EN 13849-1 evaluation

EN ISO 13849-1 is the main standard for the design of safety-related control systems in the machinery safety department. The standard is now supplemented by FDAM (Final Revised Draft of International Standard) and FprA (Final Revised Draft of European Standard).

The main changes are as follows: Regarding the control system category used to determine the performance level PL , the potential and effective value of the PL of the 4 types of systems mean time to dangerous failure ( MTTFd ) has been increased from the current 100 years to 2500 years. This means that more subsystems can be integrated in the safety function than before. This is particularly beneficial for systems with multiple security functions. For hydraulic components, the MTTFd value may reach 1200 years in the future , depending on the number of annual operations. Another new development involves category 2 systems, which were previously envisaged to test frequency a hundred times higher than the required safety function. It is now possible to test immediately before or when a safety function is required to be performed, provided that the safety system's response speed is sufficient to protect the operator.

Added "Overlapping Hazards" section: In order to quantify the risks, each hazard can be considered individually, for example in a work area that does not overlap with the work area. Only when there are multiple risks at the same place at the same time, different risks need to be considered together. According to the current technical level, the core aspect of the future standard will include determining the overall failure probability of the safety function by adding up the various PHF values of the subsystem .

Other changes involve the description of parameters F and P when assigning risks to corresponding performance levels . The "new" 13849-1 was released as a unified version of the ISO standard at the end of 2015 , and will be introduced into the European standard as an EN standard in early 2016 .

The myocardial infarction rating ( PL ) system of EN ISO 13849-1 is based on quantification. Allegedly, the standard setters determine the use of quantitative methods, so that megabytes can be compared with the safety integrity level ( SIL ) system used for hazards , providing a basis for the verification requirements of EN ISO 13849-2 . According to this system, engineers can calculate the performance level of control-related safety components ( SPR/CS ) for each designated safety function. First, qualitative analysis needs to be used to determine the required performance level ( PLr ) for each safety function . EN ISO 13849-1 includes the following clauses:

4.3 determining the desired performance level ( the PLr ) - such as EN ISO 13849-1 of 4.3 articles mentioned, the amount of analyte is determined using each safety function and performance level ( the PLr ).

4.3 Determine the learned performance level ( PLr ) - For each specified safety function performed by the SRP/CS , the required performance level ( PLr ) needs to be determined and filed.

Risk assessment can determine the required performance level, but also determines the amount of risk that needs to be reduced in the safety-related parts of the control system. The greater the amount of risk that needs to be reduced by SRP/CS , the higher the value of PLr . In the figure below, three issues that need to be considered in the qualitative analysis process are described: the severity of the injury, the frequency of exposure to danger, and the probability of avoiding the danger. The new standard stipulates that the calculated PL must be greater than or equal to PLr .