Table of Contents
Introduction to the Concept of Performance Level
In today’s rapidly evolving world of industrial automation, the concept of Performance Level: Key to Machine Safety plays a pivotal role in ensuring the safety of machinery and equipment. Performance Level (PL) measures a system’s capability to achieve a specified safety level, minimizing the risk of failures and accidents. Within the context of the Machinery Directive 2006/42/EC, harmonized standards like PN-EN ISO 13849-1:2023-09 define the general design principles that must be met for machines to receive the CE mark. Performance Level is a critical component of these standards, influencing every aspect of machine design, auditing, and safety management.
Introduction to Standard PN-EN ISO 13849-1:2023-09
The PN-EN ISO 13849-1:2023-09 standard is a key document in machinery safety, outlining requirements for the design, implementation, and evaluation of safety-related control systems. Its main goal is to ensure these systems meet appropriate reliability and functionality levels, minimizing the risk of failures that could pose threats to operators and the work environment. This standard is harmonized with the Machinery Directive 2006/42/EC, making compliance crucial for obtaining CE marking for machines and equipment introduced to the European market.
Core Concepts and Scope of the Standard
The PN-EN ISO 13849-1:2023-09 standard defines Performance Level (PL) as the degree of capability of a system to achieve a specified safety level, measured in five categories from PL a to PL e, with PL e being the highest safety level. Performance Level depends on several factors, including system architecture, diagnostics, and component reliability.
The standard covers a broad range of aspects related to the design and evaluation of safety-related control systems, including:
- Risk Analysis: Identifying and assessing potential hazards associated with machine operation.
- Safety Requirements Specification: Defining the safety function requirements that the control system must meet.
- Control System Design: Creating and implementing systems that comply with a specified Performance Level.
- Evaluation and Verification: Conducting tests and analyses to confirm that systems meet the standard’s requirements.
Risk Analysis and Safety Requirements Determination
The first step in complying with the PN-EN ISO 13849-1:2023-09 standard is conducting a detailed risk analysis. This analysis aims to identify potential hazards and assess the risk associated with each hazard. Based on the risk analysis results, safety requirements for control systems are determined.
Control System Design
Designing control systems compliant with PN-EN ISO 13849-1:2023-09 involves several key stages, including:
- Defining Safety Functions: Determining which control functions are critical for safety and what their requirements are.
- Component Selection: Choosing appropriate components that meet reliability and diagnostic requirements.
- System Architecture: Designing the control system structure, considering redundancy and diagnostics.
- Reliability Calculations: Performing reliability calculations, such as Mean Time to Failure (MTTF) and Mean Time to Repair (MTTR), to determine the overall Performance Level of the system.
Implementation and Integration
After designing the control system, the next step is its implementation and integration with the machine. This stage includes:
- Component Installation: Assembling selected components according to the design.
- System Integration: Connecting different parts of the control system, ensuring their cooperation and compatibility.
- Functional Testing: Conducting functional tests to ensure the system operates according to design assumptions.
Verification and Validation
A key element of compliance with the PN-EN ISO 13849-1:2023-09 standard is the verification and validation process, which includes:
- Design Verification: Checking whether the control system design meets all specified requirements.
- Validation Tests: Conducting validation tests, including simulations and practical tests, to ensure the system operates according to Performance Level requirements.
- Documentation: Preparing detailed documentation containing test results and analyses, confirming system compliance with the standard.
Example Calculations for PL e and PL c
Calculations for Performance Levels PL e and PL c are crucial to ensuring that safety-related control systems meet required reliability standards. Below are examples of calculations for both performance levels.
Example 1: Calculations for PL e
System Description:
- Control system of a production machine with an emergency stop function (E-Stop).
- Architecture: category 4, with dual-channel and monitoring.
- Required to achieve PL e.
Calculation Steps:
- Determine system components:
- Two E-Stop buttons (dual-channel).
- Two safety relays.
- PLC controller with safety functions.
- Mean Time to Dangerous Failure (MTTFd):
- Each E-Stop button has MTTFd = 100 years.
- Each safety relay has MTTFd = 50 years.
- PLC controller has MTTFd = 30 years.
- Diagnostic Coverage (DC):
- Diagnostic coverage for category 4 is 99% (0.99).
- Common Cause Failure (CCF) factor:
- CCF value for category 4 is at least 65%.
- Calculate MTTFd of the entire system:
- E-Stop buttons (dual-channel): 1 / (1 / 100 + 1 / 100) = 50 years.
- Safety relays: 1 / (1 / 50 + 1 / 50) = 25 years.
- PLC controller: 1 / (1 / 30 + 1 / 30) = 15 years.
- Calculate system MTTFd:
- Combination of all elements: 1 / (1 / 50 + 1 / 25 + 1 / 15) = 9.68 years.
- Calculate PFH (Probability of dangerous Failure per Hour):
- PFH for PL e must be below 10-8 per hour.
- Using MTTFd and DC values:
PFH = 1 / (MTTFd * 365 * 24) * (1 – DC) = 1 / (9.68 * 365 * 24) * (1 – 0.99) = 1.18 * 10-8
Conclusion: The system does not achieve PL e because the calculated PFH does not meet the required value for PL e.
Example 2: Calculations for PL c
System Description:
- Control system of a machine with a safety guard control function.
- Architecture: category 2, with periodic monitoring.
- Required to achieve PL c.
Calculation Steps:
- Determine system components:
- Safety guard with position sensor.
- Safety relay.
- PLC controller with safety functions.
- Mean Time to Dangerous Failure (MTTFd):
- Safety guard: MTTFd = 20 years.
- Safety relay: MTTFd = 50 years.
- PLC controller: MTTFd = 30 years.
- Diagnostic Coverage (DC):
- Diagnostic coverage for category 2 is 90% (0.90).
- Calculate MTTFd of the entire system:
- Safety guard: MTTFd = 20 years.
- Safety relay: MTTFd = 50 years.
- PLC controller: MTTFd = 30 years.
- Calculate system MTTFd:
- Combination of all elements: 1 / (1 / 20 + 1 / 50 + 1 / 30) = 10.64 years.
- Calculate PFH (Probability of dangerous Failure per Hour):
- PFH for PL c must be below 10-6 per hour.
- Using MTTFd and DC values:
PFH = 1 / (10.64 * 365 * 24) * (1 – 0.90) = 1.08 * 10-6
Conclusion: The system does not achieve PL c because the calculated PFH does not meet the required value for PL c.
Comparison with Standard PN-EN IEC 62061:2021-12
The PN-EN 62061 standard, concerning the functional safety of electrical, electronic, and programmable control systems related to safety, is often compared with PN-EN ISO 13849-1:2023-09. Both standards aim to ensure machine safety but differ in approach and scope.
- Scope: PN-EN IEC 62061:2021-12 focuses mainly on electrical, electronic, and programmable systems, while PN-EN ISO 13849-1:2023-09 covers a broader range of technologies, including mechanical and hydraulic.
- Level of Detail: PN-EN 62061:2008 is more detailed in technical requirements for electronic systems, while PN-EN ISO 13849-1:2023-09 offers a more general approach applicable to various technologies.
- Risk Assessment: Both standards require risk analysis, but PN-EN IEC 62061:2021-12 emphasizes detailed risk assessment and control measures in programmable systems.
| Criterion | PN-EN ISO 13849-1:2023-09 | PN-EN 62061:2008 |
|---|---|---|
| Scope | Mechanical, electrical, electronic, and programmable safety-related control systems | Electrical, electronic, and programmable safety-related control systems |
| Risk Approach | Defining Performance Levels (PL) and their application in system design | Defining SIL levels and their application in system design |
| System Architecture | Categories from 1 to 4 with varying levels of redundancy and diagnostics | Control system architectures according to SIL levels |
| Mean Time to Failure (MTTF) | Required calculations to determine component MTTF | Required calculations to determine component MTTF |
| Diagnostics | High diagnostic requirements for achieving high PL levels | Various diagnostic requirements depending on SIL level |
| Certification | Harmonized with Machinery Directive 2006/42/EC | Harmonized with Machinery Directive 2006/42/EC |
The Role of Performance Level in Industrial Automation
Performance Level is an indispensable element in the automation of production processes, where precision and reliability are crucial. Implementing an appropriate Performance Level in machine control systems directly affects their efficiency and operational safety. An example of Performance Level application is in the design of production lines, where each machine must meet specific safety requirements to ensure the smooth and fault-free operation of the entire production process. Automation of production processes requires not only efficiency but also compliance with safety standards, achieved through a properly defined Performance Level.
Safety Audit and Performance Level
A safety audit is a process that evaluates the compliance of machines with safety standards, including Performance Level. Industrial automation integrators play a crucial role in conducting such audits, ensuring that systems meet the highest safety standards. Performance Level is assessed based on risk analysis and functional tests, verifying whether control systems operate according to design assumptions and standards. A safety audit may also include technical documentation analysis, conducting verification tests, and inspecting machines to identify potential hazards.
Designing Machines According to Performance Level Requirements
Machine design requires considering various mechanical and electronic aspects to meet Performance Level requirements. Mechanical systems, such as pneumatic and hydraulic systems, must be carefully calculated for strength to ensure their reliability and safety under different operating conditions. Electronic systems, in turn, must ensure reliability and functional safety, which is particularly important in control systems. Performance Level defines the minimum requirements that control systems must meet to minimize failure risk. In design, a design office also considers harmonized standard requirements, such as PN-EN ISO 13849-1:2023-09 and PN-EN 62061:2008, which specify requirements for both system types, ensuring a comprehensive approach to machine safety.
Machine CE Certification and Performance Level
The PN-EN ISO 13849-1:2023-09 standard specifies requirements for CE certification of machines, focusing on safety aspects related to Performance Level. CE certification is essential for machines to be legally marketed within the European Union. The PN-EN 62061:2008 standard, which also concerns functional safety, introduces additional requirements for electronic and programmable systems, increasing the complexity of the certification process. Both standards are harmonized with the Machinery Directive 2006/42/EC, meaning that meeting their requirements ensures compliance with European safety regulations.
Performance Level and Machine Adaptation to Minimum Requirements
Adapting machines to minimum requirements compliant with Performance Level requires precise procedures and regular audits. Practical examples show how these procedures are applied in various industries, ensuring safety and regulatory compliance. Performance Level is a crucial element in the process of machine modernization, where existing equipment is adapted to new safety standards. This process includes risk analysis, adapting existing control systems, and conducting tests and verification to ensure that machines meet current safety requirements. Adapting machines to minimum requirements according to Performance Level is essential for ensuring their safe and efficient operation.
Significance for Industry 4.0
The PN-EN ISO 13849-1:2023-09 standard is crucial in the context of Industry 4.0, characterized by a high degree of automation and system integration. Within Industry 4.0, control systems must be not only reliable but also flexible and scalable to meet dynamically changing production requirements. The Performance Level defined in the PN-EN ISO 13849-1:2023-09 standard ensures that control systems are designed with the highest safety standards in mind, which is essential in complex and automated production environments.
Performance Level: Summary
The PN-EN ISO 13849-1:2023-09 standard is a key document in ensuring the safety of machines and control systems. By complying with it, companies can be confident that their control systems meet the latest safety requirements, minimizing the risk of failures and accidents. Performance Level is a central element of this standard, defining requirements for control system reliability and functionality. Adhering to the PN-EN ISO 13849-1:2023-09 standard is essential for obtaining the CE mark and ensuring that machines introduced to the European market are safe for users and the work environment.
Performance Level: FAQ
Performance Level (PL) is a measure of a control system’s ability to achieve a specified safety level. It is defined in five levels from PL a to PL e, with PL e representing the highest safety level.
PN-EN ISO 13849-1 covers a wide range of control systems (mechanical, electrical, electronic, programmable), whereas PN-EN 62061 focuses on electrical, electronic, and programmable control systems.
PN-EN ISO 13849-1 is applied when designing safety-related control systems for machines, including mechanical, electrical, electronic, and programmable components.
Performance Level (PL) is used in the PN-EN ISO 13849-1 standard and includes five safety levels, while Safety Integrity Level (SIL) is used in the PN-EN 62061 standard and includes three safety levels (SIL 1 to SIL 3).
To achieve Performance Level PL e, conduct a detailed risk analysis, design the system with appropriate redundancy and diagnostics, and perform thorough testing and validation.
Yes, both PN-EN ISO 13849-1 and PN-EN 62061 require detailed risk analysis to determine control system safety requirements.
Machines must meet the PN-EN ISO 13849-1 standard and comply with the Machinery Directive 2006/42/EC to receive CE certification.
Yes, both standards are harmonized with the Machinery Directive 2006/42/EC, meaning their compliance is crucial for obtaining CE certification.
Diagnostic coverage (DC) is crucial for determining safety levels. In PN-EN ISO 13849-1, diagnostic requirements vary for different PL levels, while in PN-EN 62061, they are defined for SIL levels.
Specialized software tools, such as SISTEMA, support risk analysis and calculations for achieving the appropriate Performance Level or SIL in control systems.