Introduction to machine safety

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1 A practical approach to machinery safety Overview of relevant standards Glossary of abbreviations and terminology Introduction to machine safety

Introduction to machine safety A practical approach to machinery safety Basic principles of European legislation states that we must focus our efforts on Preserving and protecting the quality of the

2 Introduction to machine safety A practical approach to machinery safety Basic principles of European legislation states that we must focus our efforts on Preserving and protecting the quality of the environment and protecting human health through preventive actions. The EU Commission and the Council of the European Union have published various s: The Machinery Aimed at manufacturers of machinery and safety devices to be used on machinery. The Work Equipment Aimed at organisations that operate machinery. Additional directives e.g. Low Voltage EMC ATEX European standards on the safety of machinery To be able to implement the objectives and requirements defined in the European s in practice, a number of technical standards exist to describe and specify these requirements in detail. For further information or advice on European s and standards please contact our technical support team. They will be happy to supply information on standards, clarify any points and assist with your application telephone The directives are available to download: LC Automation has many years of experience in the machinery safety market. We offer one of the widest ranges of brand leading, top quality safety products available from one supplier in the UK. The diverse product range allows us to objectively evaluate safety applications and recommend the best fit solution. Support and safety services A nationwide team of sales engineers offers local support, plus back up by a technical support team and application engineers. We can guide The objective of safety technology is to keep the potential hazards for man and the environment as low as possible by applying the relevant technology. However this should be achieved without imposing unnecessary restrictions on industrial production, the use of machines and the production of chemical products Manufacturer EU agreement Art. 95 Art. 137 Low Voltage 2006/95/ EC Removal of trade barriers within the EU Machinery 2006/42/ EC Law product on equipment safety GPSG and Law EMC on Mandate from the EU Commission. Standards institute for the preparation of safety standards CEN/CENELEC On the application of harmonised standards, it can be assumed that the directives are met. Declaration of conformity CE marking Product Safety 2001/95/ EC EMC 2004/108/ EC Implementation of the EN standards without charge. Harmonised if published in the Official Journal of the EU Safe machine Order based on applicable regulations Choosing the right safety partner Safe machine in operation User Collaboration between EU states on social issues Safety and Health of Workers at Work 89/391/EEC 2001/45/EC to amend the directive 89/655 EEC Work Equipment 89/655/EEC 95/63/EC to amend the directive 89/655/EEC Law on health and safety Regulations on occupational safety In Germany: Berufsgenossenschaft (professional association) requirements n regulations n rules n information Machine operator (takes over the responsibility) clients though the various stages of a project ensuring they meet their safety obligations. Working in partnership with our suppliers we offer a full range of safety services from risk assessment, product specification, system design and build through to validation. Safety training Our training department offers a range of automation and safety training courses. For further information and course schedules please visit lcautomation.com 450 Call Blackburn or Chippenham

3 Introduction to machine safety The process to achieve and operate safe machinery Getting started l Understand the EU s and Standards l Identify which standards apply to your machine or project l Decide who will be affected and what actions have to be taken. A basic principle is to always try and design out any dangerous part of a machine. If you are a user of equipment you must consider the operator, maintenance staff and the public. Six steps to a safe machine The information opposite has been taken from the Sick publication Guidelines Safe Machinery (Six steps to a safe machine) this outlines a process to help companies meet their safety obligations. This and other documents on safety can be downloaded from the LC Automation web site /content/ OurSuppliers/SickUK.aspx Sources of information available from LC Automation Ltd Publications n Guidelines Safe Machinery (Six steps to a safe machine) Published by Sick n The New Safety Compendium Published by Pilz n A New Approach to Machine Safety: EN ISO :2006 Safety-related Parts of Control Systems Published by Schmersal Useful websites n LC Automation n Health & Safety Executive (HSE) n British Standards Institute (BSi) Legislation, directives, standards w European directives w Duties of the machine producer w Standards w The various types of standards w Notified bodies, insurance and authorities Six steps to a safe machine Risk assessment w The risk assessment process w Machine functions w Identifying hazards w Risk determination & risk evaluation w Documentation Safe design w Mechanical construction w Operating and maintenance concept w Electrical equipment w Downtimes w Electromagnetic compatibility (EMC) w Fluid technology w Use in potentially explosive areas Technical protective measures w Defining the safety functions w Determining the necessary level of safety Implementing the safety functions: w Designing the safety function w Creating the safety concept w Selecting the protective equipment w Positioning/dimensioning the protective equipment w Integrating the protective equipment in the control system w Product selection w Verification of the safety function w Validating all safety functions User information on residual risks User information shall not be a replacement for other measures. If the safe design or technical measures are not completely effective the user must also be warned about residual risk and informed about necessary suggestions. Overall validation of the machine As functional safety is only part of risk reduction it is necessary to evaluate all measures, that is design, technical and organisational, together in an overall validation. Placing the machine on the market After conformity has been determined during the overall validation, if necessary with the involvement of an independent body the declaration of conformity can be signed. CE marking applied to the machine while completing the technical documentation. Responsibility of the operating organisation The employer is responsible for the safety of the employee s procurement, safety inspections, training, maintenance and modifications are covered by the PUWER regulations. Check latest prices and stock 451

4 Introduction to machine safety An overview of the relevant safety standards At the moment many A- and B-type standards as well as important C-type standards are under revision. This will result in many EN standards becoming so-called EN-ISO standards. However, as a rule there is a 3-year transition period. For this reason a standard currently under revision can only actually apply in 5 or even 6 years. International Type of standard standard European standard EN Harmonised? ISO/IEC Title A B EN ISO 12100:2010 Safety of machinery. General principles for design. Risk assessment and risk reduction EN ISO ISO Risk assessment Part 1: guiding principles (previously EN 1050) Safety-related parts of control systems EN ISO ISO Part 1: General principles for design EN ISO ISO Part 2: Validation Safety of machines electro-sensitive protective equipment (ESPE) EN IEC Part 1: General requirements and tests CLC/TS IEC Part 2: Particular requirements for equipment using active opto-electronic protective devices CLC/TS IEC Part 3: Particular requirements for active opto-electronic protective devices responsive to diffuse reflection (AOPDDR) EN IEC Functional safety of electrical/electronic/programmable electronic safety related systems EN IEC Functional safety of safety related electrical, electronic and programmable electronic control systems C EN 415-X * Packaging machines (*: Only parts -1, -3 and -5 to -10 are harmonised) EN 692 Mechanical presses EN 693 Hydraulic presses Industrial robots. Safety requirements EN ISO ISO Part 1: Robot (previously EN 775) pren ISO priso Part 2: Robot system and integration (Note: EN 775 has been withdrawn, but should still be applied to robot systems until EN ISO appears.) BSI British Standards can provide detailed information on all relevant standards visit Call Blackburn or Chippenham

5 Introduction to machine safety Glossary of safety terms and abbreviations Abbreviation/ term Explanation λ Failure rate per hour λ : Failure rate per hour, sum of λs and λλd n λs: Rate of safe failures n λd: Rate of dangerous failures, can be divided into: n λdd: Rate of dangerous failures that are detected by the diagnostic functions n λdu: Rate of undetected dangerous failures β factor Is the susceptibility to common cause failures (IEC 62061/EN 62061) - See CCF AOPD Active opto-electronic A device whose sensing function is performed by opto-electronic emitting and protective device receiving elements detecting the interruption of optical radiations generated, within the device, by an opaque object present in the specified detection zone. (IEC/TS , CLC/TS ) In DIN EN 692 Mechanical presses, EN 693 Hydraulic presses and EN Hydraulic press brakes the abbreviation AOS is used as a synonym for AOPD. AOPDDR Active opto-electronic Device with a sensor function produced by opto-electronic sender & receiver elements, protective device responsive that detects the diffuse reflection of light, generated by the device, by an object to diffuse reflection in a defined two-dimensional protective field (IEC/TS , CLC/TS ) B 10d BGIA Category Number of cycles after which a dangerous failure has occurred on 10 % of the components (for pneumatic and electromechanical components) See IFA Categorisation of the safety-related parts of a control system in relation to their resistance to failures and their subsequent behaviour in the event of a failure CCF Common cause failure Common cause failure: failure of various units due to a single event where these failures are not caused by each other CENELEC Comité Européen de Normalisation Electrotechnique CLC European Committee for Electrotechnical Standardisation. Responsible for the harmonisation of electrotechnical standards within the European Union and the entire European Economic Region. See for more details Prefix for standards adopted by CENELEC. DC Diagnostic coverage Diagnostic coverage: measure of the effectiveness of the diagnostics that can be determined as the ratio of the failure rate for the detected dangerous failures to the failure rate for the total dangerous failures. d op Mean operating time in days per year E/E/PES Electrical, electronic and Electrical, electronic & programmable electronic safety-related systems programmable electronic (IEC 62061/EN 62061) safety related systems EDM External device monitoring Means by which the electro-sensitive protective equipment (ESPE) monitors the state of control devices which are external to the ESPE (IEC /EN ). The use of EDM is not limited on ESPE. EMC Electromagnetic compatibility Ability of an item of equipment to work satisfactorily in its electromagnetic environment and at the same time not to excessively interfere with this environment, in which there are other items of equipment ESPE Electro-sensitive protective Assembly of devices and/or components working together for protective tripping or equipment presence-sensing purposes and comprising as a minimum (IEC /EN ): n a sensing device n controlling/monitoring devices n output signal switching devices (OSSD) They are used to protect people at machines and systems on which there is a risk of injury. They cause the machine or system to adopt a safe state before a person can be exposed to a hazardous situation. FIT Failure in time Failure rate in 10 9 hours. λ = /h FMEA Failure mode effects analysis Failure mode and effects analysis. Procedure for the analysis of effects derived from faults (IEC 812/EN 60812). Check latest prices and stock 453

6 Introduction to machine safety Glossary of safety terms and abbreviations (continued...) Abbreviation/ term Functional safety Explanation Part of the overall safety related to the machine and the machine control system that depends on the correct function of the SRECS, on the safety-related systems in other technologies and on the external features for risk reduction HFT[n] Hardware fault tolerance Ability to continue to perform a required function in the presence of faults or failures (IEC 62061/EN 62061) h op Operating hours Mean operating time in hours per day IFA Institut für Arbeitsschutz Institute for Occupational Safety and Health of the German Social Accident Insurance. Up until 2009 BGIA. Interlocking Lambda λ An interlocking device is a mechanical, electrical or other device the purpose of which is to prevent the operation of a machine element under certain circumstances. See λ Light curtain Minimum distance Mission time An AOPD with a resolution 116 mm Calculated distance between the safeguard and the hazardous area necessary to prevent a person or part of a person reaching the hazardous area before the termination of the dangerous machine function Tm period of time covering the intended use of a SRP/CS MTTF d Mean time to failure Expectation of the mean time to dangerous failure (ISO /EN ISO ) Muting N/C N/O Temporary automatic suspension of one ore more safety function by safety-related parts of the control system (IEC /EN ) Normally Closed N/C contact Normally Open N/O contact n op Numbers of operation The mean number of annual operations (ISO /EN ISO ) per year s d op x h op x 3600 h n op = t cycle d op is the mean operating time in days per year h op is the mean operating time in hours per day t cycle is the mean time between the start of two sequential cycles of the part in seconds per cycle OSSD Output signal switching The part of the item of electro-sensitive protective equipment (ESPE) that is device connected to the machine control, and that changes to the off state when the sensor section is triggered during correct operation PDF Proximity device with defined behaviour under fault conditions PFHd Probability of dangerous Mean probability of a dangerous failure per hour (1/h) failure per hour PL Performance level Discrete level used to specify the ability of safety-related parts of control systems to perform a safety function under foreseeable conditions (ISO /EN ISO ) Positive opening Presence detection Positive opening on switches signifies that there must be positive, shape-based transmission of force between actuator and switching element. The actuating mechanism must be so designed that even on mechanical failure, e.g. on the fracture of a spring or contact welding, the contacts open reliably and remain open in the actuated state (IEC /EN ). Secondary protective device for machinery/systems that can be accessed from the floor and on which the system must be prevented from starting while the operator is in the interior (safety function: preventing start) 454 Call Blackburn or Chippenham

7 Introduction to machine safety Glossary of safety terms and abbreviations (continued...) Abbreviation/ term Protective field Reset Resolution/sensor detection capability Response delay time Response time Restart Restart interlock Safety function Safety sub-function Sensor detection capability (resolution) Explanation The area in which the test object specified by the manufacturer is detected by the item of electro-sensitive protective equipment (ESPE) Safety light curtain: The protective field lies between the sender unit and receiver unit. The field is defined by the protective field height and the protective field width. Safety laser scanner: The protective field secures the hazardous area on a machine or vehicle. The field is defined by the scanning range, scanning angle, response time and resolution of the device used (see technical specifications). Resetting the protective device to the monitored state. Manual reset is provided by a separate device to be operated manually, e.g. using a reset button. Automatic reset by the protective device is only allowed in a special case: It shall not be possible for persons to be in the hazardous area without the protective device triggered or it shall be ensured there are no persons in the hazardous area during and after reset. The limit for the sensor parameter that causes the item of electro-sensitive protective equipment (ESPE) to trigger. It is defined by the manufacturer. Time by which the response of the contacts is delayed. The times can be adjusted on switching devices with response delay. The maximum time between the occurrence of the event that caused the triggering of the sensor & the achievement of the off state at the output switching elements (OSSDs) Placing the machine back in operation. After the triggering of the protective function or after a fault, the protective device can be reset to make it possible to subsequently restart the machine. Means of preventing automatic restarting of a machine after actuation of the sensing device during a hazardous part of the machine operating cycle, after a change in mode of operation of the machine, and after a change in the means of start control of the machine (IEC /EN ). Operating modes include: inching, single stroke, automatic Start control equipment includes: foot switch, two-hand control, single break PSDI triggering or double break PSDI triggering by the ESPE s sensor function Restart interlock (RES): The machine stops and the restart interlock (RES) is engaged on interruption of at least one light beam. This interlock ensures that the machine can only be restarted if the light path is clear and the reset button has been pressed and released again. Function of a machine whose failure can result in an immediate increase of the risk(s) (EN ISO ). A safety function is provided by safety-related parts of control systems (SRP/CS). The part of a safety function that is provided by a safety-related sub-system (e.g. actuator) for risk reduction The limit for the sensor parameter defined by the manufacturer that causes the item of electrosensitive protective equipment (See ESPE) to trigger SFF Safe failure fraction Fraction of the overall failure rate of a subsystem that does not result in a dangerous failure (IEC 62061/EN 62061) SIL Safety integrity level Discrete level (one out of a possible three) for specifying the safety integrity requirements of the safety-related control functions to be allocated to the SRECS, where safety integrity level three has the highest level of safety integrity and safety integrity level one has the lowest (IEC 62061/EN 62061) SILCL SIL claim limit Safety integrity level claim limit (for a subsystem): Maximum SIL that can be claimed for a SRECS subsystem in relation to architectural constraints and systematic safety integrity (IEC 62061/EN 62061) Check latest prices and stock 455

8 Introduction to machine safety Glossary of safety terms and abbreviations (continued...) Abbreviation/ term Single break/double break PSDI mode This operating mode is advantageous if parts must be manually inserted or removed periodically. In this mode the machine cycle is automatically re-initiated after the protective field becomes clear again after one or two interruptions. The reset device is to be operated under the following conditions: on machine start on restart if the AOPD is interrupted during a dangerous movement to initiate a restart after a period of more than 30 s (cf. IEC /EN ) Further information EN 692 Nevertheless, it is necessary to check that the operator cannot be placed at risk during the working process. This situation limits use to small machines on which the hazardous area cannot be entered and there is point-of-operation protection. All other sides of the machine must also be protected using suitable measures. If this operating mode is used, the resolution of the AOPD must be less than or equal to 30 mm (cf. EN ISO 13855, also EN 692, EN 693). In general the following errors must be excluded when mounting protective devices: reaching over, reaching under, reaching around, standing behind. SRECS Safety-related electrical Electrical control system for a machine the failure of which will result in an immediate control system increase in the risk or risks SRP/CS Safety-related part(s) of Part of a control system that responds to safety-related input signals and generates control system safety-related output signals (ISO /EN ISO ) T 10d Mission time Test rod Explanation Limit for the operating time of a component. Mean time until a dangerous failure has occurred on 10% of the components. B 10d T 10d = nop The MTTFd determined for components subject to wear only applies for this time. Tm period of time covering the intended use of a SRP/CS An opaque cylindrical element used to verify the detection capability of the active opto-electronic protective device (AOPD) (IEC/TS , CLC/TS ) VBPD Visual based protection device Protective devices based on image evaluation, e.g. safety camera systems 456 Call Blackburn or Chippenham

Introduction to machine safety

Introduction to machine safety www.lcautomation.com A practical approach to machinery safety.......... 424 Overview of relevant standards................. 426 Glossary of abbreviations and terminology......... 428 A practical approach