Request-to-Exit (REX) Devices in Access Control

Key Considerations for Decision Makers

Access control systems are essential for ensuring the safety and security of modern facilities. A critical component of these systems is the Request-to-Exit (REX) device, which facilitates secure and authorized egress from restricted areas. This article explores how REX devices interact with fail-safe and fail-secure systems, outlines key installation and maintenance considerations, and highlights relevant industry standards for compliance. Decision-makers will gain a comprehensive understanding of REX functionality to make informed choices for their facilities.

Understanding Request-to-Exit (REX) Devices

REX devices are designed to detect an individual’s intent to exit and signal the access control system to release a door lock temporarily. These devices are commonly used in:

• Commercial Buildings: Regulating exit points for employees and visitors.
• High-Security Facilities: Managing egress from sensitive areas such as data centers or laboratories.
• Healthcare Facilities: Allowing quick and secure exits in emergencies.

How REX Devices Work

REX devices typically utilize motion sensors, touch bars, or manual switches to detect exit requests. Upon activation, the device sends a signal to the access control system, which releases the locking mechanism and allows the door to open. Key parameters include:

1. Detection Area and Distance Curtain: REX devices define a detection zone (often 3–15 feet from the door) to capture motion accurately without false triggers.
2. Capture and Release Timing: Configurable timers ensure smooth egress while maintaining security.
3. System Integration: REX devices often interface with fire alarms, door position switches, and security cameras for enhanced functionality.

REX Devices in Fail-Safe and Fail-Secure Systems

Fail-Safe Systems

• Definition: Doors unlock automatically during power failures, prioritizing safety.
• REX Interaction: Activates door release during normal operation. Secondary during power loss, as the door unlocks automatically.
• Use Cases: Public spaces and emergency exits where occupant safety is paramount.
• Considerations: May compromise security during intentional power disruptions.

Fail-Secure Systems

• Definition: Doors remain locked during power failures, prioritizing security.
• REX Interaction: Requires backup power for REX devices to operate during outages. Often integrates with fire alarms for override functionality.
• Use Cases: High-security areas such as server rooms or restricted zones.
• Considerations: Ensures security but must comply with egress requirements through integration with emergency systems.

Comparison Chart

Installation and Maintenance Guidelines

1. Mounting Height and Position: Install REX devices 7–10 feet above the floor to balance accessibility and tamper resistance. Position to avoid false triggers from environmental factors (e.g., sunlight or airflow).
2. Distance from Door: Configure detection zones 3–15 feet from the door, ensuring compliance with fire and building codes.
3. Security Measures: Use tamper-resistant screws and robust housing to prevent tampering. Integrate with door position switches and alarms for enhanced monitoring.
4. Routine Maintenance: Conduct regular functionality tests-I know good luck getting them to do that right, including environmental stress tests (e.g., smoke tests) to assess reliability. Verify integration with fire alarms and backup power systems.

Compliance with Standards

Adhering to industry standards ensures that REX devices are safe, functional, and compliant with regulations:

• ANSI/TIA-569-E: Specifies environmental guidelines for REX installation in telecommunications pathways and spaces. Ensures stable operating environments for electronic devices
• NFPA Codes: NFPA 101: Mandates free egress without special knowledge or effort. NFPA 72: Requires that electronically locked doors unlock during fire alarms or power loss.
• NEC (National Electrical Code): Ensures safe electrical connections and backup power integration for REX devices.

1. Article 110.26(C)(3) – Personnel Doors: Scope: This section addresses requirements for personnel doors serving electrical equipment rooms containing equipment rated 800 amperes or more. Doors intended for entrance to and egress from the working space must open in the direction of egress. Doors must be equipped with listed panic hardware or listed fire exit hardware. While REX devices are not specifically mentioned, ensuring that egress doors in electrical rooms operate effectively during emergencies is crucial. Integrating REX devices with panic hardware can facilitate quick and safe exits.
2. Article 300.25 – Exit Enclosures (Stair Towers): This section prohibits installing conduits in separated exit enclosures or stair towers unless the conduits are associated with the exit enclosure. When installing REX devices in or near exit enclosures, ensure that any associated wiring complies with this requirement to maintain the integrity of the exit pathway.
3. Article 110.26(C)(2) – Large Equipment: his section mandates sufficient entry to and egress from the working space required for large equipment, defined as equipment with overcurrent devices, switching devices, or control devices rated 1,200 amperes or more and over 6 feet wide. There must be at least one entrance to and egress from the required working space not less than 24 inches wide and 6.5 feet high at each end of the working space. While not directly mentioning REX devices, ensuring clear and accessible egress paths in areas with large electrical equipment is vital. Incorporating REX devices can enhance safety by providing efficient exit mechanisms.
4. NESC (National Electrical Safety Code): Addresses safety in communication utility installations, relevant for systems connected to REX devices.

Considerations for Business Owners and Decision-Makers

1. Balancing Safety and Security: Evaluate the environment and usage of each access point to determine whether fail-safe or fail-secure configurations are more appropriate. Consider high-traffic areas versus restricted zones when choosing the system type.
2. Liability and Compliance: Document all installation and maintenance activities. Use liability forms to address vulnerabilities identified during installation or testing.
3. Investing in Integration: Combine REX devices with surveillance systems, fire alarms, and door position sensors to create a holistic access control solution.
4. Long-Term Planning: Budget for routine testing and system upgrades to maintain compliance with evolving standards.

Conclusion

Request-to-Exit devices are essential for secure and efficient access control systems, providing a balance between safety and security. Proper installation, configuration, and adherence to standards such as ANSI/TIA, NFPA, NEC, and NESC ensure these devices perform reliably in any scenario. Business owners and decision-makers must work closely with security professionals to tailor REX systems to their specific needs, ensuring both compliance and peace of mind.

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