Maintenance teams use two phrases that sound alike: safety component and safety-relevant part. Only the first is a legal term, and it decides what a spare has to arrive with.
What the law means by a safety component
The Machinery Directive 2006/42/EC defines a safety component in Article 2(c). A part is one when all four conditions hold:
- it serves to fulfil a safety function;
- it is placed on the market on its own;
- its failure or malfunction endangers the safety of persons;
- it is not necessary for the machine to function, or normal components can replace it for the machine to function.
The last condition is the one people forget. A light curtain qualifies: the press runs without it, and that is exactly the danger. A motor does not, because the machine cannot run without it.
Safety component or safety-relevant part
Safety-relevant is a working term, not a legal one. It covers every part whose failure affects a safety function on your machine. A standard contactor that switches off a motor when a guard opens is safety-relevant, because the stop depends on it. It is still a normal component from the standard range, and its role comes from how the machine builder used it.
Which parts are safety-relevant on a given machine is written in its own documentation: the risk assessment, the list of safety functions, the circuit diagrams and the validation report. That file, not the part’s catalogue entry, tells you what a replacement must match.
Examples from the directive’s list
Annex V of the Directive gives an indicative list of safety components. Among them are parts a maintenance team replaces in practice:
- protective devices that detect the presence of persons, such as light curtains, laser scanners and safety mats;
- logic units that ensure safety functions, such as safety relays and safety controllers;
- emergency stop devices;
- two-hand control devices;
- valves with additional means of failure detection that control dangerous movements.
What a safety component must arrive with
Because it is placed on the market on its own, a safety component carries its own CE marking and its manufacturer’s EU declaration of conformity, and its instructions state the safety function, the performance level or SIL it reaches and the conditions for reaching it. For a spare, ask for:
- the full order number and the hardware revision, matching the machine’s documentation;
- the declaration of conformity for that type;
- new or new surplus condition in original packaging, unless the refurbisher is the manufacturer or its authorised service partner;
- the date code, so you know how much of the rated lifetime is left.
The guide to safety parts and certifications explains PL and SIL ratings, the rules for buying safety parts on the secondary market, and why the safety function has to be validated again after a replacement. The counterfeit checks matter twice as much here.
What changes in 2027
The Machinery Regulation (EU) 2023/1230 replaces the Directive and applies from 20 January 2027. It keeps the idea of a safety component and states that it can be a physical or a digital component, including software. For spare parts the practical rule stays the same: like for like, with documents, and a validated safety function afterwards.