Type C Entrapment Protection involves which of the following?

• A. Monitored non-contact sensors
• B. Inherent force limiting or adjustable clutch, permitted by UL 325 for swing gates and barrier arms
• C. Contact edge sensors
• D. Continuous pressure devices

Answer: (B)

Type C entrapment protection means relying on built-in, mechanical safety rather than external sensors. It uses inherent force limiting or an adjustable clutch integrated into the operator, so the gate cannot exert dangerous force and can slip or disengage if an obstruction is met. UL 325 permits this approach for swing gates and barrier arms, making the mechanism itself safe by limiting the applied force. This is different from monitored non-contact sensors, which rely on sensing an obstacle (Type A), or from contact edge sensors, which detect physical contact with a edge or bumper, and from continuous pressure devices that require constant pressure to move. The inherent force-limiting approach reduces entrapment risk even if sensing fails, which is why it’s categorized as Type C.