EN ISO 13849-1: Safety of machinery - Safety-related parts of control systems - Part 1: General principles for design
EN ISO 13849-1 provides instructions for system design, integration and validation. The standard can be used for the safety-related parts of control systems and various kinds of machinery, regardless of the technology or energy source used. It also includes special requirements for safety-related parts that have programmable electronic systems. This standard thus covers the entire safety function for all included devices (i.e. a complete safety chain such as sensor-logic-actuator).
EN ISO 13849-1 defines how to determine the required Performance Level (PL) and how to verify the achieved PL within a system. PL describes how well a safety system is able to perform a safety function under foreseeable conditions. Five possible PLs are available: a, b, c, d and e. PL “e” has the highest safety reliability while PL “a” the lowest.
The standard has replaced EN 954-1:1996 since 1 January 2012.

EN ISO 13849-2: Safety of machinery - Safety-related parts of control systems - Part 2: Validation
EN ISO 13849-2 specifies the procedures and conditions to be followed for the validation by analysis and testing of the specified safety functions, the category achieved, and the performance level achieved by the safety-related parts of a control system (SRP/CS) designed in accordance with EN ISO 13849-1.

EN 62061: Safety of machinery - Functional safety of safety-related electrical, electronic and programmable electronic control systems
EN 62061 is the standard for designing electrical safety systems. It includes recommendations for the design, integration and validation of safety-related electrical, electronic and programmable electronic control systems for machinery. It describes the SRECS using the Safety Integrity Level (SIL) as EN 61508 but only until SIL3. The entire safety chain is covered.

EN 61511-1, 2, 3: Functional safety - Safety instrumented systems for the process industry sector
EN 61511 series offers significant value to operators and integrators in the process industry. It sets out practices in the engineering of systems that ensure the safety of an industrial process using instrumentation. Such systems are referred to as Safety Instrumented Systems (SIS). A SIS is composed of any combination of sensor(s), logic solver(s) and final element(s).

EN 50495: Safety devices required for the safe functioning of equipment with respect to explosion risks
EN 50495 defines with SIL the required safety level for monitoring of potential ignition sources of electrical explosion protected equipment and the requirements on the safety level of the respective safety devices. The standard offers a simplified evaluation procedure for hardware reliability for non-complex safety equipment as well.