EN ISO 13850 Sets Key Safety Standards for Emergency Stop Systems

Imagine this scenario: machines roar on the production line as workers operate them under tight schedules. Suddenly, an accident occurs. An operator swiftly presses a red button, bringing all machinery to an immediate halt and preventing potential disaster. This red button represents what we now examine—the emergency stop device—a crucial component in mechanical safety governed by the EN ISO 13850 standard.

The Machinery Directive 2006/42/EC explicitly requires that equipment must incorporate one or more emergency stop devices to prevent actual or imminent hazards. The primary function of these systems is to halt dangerous machine operations as quickly as possible without introducing additional risks.

However, not all machinery requires emergency stop devices. Exceptions apply when such devices cannot reduce stopping time or when specific risk mitigation measures are impractical. Portable handheld or hand-guided machines typically don't require emergency stops either.

It's crucial to understand that emergency stops don't provide direct protection and therefore shouldn't be considered risk reduction measures. They serve as supplementary safeguards to other protective measures like safety guards and protective devices—acting as the last line of defense rather than the primary one.

According to regulatory requirements, proper emergency stop devices must meet these critical criteria:

• Clearly identifiable and easily operable: Controls must be immediately recognizable, highly visible, and readily accessible. This typically involves using high-visibility colors (like red) and ergonomic designs for rapid activation during emergencies.
• Rapid cessation without secondary risks: The system must stop hazardous processes at maximum speed while preventing additional dangers. This demands both quick response times and reliable braking mechanisms to ensure minimal stopping duration.
• Safety action initiation: When necessary, the device should trigger or permit activation of complementary safety measures. Some scenarios may require simultaneous engagement of additional safety systems to protect personnel and equipment.

As a cornerstone standard in mechanical safety, EN ISO 13850 provides comprehensive guidelines for designing and implementing emergency stop functionality. The standard addresses device types, performance requirements, placement, operation methods, and maintenance protocols.

The standard defines multiple emergency stop configurations suited for different applications:

• Push-button devices: The most common type, typically installed on control panels or within easy operator reach. These feature distinctive red mushroom-head buttons for quick identification.
• Cable-pull devices: Ideal for applications requiring emergency stop capability along extended areas, such as conveyor systems. Activation occurs by pulling the cable.
• Foot-operated devices: Designed for situations where operators need both hands for machine control. Activation occurs through pedal depression.

EN ISO 13850 establishes rigorous performance criteria including response time, reliability, and interference resistance to ensure dependable emergency operation:

• Response time: Must be sufficiently brief to prevent hazards, with specific requirements varying by machine type and risk level.
• Reliability: Requires high-quality components, robust design, and regular maintenance/testing to guarantee operational readiness.
• Interference resistance: Must maintain functionality despite electromagnetic interference or vibration through proper shielding and design.

Strategic placement is critical for effective emergency stop operation:

• Accessibility: Positioned within easy operator reach, typically on control panels or near workstations.
• Visibility: Clearly marked with high-contrast colors and signage, unobstructed by other equipment.
• Accident prevention: Located to minimize accidental activation from routine operations or collisions.

The standard specifies operational requirements to ensure proper usage:

• Intuitive operation: Simple activation methods requiring minimal training.
• Clear instructions: Visual or textual guidance for proper use.
• Persistent deactivation: Machines must remain stopped until manual reset prevents automatic restart during hazardous conditions.

Regular upkeep ensures ongoing reliability:

• Scheduled inspections: Regular checks of physical condition, connections, and functionality.
• Performance testing: Periodic verification of response times and operational reliability.
• Preventive maintenance: Component replacement and lubrication per manufacturer specifications.

The November 2015 revision introduced significant enhancements to improve safety and reliability in modern industrial environments, with detailed specifications in updated standard sections.

Emergency stop functionality remains a fundamental aspect of mechanical safety, with EN ISO 13850 providing essential guidance for effective implementation. Proper adherence to these standards significantly reduces equipment hazards while protecting personnel and assets. In mechanical safety planning, emergency stop systems warrant careful consideration as integral components of comprehensive safety strategies.