Safety of machinery - Emergency stop - Principles for design (ISO 13850:2006); English version of DIN EN ISO 13850:2008-09
1Key Takeaways
This International Standard specifies functional requirements and design principles for the emergency stop function on machinery, independent of the type of energy used to control the function. It is applicable to all machinery except for: -- machines in which the provision of emergency stop would not lessen the ris…
2Expert Interpretation
The DIN EN ISO 13850:2008 standard specifies in detail the safety requirements and design principles for emergency stop functions on machinery, covering stop category selection, equipment configuration, operating conditions, and environmental influencing factors, providing machinery manufacturers with safety design guidance that complies with the EU Machinery Directive.
Standard Overview and Development Background
DIN EN ISO 13850:2008-09, "Safety of Machinery — Emergency Stop — Design Principles," is a Category B2 safety standard developed by ISO/TC 199, "Safety of Machinery," of the International Organization for Standardization. It officially came into effect on September 1, 2008. This standard supersedes DIN EN ISO 13850:2007-03, published in March 2007, and simultaneously repeals DIN EN 418, published in January 1993.
As an EU harmonized standard, this standard specifies the relevant requirements in Annex I of the EU Machinery Directive 98/37/EG (valid until December 28, 2009) and the new Machinery Directive 2006/42/EG (effective from December 29, 2009). When this standard is designated as a harmonized standard in the Official Journal of the European Communities, manufacturers can use it to gain a presumption of conformity with the requirements of the Machinery Directive.
Analysis of Core Safety Requirements
Emergency Stop Function Basic Characteristics
The standard defines the emergency stop function as a core characteristic of a safety function: it must be readily available and functional, have the highest priority in all machine operating modes, and must not affect the means for rescuing trapped persons. This function is intended to avoid or reduce danger to persons, machinery, or ongoing work through a single human action.
Technical requirements for stop categories
| Stop category | Stop method | Energy supply | Applicable scenarios |
|---|---|---|---|
| Category 0 | Immediate stop, by interrupting the energy supply or mechanical separation | Complete disconnection | High-risk emergency, requiring immediate cessation of all motion |
| Category 1 | Controlled stop, first reach the stop state and then interrupt the energy | Disconnection after stopping | The stopping process needs to be controlled to avoid secondary risks |
The choice of stop category must be based on the machine risk assessment, please refer to IEC 60204-1:2005, Section 9.2.5.4.2.
Emergency Stop Device Design Specifications
Device Types and Installation Requirements
Types of operating elements permitted by the standard include mushroom pushbuttons, wires, ropes, rails, handles, and, in special applications, unshielded foot switches. Emergency Stop Devices must be installed at every operator station unless a risk assessment indicates otherwise. In addition, Emergency Stop Devices must be installed at additional locations determined by the risk assessment.
Operation and Reset Mechanisms
Emergency Stop Devices must utilize a direct operation principle with a mechanical locking feature. Electrical Emergency Stop Devices must comply with IEC 60947-5-5. Reset operations may only be performed at the location where the Emergency Stop was triggered, and resetting must not restart the machine; it must only allow restart.
Marking and Color Specifications
Emergency stop operating elements must be red. If the operating element has a background and is feasible, the background must be yellow. The marking must use the symbol (5638) of IEC 60417-DB:2002-10.
Special Requirements for Wires and Ropes as Operating Elements
When wires and ropes are used as operating elements for emergency stop devices, they must be easy to operate. The design must take into account: the deflection required to generate the emergency stop command, the maximum possible deflection, the minimum distance between the wire or rope and surrounding objects, visibility for operators (e.g., by using flags), and the force required to operate the control device and its direction.
Measures must be taken to prevent hazards caused by wire or rope breakage or unhooking. The reset device must be arranged so that the entire length of the wire or rope is visible from the reset device. The user information must specify that the cause of the operation must be checked along the entire length of the wire or rope after operation and before resetting.
Recommendations for Standard Implementation and Risk Assessment
Key Elements of Risk Assessment
When implementing the DIN EN ISO 13850 standard, a comprehensive risk assessment must be conducted, focusing on:
| Assessment dimensions | Specific content | Standard references |
|---|---|---|
| Hazard identification | Functional abnormality, material properties, human error, normal operation | Comments to Article 3.1 |
| Stop category selection | Determine Category 0 or Category 1 based on risk level | Article 4.1.5 |
| Equipment layout | Operator station location, additional location, and accessibility | Clause 4.4.2 |
| Environmental adaptability | Vibration, shock, temperature, dust, humidity, etc. | Clause 4.3 |
Technological Evolution and Standard Updates
Compared to the 2007 version, the main updates to DIN EN ISO 13850:2008-09 include the addition of an informative Annex ZB on the relationship between this European standard and the essential requirements of the Machinery Directive 2006/42/EG. This update reflects the development of the EU machinery safety regulatory system and provides manufacturers with clearer guidance on legal compliance.
Harmonization with other standards
As a Category B2 standard, the provisions of this standard can be supplemented or modified by Category C standards. When the provisions of the Class C standard differ from those of the Class B standard, the provisions of the Class C standard take precedence. Relevant safety function requirements can be found in IEC 62061 and ISO 13849-1.
Compliance and certification considerations
Manufacturers should establish complete technical documentation when applying this standard, including: risk assessment report, basis for selection of shutdown category, equipment selection instructions, installation layout drawings, test verification records, etc. For mechanical equipment exported to the EU, it is recommended to conduct a conformity assessment through an EU-authorized notified body to obtain the CE mark.
It is particularly important to note that the emergency stop function cannot replace other protective measures or safety functions, but should be designed as a supplementary protection measure. The emergency stop function shall not affect the effectiveness of protective devices or other safety function devices.