that the machine manufacturer shall require from the user .9 Technical information on the surrounding structure of the machine Vibration and shock situation of the surrounding structure Climatic environment Guidelines for the validation of isolation efficiency Annex A (informative) Elements for vibration isolation 11 A.1 Springs 11 A.1.1 Elastomer springs 11 A.1.2 Metal springs 12 A.1.3 Air springs 14 A.2 Dampers 15 A.3 Combinations of springs and dampers .16 A.4 Active vibration isolators 17 Annex B (informative) Bibliography 18 Annex ZA (informative) !Relationship between this European Standard and the Essential Requirements of EU Directive 98/37/EC" .19 Annex ZB (informative) !Relationship between this European Standard and the Essential Requirements of EU Directive 2006/42/EC" 20 BS EN 1299:1997+A1:2008 EN 1299:1997+A1:2008 (E) Foreword This document (EN 1299:1997+A1:2008) has been prepared by Technical Committee CEN/TC 231 “Mechanical vibration and shock”, the secretariat of which is held by DIN This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by May 2009, and conflicting national standards shall be withdrawn at the latest by December 2009 This document includes Amendment 1, approved by CEN on 2008-10-05 This document supersedes EN 1299:1997 The start and finish of text introduced or altered by amendment is indicated in the text by tags ! " This European Standard has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s) !For relationship with EU Directive(s), see informative Annexes ZA and ZB, which are integral parts of this document." According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom BS EN 1299:1997+A1:2008 EN 1299:1997+A1:2008 (E) Introduction Vibration isolation is a measure used to either reduce significantly any transmission of periodic, shock or random type forces from a machine into surrounding structures (source isolation, protection from emission) or to protect sensitive machines, instruments, buildings and people from vibration received by their surroundings (receiver isolation, protection from immission) In both cases, the use of vibration isolators creates a massspring system whose vibration response is critically influenced by the characteristics of the source of vibration, the dynamic characteristics of the machine, the structure to which the machine is mounted and the characteristics of the elastic and damping elements Optimization of the system to satisfy protection criteria requires a full and detailed knowledge of all the factors which influence the design and effective application of vibration isolation to a particular machine or installation The interchange of information between the machinery manufacturer, the isolation supplier and the user plays a key role in achieving this Scope This European Standard gives guidelines to ensure that manufacturers of machines provide adequate information on application of vibration isolation to reduce the risks arising from vibration generated by their machines Guidelines are also provided to ensure that users furnish sufficient information regarding their applications to suppliers of machines or, where applicable, to the supplier of the isolation system, to enable the optimum selection and design of vibration isolation This European Standard is restricted to source isolation Although this standard is primarily intended for the use of new machines, it may be applied to the installation of used machines, too This European Standard is addressed to manufacturers and installers of a machine, as a guide to define relevant parameters for the choice and installation of a vibration isolation system to be used with the machine NOTE This European Standard may also be applied by users of machines already installed, who use or wish to use vibration isolation to solve a vibration problem caused by the machine This European Standard shall not be considered as a manual for the design or installation of an isolation system Examples of elements of vibration isolation are shown in Annex A only for information Normative references !The following referenced documents are indispensable for the application of this document For dated references, only the edition cited applies For undated references, the latest edition of the referenced document (including any amendments) applies." ISO 2041:1990, Vibration and shock ISO 7626-1:1986, Vibration and shock – Experimental determination of mechanical mobility – Part 1: Basic definitions and transducers BS EN 1299:1997+A1:2008 EN 1299:1997+A1:2008 (E) Definitions For the general terms and their definitions used in this European Standard, see ISO 2041 and ISO 7626-1 Purpose of source isolation The purpose of source isolation is to protect the surrounding structure from vibration by taking action on the installation of the source itself A source isolation system may be necessary a) For the safety of the operators of the vibrating machines; b) For the safety of bystanders to vibrating machines; c) For the safety of structures or buildings containing vibrating equipment; d) For the safety of people in buildings that may be subjected to intense vibration excitation; e) When there are limiting values for vibration in legislation which are exceeded Applicability of vibration isolation A source isolation shall be used additionally to design measures for reducing vibration; it shall not be a substitute to such measures It can be applied a) when vibrating machines are designed or installed; b) when buildings containing vibrating machines are designed or modified Prior analysis of vibration phenomena and analysis of background vibration is necessary Time history monitoring and frequency analysis for a sufficient period of time relative to the working cycle of the machine is important Analysis of frequency response functions for the structures that transmit and receive vibration will facilitate the "best matching" of the structures and avoid coincidence between dominant frequencies of the source and the natural frequencies of these structures A determination of the background vibration shall be carried out in order to know the inherent vibration level below which normally no isolation is necessary NOTE In case of correction of an existing situation, the vibration (displacement, velocity or acceleration) should be measured simultaneously on and close to the mounting points of the machine, at operator's or bystander's position Measurements shall be made in the environmental conditions relevant for the location of the machine The measurements and analysis shall help in providing an understanding of the origin of the problem and possibly give an indication of possible solutions Measurements should be made in accordance with an appropriate standard, and the standard should be identified The mounting points of transducers and directions of measurement shall be reported BS EN 1299:1997+A1:2008 EN 1299:1997+A1:2008 (E) In a complex situation where isolation systems are used, expert advice should be sought The situation is especially complex when the machine and/or the supporting structure has natural frequencies (vibrational modes) in the frequency range of interest Information for the choice of an isolation system for a machine 6.1 General In order to select appropriate isolators and correctly install source isolation, an exchange of information is needed between the machine manufacturer, the supplier of the isolator and the machine user The following paragraphs list the information required for an optimized machine isolation If the machine manufacturer is also the supplier of the isolation system, some of the information in the following paragraphs may seem to be not relevant Nevertheless, some of this information may be useful when replacement parts have to be provided and should be part of the instruction handbook The choice of the isolation system shall take into consideration not only the static characteristics of the machine, but also its dynamic characteristics (mobility) and the dynamic characteristics of its surrounding structure (and further sources) It will often be necessary for the supplier of a vibration isolation system to ask for more detailed information from the user in order to provide the best possible solution 6.2 Information to be supplied by the machine manufacturer The manufacturer shall supply to the user of the machine as much of the following information as is needed to ensure proper installation of the machine If necessary, he should use the support of the supplier of the vibration isolation system 6.2.1 6.2.1.1 Physical data of the machine Machine drawing A drawing shall be furnished giving: a) The outline and installation of the machine, if appropriate, including an intermediate foundation prescribed by the machine manufacturer; b) The overall dimensions; c) The total weight and the location of the centre of gravity Rotational inertia shall also be included d) Specifications of bolt sizes and special connectors for securing the machine Locations of attachments, tapped holes, tolerances and any special material considerations shall be indicated on the drawing e) Identification and direction of the three mutually perpendicular axes with origin in the centre of gravity of the unit to be isolated under conditions of preferred orientation; f) The normal machine orientation with respect to the vertical The direction of major shock or vibration shall be indicated Feasible structural attachment points shall be given These points frequently determine the isolation system in relation to orientation, centre of gravity, etc 6.2.1.2 Vibration excitation The vibration excitation by a machine as characterised by its exciting forces and couples as a function of frequency or in form of time history shall be described in the detail necessary to ensure the safe installation and use of machinery BS EN 1299:1997+A1:2008 EN 1299:1997+A1:2008 (E) Examples are: Inherent rotational frequency forces and couples; Residual rotational frequency forces and couples after balancing; Forces and couples caused by reciprocating masses; Torque reaction couples; Amplitudes and/or frequencies of gas pulsation phenomena; Frequencies of aerodynamic phenomena (e.g for fans); Electromagnetic forces and frequencies associated with electrical rotating machines or transformers 6.2.1.3 Special requirements Special features peculiar to the equipment shall be covered in the machine description and by drawings Among such special features are a) Electrical connectors, tubing, ducting or piping which might modify the mechanical response of the mounting system (type, size, stiffness, etc); b) Externally applied forces and moments; c) Required access areas; d) Minimum clearance required for cooling air flow Any temperature gradients which might adversely affect isolator operation shall be shown on the drawing and the expected temperature range shall be given e) Maximum clearance between equipment and foundation, where applicable 6.2.1.4 Electrical features Provisions for grounding and applicable specifications shall be indicated on the drawing, by an attached note 6.2.1.5 Special requirements for mechanical stability Special requirements for mechanical stability shall be given For example, special care is needed where equipment with a high or variable centre of gravity is supported by isolators located below the centre of gravity, or where uncompensated side thrusts exist 6.2.2 6.2.2.1 Physical data of the isolation system General data The supplier of the isolation system shall supply detailed information on characteristics of the isolation system: a) Type of isolation system; b) Materials of the isolation system; c) Weight of the isolation system; d) Levelling features; BS EN 1299:1997+A1:2008 EN 1299:1997+A1:2008 (E) e) Static stiffness of isolators; f) The maximum and minimum weight forces (expressed in Newtons) under operating conditions of the machine; g) Dimensions and location of the isolation (e.g drawing); h) Creep of isolators relative to load and time 6.2.2.2 Dynamic behaviour The supplier shall describe the translational and rotational dynamic behaviour of the isolation system in terms of dynamic stiffness The environmental conditions and the rate of loading under which the load-deflection data were obtained shall be described and tolerances shall be given However, where necessary, as an alternative, the supplier can describe dynamic behaviour by transmissibility characteristics measured in a testing setup which is fully described Dynamic behaviour may be related to variations in the following input parameters: a) Resonance frequency as a function of load; b) Amplitude; c) Temperature; d) Damping The supplier shall describe the efficiency of isolation in the three principal directions, indicating applicable frequencies 6.2.2.3 Durability The supplier shall present such information on durability or rather on the change of the physical characteristics as: a) Endurance limit associated with repeated deflections and shocks; b) Creep (permanent deformation) data, where applicable, and how the data have been obtained; c) Ageing effects due to storage in specified environments including maximum and minimum temperatures 6.2.2.4 Environmental data The supplier shall supply the following information on the isolators as necessary to ensure proper use: a) The upper and lower temperature limits beyond or below which the isolator under rated loads will not properly perform its function or will undergo permanent changes in characteristics; b) The ability of the isolator to withstand corrosion or deterioration caused by such factors as humidity, water, salt spray, fungus, ozone, oils and fuels, corrosive vapours, sunshine, etc.; c) The ability to perform under adverse conditions, for example, in an atmosphere loaded with sand or dust; d) Permissible storage environment 6.2.2.5 Maintenance data The supplier shall supply details of any maintenance, periodical inspection and service requirements BS EN 1299:1997+A1:2008 EN 1299:1997+A1:2008 (E) 6.3 Information that the machine manufacturer shall require from the user 6.3.1 Technical information on the surrounding structure of the machine A brief description required for a sufficient understanding of the technical details of the proposed arrangement shall be provided This information shall include: a) The type of structure in which the machine is to be mounted (ship, steel building, concrete building, power plant, etc.); b) The location in the structure (engine room, main deck, roof, etc.); c) Data on the supporting structure (conditions of ground, e.g permissible load of the ground, ground water level versus floor, natural frequencies and mobility of the supporting structure); d) The isolation efficiency or user's criteria for acceptance (neighbourhood, e.g residential area, industrial area; type of neighbouring machines, e.g testing machines, punching machines) 6.3.2 Vibration and shock situation of the surrounding structure The vibration and shock situation of the surrounding structure before the installation of the machine shall be described with respect to the three axes by the amplitude (displacement, velocity or acceleration), corresponding frequencies and duration over which this will occur Time history, spectral analysis, and other descriptive parameters are necessary 6.3.3 Climatic environment The user shall supply, as applicable, the following information on the climatic environment: a) The upper and lower temperature limits; b) Humidity, presence of water, sand or dust, salt spray, ozone, oils, solvents, radiation, etc Guidelines for the validation of isolation efficiency Normally, the supplier of isolated machines or the supplier of isolating systems has to prove the efficiency of vibration isolation in the surrounding structure of the machine This efficiency has to be evaluated by an experimental and contractual method Where machines are made in mass production such evaluation may be performed under normalised installation conditions The manufacturer shall in such cases provide information on the installation conditions which have been used for the evaluation If relevant, a) The measurement and the evaluation of vibration have to be made before installation as in 6.3.2 It shall be performed in contractual positions and under expected environmental conditions for the future machine; b) The measurement positions and the measurement results shall be reported; c) The acceptable values shall be communicated to the machine supplier (or machine/isolator supplier); d) The limit values accepted by the supplier shall be contractual; e) After installation, measurements shall be made at the contractual positions and conditions, using the measurement method specified and the specified processing and analysis of the results; BS EN 1299:1997+A1:2008 EN 1299:1997+A1:2008 (E) f) The values measured shall be compared with the contractual limit values NOTE In case of correction of an existing situation, the measurements are made in the same conditions as in Clause in defined positions The positions should be the positions of the disturbed subjects (operator's or worker's positions, office floors, neighbouring buildings, etc.) As in Clause 7, acceptable limit values should be defined contractually between the user and the supplier After correction, measurements should be carried out as described in Clause The results should be compared with the contractual values In more complex situations more detailed measurements will be required 10 BS EN 1299:1997+A1:2008 EN 1299:1997+A1:2008 (E) Annex A (informative) Elements for vibration isolation A.1 Springs Springs are used to provide elastic, vibration and shock isolating supports for machines, i.e they are construction elements which deform, predominantly, elastically Ideal springs in the theoretical sense cannot be realised in practice since each spring shows a certain amount of mass and damping While for calculation of vibration in the frequency range of interest in this European Standard the mass of the spring can be neglected, the damping is strongly dependent on the spring material A.1.1 Elastomer springs Because of its elastic deformability and its small Young's modulus, elastomers are appropriate spring materials Compared to metal springs, elastomer springs have larger material damping Deformation characteristics, such as stiffness and damping, depend on the choice of basic material and the components of the material mixture, as well as the shape of the spring They are also affected by environmental conditions, e.g temperature The long-term creeping depends strongly on the composition of the material The material has visco-elastic properties Usually, static and dynamic stiffness of elastomer springs are different, the dynamic stiffness is greater than the static The natural frequencies of the isolated system should be calculated only from the dynamic stiffness With elastomer springs vertical natural frequencies of Hz to 20 Hz can be achieved In general, the load-deflection curve is non-linear but in practice for operational loading it can be linearized The following factors are important for the load capacity and the durability of elastomer springs: a) Material and material mixture; b) Design of the spring; c) Static load, dynamic load; d) Vibration amplitude and frequency of the vibrating system By their flexible design, the connection with metal parts, and by the wide range of possible material combinations, these springs can be adapted to a wide range of applications Elastomer springs can be used as single elements or as distributed plates or mats The detailed design of elastomer springs is determined by the type of loading (compression forces, shear forces, torsion moments, bending moments, or combinations thereof) Figure A.1 shows some examples of elastomer springs For large, distributed compression loads, elastomer springs in the form of plates or mats are common The vertical natural frequencies are usually higher than 12 Hz for those installations 11 BS EN 1299:1997+A1:2008 EN 1299:1997+A1:2008 (E) Figure A.1 — Examples of elastomer springs A.1.2 Metal springs Metal springs are not sensitive to large temperature differences and they are resistant to most organic substances For the vibration isolation of machines, metal springs are used which are made preferably from spring steel in the form of wire strings, plates and rods, specially made for this purpose There is no difference between static and dynamic stiffness of metal springs Depending on the type and design of spring, the load-deflection curve can be linear, progressive or degressive With metal springs vertical natural frequencies of 1,5 Hz to Hz can be achieved Metal springs have the ability to store high deformation energies at large deflection amplitudes Their spring characteristics not change with age In Figure A.2 examples of different types of metal springs and their load-deflection curves are shown 12 BS EN 1299:1997+A1:2008 EN 1299:1997+A1:2008 (E) Key a) helical spring b) spiral spring c) flexural spring d) conical spring e) disk spring column of single discs f) disk spring column of spring packets (laminated single discs) g) laminated leaf spring h) ring spring F load s deflection in the direction of load F h and t dimensions The areas in the load-deflection curves f) to h) indicate hysteresis due to friction damping Figure A.2 — Metal springs and their load-deflection curves (characteristic) 13 BS EN 1299:1997+A1:2008 EN 1299:1997+A1:2008 (E) The helical compression spring is the metal spring generally used for the vibration isolation of machines Because of its in a wide deflection range largely linear characteristics (load-deflection curve) and the wide choice of spring stiffnesses available, for all axes, this type of spring is particularly well suited for applications to the resilient mounting of machines of most types Figure A.3 shows an example of a typical spring unit The load capacity of such typical spring units normally ranges from a few Newtons up to approximately 1500 kN The transverse or horizontal spring constant of a helical compression spring can be varied over a wide range, relative to the vertical spring constant, by an appropriate choice of spring dimensions Figure A.3 — Typical spring unit made of helical compression springs A.1.3 Air springs In principle, an air spring consists of a closed gas filled volume with elastic sides (see Figure A.4) When the load changes the spring deflects, by deflection of the elastic sides, causing change of volume which results in a change of pressure This applies to pistons in cylinders as well as to the various bellows designs which are manufactured The deflection characteristic of air springs depends on the balance between the external load and the pressure difference between internal pressure and external pressure (for example atmosphere) multiplied by the effective area For level control, air springs are supplied in non-controllable and controllable designs 14 BS EN 1299:1997+A1:2008 EN 1299:1997+A1:2008 (E) Figure A.4 — Examples of air springs A.2 Dampers Dampers are used to limit the movement of elastically supported systems while passing through resonances in the case of periodical excitation or in cases of shock or random excitation They are mounted in parallel with the spring units and convert mechanical energy to heat They are divided into dampers which utilise damping between rigid bodies (friction dampers, see Figure A.5) and dampers which utilise energy exchange in liquid (liquid dampers, see Figure A.5) or gaseous media The force-velocity characteristics can be made independent of velocity, progressive, linear or degressive Attention shall be paid to the risk of structure-borne noise problems when using friction dampers The most important types of dampers for the vibration isolation of machines used in combination with spring units are liquid viscous dampers Viscous dampers are particularly suitable for large vibration amplitudes at low to medium high frequencies They consist of damper casing, damping medium and piston The piston immersed in the damping medium can move in all directions (vertical and horizontal) up to a limit set by the casing of the damper The damper is, therefore, able to reduce vibration in all six degrees of freedom 15 BS EN 1299:1997+A1:2008 EN 1299:1997+A1:2008 (E) Key friction lining adjustment screw compression spring piston casing liquid medium Figure A.5 — Design of a friction and a liquid viscous damper A.3 Combinations of springs and dampers Damping as an important part of the vibration isolation system – either in form of material damping or in form of integrated dampers (see Figure A.6) – is required a) In all cases where an increase of vibration amplitude on passing through resonance frequencies has to be avoided; b) For most rotating machines whose operating conditions could give rise to unbalance forces; c) For the absorption of short circuit torque transients produced by electrical machines; d) For the stabilisation of machines and systems which have to be resiliently mounted on foundations of inadequate mass for technical or economical reasons; e) To secure a rapid decay of shock induced vibration 16 BS EN 1299:1997+A1:2008 EN 1299:1997+A1:2008 (E) Key spring piston liquid damper volume drilling load volume interface plate membrane Figure A.6 — Combinations of springs and dampers A.4 Active vibration isolators This European Standard is dealing with passive vibration isolation systems only (consisting of springs and dampers) In special cases, it may be possible to reduce vibration by using dynamic vibration absorbers or active tuned mass dampers 17 BS EN 1299:1997+A1:2008 EN 1299:1997+A1:2008 (E) Annex B (informative) Bibliography [1] !EN 1032, Mechanical vibration — Testing of mobile machinery in order to determine the vibration emission value" [2] !ISO 2017-1:2005, Mechanical vibration and shock — Resilient mounting systems — Part 1: Technical information to be exchanged for the application of isolation systems" 18