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Functional Safety

Compliance of safety related controls can be a complex and challenging aspect of machinery safety. Product Compliance Support can support you through the whole process or just part of it.

Areas we can assist are:

Deliverables:

Key deliverables we can offer are:

Background:

The Machinery Directive and The Supply of Machinery (Safety) Regulations 2008 (UK domestic legislation) requires that machinery can be operated, adjusted, and maintained without putting persons at risk.

A key part of these regulations include requirements for machinery controls. Specifically, clause 1.2.1 – ‘Safety and reliability of control systems’ requires that design and construction of the machine prevents hazardous situations arising from the following:          

EN ISO 13849-1 (previously EN954-1) is an international harmonised standard that was introduced in 1995 to give specific guidance and a methodology for these topics and is central to functional safety compliance of machinery.

The standard provides a framework for ensuring that each safety related function has the appropriate level of reliability relative to the level of risk that the function is protecting from. It also provides a methodology for specification, design and validation to prevent unwanted errors arising throughout the implementation process.

Other functional safety standards exist for sectors such as rail (EN 50128), nuclear (IEC 61513) and the process industry (IEC 61511). These standards are derived from parent standard IEC61508. These standards were developed in parallel with machinery functional safety, however many of the principle adopted for machinery were born out of these requirements.

ISO 13849-1 for machinery, has evolved considerably since its introduction. It now adopts a similar quantitative approach to these other functional safety standards whilst still retaining the original concept of ‘Categories’ as means of circuit structure evaluation.

Scope:

As part of the risk reduction process defined in ISO12100:2010, ISO1389-1 should be applied whenever a safety function and its corresponding safety system are used to provide risk reduction.

Functional safety and ISO 13849-1 applies to virtually all machines from simple equipment with a single emergency stop button to large complex assemblies with multiple safety functions and operating modes.

Safety related parts of the control system (SRP/CS) and their subsystems include all devices required to carry out the safety function regardless of energy form (e.g. electrical, pneumatic and hydraulic). This can include power actuators such contactors, valves and inverter drives as well as safety input and logic devices such as safety switches, light curtains and safety relays.

Users of machinery already placed on the market are also subject to the Use of Equipment Directive OR Provisions and Use of Work Equipment Regulations/PUWER (GB domestic legislation). Safety systems should also be evaluated under ISO 13849-1 according the HSE Approved Code of Practice (ACOP) guidance when complying with Regulation 18 ‘Control Systems’.

Requirements