What is NEN-EN-ISO 13850?
NEN-EN-ISO 13850 is the Dutch edition of the international standard ISO 13850:2015, which sets out the functional requirements and design principles for the emergency stop function on machinery, regardless of whether the hazardous motion is driven electrically, hydraulically, pneumatically or mechanically. The standard describes what an emergency stop must do, what the actuator looks like, where it is placed and how disengaging and resetting work. The electrical implementation is covered by IEC 60204-1, and the reliability of the stop chain by ISO 13849-1 or IEC 62061.
Applying EN ISO 13850 gives a presumption of conformity with essential requirement 1.2.4.3 of the Machinery Directive. The standard itself is voluntary, but for manufacturers it is the usual route to a demonstrably correct emergency stop, to compliance and therefore to CE marking.
🧠 What exactly does NEN-EN-ISO 13850 govern?
The standard was prepared by ISO/TC 199 Safety of machinery in collaboration with CEN/TC 114 and runs to only eleven pages. Within the ISO 12100 hierarchy it is a type-B2 standard: a generic standard on one type of safeguard that applies to almost all machinery. A type-C standard for a specific machine (for example a press or a robot cell) takes precedence where it requires something different.
The key requirements in clause 4:
- Always available - the emergency stop function works in every operating mode and overrides all other functions, without disabling other protective functions.
- A single human action - one deliberate action (pressing, pulling, stepping) is enough to initiate the function.
- As fast as possible, without new hazards - the hazardous motion stops in the most appropriate way, as stop category 0 or 1 according to IEC 60204-1.
- Latching - after actuation the actuator stays in the stop position until it is disengaged manually at the device itself.
- No restart on disengagement - unlatching or resetting only makes a new, deliberate start command possible.
- Clear span of control - the user must be able to see which part of the installation an emergency stop shuts down.
What the standard deliberately does not cover: reversing or limiting motion, shielding, braking or disconnecting energy. Those functions can be part of the emergency stop function, but they fall under other standards. Excluded are machines where an emergency stop would not reduce the risk, and hand-held or hand-operated machines.
🔧 Which requirements apply to the emergency stop actuator?
Clauses 4.3 to 4.6 deal with the physical actuator. It does not have to be a push-button: a pull-cord, bar, handle or foot pedal without a protective cover is also allowed.
| Topic | Requirement in ISO 13850:2015 | Practical example |
|---|---|---|
| Colour | Red actuator, background yellow as far as practicable | Red mushroom-head button on a yellow label or yellow enclosure |
| Contact operation | Electrical device with mechanical latching to IEC 60947-5-5, contacts with direct opening action | The button mechanically forces open even a welded contact |
| Accessibility | Reachable quickly and safely from every location where it is needed | Emergency stop at every operator station and along long conveyors |
| Pull-cord | Works when pulled and when the cord breaks or goes slack, cord clearly visible | Rope-pull switch along a conveyor with supports at fixed intervals |
| Unintended actuation | Prevent it without impairing accessibility | Collar around the button, never a lockable cover |
| Portable control stations | Avoid confusion between active and inactive emergency stops | Store a disconnected or wireless pendant out of sight |
| Environment | Withstand local vibration, moisture, dirt and temperature | Enclosure with a suitable IP rating in wet or dusty areas |
Red on yellow is reserved for emergency stops. An ordinary stop button, or the button on a switched-off HMI panel, must therefore not look like that, because an operator in a panic would press a button that does nothing.
🔄 How does ISO 13850 relate to other machinery standards?
ISO 13850 defines the what, but refers to other standards for the how. Together they form a single chain:
| Standard | Role for the emergency stop |
|---|---|
| ISO 12100 | Risk assessment: is an emergency stop needed and which stop is appropriate? |
| NEN-EN-ISO 13850 | Function, appearance, placement, disengagement and reset |
| IEC 60204-1 | Electrical implementation, stop categories 0 and 1, emergency stop versus emergency switching off |
| ISO 13849-1 / IEC 62061 | Required reliability as a PL or SIL |
| IEC 60947-5-5 | Construction of electrical emergency stop buttons with latching |
| ISO 4413 / ISO 4414 | Emergency stop in hydraulic and pneumatic systems |
The required safety level follows from the risk assessment, not from a fixed value per machine. For the 2015 edition, PLr c or SIL 1 is generally taken as the minimum, and machines with a risk of serious, irreversible injury often end up at PL d. The logic is usually implemented with a dual-channel safety relay or a Safety PLC.
📅 Which editions of ISO 13850 exist?
The standard has a long history. Europe first had EN 418 (1992), after which ISO published the first edition of ISO 13850 in 1996. The second edition appeared in 2006 and was adopted in Europe as EN ISO 13850:2008.
The current, third edition is ISO 13850:2015, published on 1 October 2015. CEN approved the text unchanged on 5 September 2015 as EN ISO 13850:2015, which replaced EN ISO 13850:2008; national standards bodies had to adopt it by May 2016. NEN published the Dutch edition as NEN-EN-ISO 13850:2015. New in this edition are, among other things, explicit requirements for portable and cableless operator control stations and for resetting them.
In late September 2026 CEN/TC 114 approved a new project to revise the standard. Until a new edition is published, the 2015 version remains the benchmark. From 20 January 2027 the Machinery Regulation (EU) 2023/1230 replaces the Machinery Directive; the emergency stop requirement remains essentially the same.
🏭 Where do you apply ISO 13850 in industrial automation?
In industrial automation the standard applies wherever people work near moving parts:
- Machines with moving parts - presses, packaging machines, robots and cobots, conveyors
- Panel building - emergency stops in the door of the control cabinet, on operator stations and on HMI panels
- Production lines - linked machines where it must be clear, zone by zone, what each emergency stop shuts down
- Mobile and portable control - teach pendants and wireless remote controls for cranes and robots
Step-by-step approach to a compliant emergency stop
- Establish the need - record in the risk assessment whether an emergency stop reduces the risk and which stop category fits.
- Determine the required level - derive the PLr with ISO 13849-1 or the SIL with IEC 62061.
- Select and place the actuators - an emergency stop at every operator station and wherever the risk assessment requires one; pull-cords along long lines.
- Define the span of control - on linked machines, mark for each emergency stop which zone it stops.
- Design the stop chain - usually dual-channel, with fault detection, fail-safe and separate from the normal stop and from interlocks.
- Validate and document - test every emergency stop, check the stopping time and include the function in the technical file.
An emergency stop is a complementary protective measure. It never replaces guards, interlocks or safe isolation during maintenance: anyone working inside the machine isolates the energy through a work permit and a lockout procedure, not by pressing an emergency stop.
🔐 How do you keep the emergency stop effective in daily practice?
ISO 13850 is aimed at the manufacturer, but the employer must make sure the emergency stop keeps working. For safety at work in the Netherlands this follows from the Arbowet and the Working Conditions Decree, and it comes back in the risk inventory and evaluation:
- Test periodically - an emergency stop that is never operated can fail unnoticed; test every actuator on a fixed schedule.
- Organise resetting deliberately - the reset belongs in a position with a view of the danger zone, as ISO 13849-1 requires for manual reset.
- Control changes - anyone modifying safety code in a Safety PLC re-checks it against the risk assessment.
- Networks and wireless - for emergency stops over a fieldbus (such as PROFIsafe) or wireless links, communication must be fail-safe; a lost connection results in a stop.
- Train and record - operators know where the emergency stops are and what they shut down; this belongs in instruction and training.
During an internal audit or inspection, an emergency stop that is hard to reach, wrongly coloured or not working stands out immediately. Such a finding calls for immediate action, because work equipment with a faulty emergency stop no longer complies with the Working Conditions Decree.
❓ Frequently asked questions
Is NEN-EN-ISO 13850 mandatory?
NEN-EN-ISO 13850 is a harmonised standard and therefore formally voluntary. Applying it gives a presumption of conformity with the emergency stop requirement of the Machinery Directive. If you choose another solution, you must demonstrate yourself that it meets essential requirement 1.2.4.3.
What is the difference between ISO 13850 and IEC 60204-1?
ISO 13850 describes the emergency stop function independently of the type of energy: what it must do, what it looks like and how resetting works. IEC 60204-1 describes the electrical implementation, such as stop categories and the difference between emergency stop and emergency switching off. For an electrically driven machine you therefore apply both standards.
Which edition of ISO 13850 is current?
The current edition is ISO 13850:2015, the third edition, adopted in Europe as EN ISO 13850:2015. It replaced ISO 13850:2006 and EN ISO 13850:2008. CEN started a revision in 2026, but the 2015 edition remains valid until a new one is published.
Which Performance Level does an emergency stop need?
The required Performance Level follows from the risk assessment under ISO 13849-1 or IEC 62061, not from a fixed value per machine. For the 2015 edition of NEN-EN-ISO 13850, PLr c or SIL 1 is generally taken as the minimum. Where there is a risk of serious injury, an emergency stop often ends up at PL d.
May an emergency stop restart the machine when it is released?
No, under NEN-EN-ISO 13850 disengaging or resetting an emergency stop must never restart the machine. Disengagement is done manually at the actuator and only enables a new, separate start command. This is how the standard prevents a machine from starting unexpectedly.
Does ISO 13850 apply to hand tools?
No, NEN-EN-ISO 13850 excludes hand-held and hand-operated machines, as well as machines where an emergency stop would not reduce the risk. For such machines the normal operating switch is usually sufficient. The risk assessment under ISO 12100 records that decision.
📌 In summary
NEN-EN-ISO 13850 is the type-B2 standard that defines how the emergency stop on a machine works, looks, is placed and is reset, independently of the type of energy. Together with IEC 60204-1 for the electrical implementation and ISO 13849-1 or IEC 62061 for reliability, the 2015 edition is the standard route to designing an emergency stop that demonstrably conforms to the Machinery Directive and, soon, the Machinery Regulation.