The Kidde KF21R Sentry Optical Smoke Alarm is a high-performance mains-powered smoke detector designed to provide dependable fire detection throughout residential properties. Featuring an advanced optical sensor, the KF21R is ideal for detecting slow, smouldering fires commonly caused by upholstered furniture, electrical faults and cigarettes.
Equipped with a sealed rechargeable lithium battery back-up, this alarm continues to operate during mains power failures without the need for battery replacement. The KF21R can also be interconnected with up to 23 compatible Kidde FIREX smoke, heat and carbon monoxide alarms, ensuring all alarms sound simultaneously when danger is detected.
Designed for straightforward installation, the alarm features Kidde’s Quick-Fit Slide-On Base for fast, tool-free fitting. The integrated cable management system helps maintain tidy wiring, while the 150mm flared base provides a neat finish during retrofit projects.
Key Features
Mains-powered optical smoke alarm with sealed rechargeable lithium battery back-up
Interconnects with up to 23 compatible Kidde FIREX alarms
Optical sensor technology for detecting slow, smouldering fires
Quick-Fit Slide-On Base for fast, tool-free installation
150mm flared base plate for neat retrofitting
Integrated cable management for secure and tidy wiring
Alarm memory identifies the activated unit within the network
Combined Test/Hush button for easy testing and temporary silencing
Automatic reset after alarm activation
Tamper-resistant locking mechanism for added security
Suitable for lofts, hallways, bedrooms and living areas
Fully compatible with Kidde FIREX smoke, heat and CO alarms
10-year manufacturer warranty
Ideal Applications
The Kidde KF21R optical smoke alarm is recommended for installation in:
Hallways and circulation routes
Bedrooms
Living rooms
Attics and loft spaces
Residential Grade D1 fire alarm systems
Optical smoke alarms are particularly effective at detecting slow-burning fires and are ideal for escape routes and living spaces.
Technical Specifications
Model: KF21R
Power Supply: 230V mains with sealed rechargeable lithium battery back-up
Sensor Type: Optical with dust compensation and bug screen
Alarm Volume: Minimum 85dB at 3 metres
Alarm Frequency: 3.2 kHz typical
Interconnectivity: Up to 23 compatible alarms
Alarm Grade: D1
Approvals: BSI certified to BS EN14604:2005
Dimensions: 150mm x 150mm x 53mm
Weight: 260g including battery
Operating Temperature: -10°C to +40°C
Humidity Range: Up to 93% RH non-condensing
Warranty: 10 Years
Compliance & Installation
The Kidde KF21R complies with UK Building Regulations and BS 5839 Part 6 standards for Grade D domestic fire alarm systems. Installation should be completed by a qualified electrician. For kitchen installations, a dedicated Kidde FIREX heat alarm is recommended instead of a smoke alarm.
The Kidde KF21R Sentry Optical Smoke Alarm is a high-performance mains-powered smoke detector designed to provide dependable fire detection throughout residential properties. Featuring an advanced optical sensor, the KF21R is ideal for detecting slow, smouldering fires commonly caused by upholstered furniture, electrical faults and cigarettes.
Equipped with a sealed rechargeable lithium battery back-up, this alarm continues to operate during mains power failures without the need for battery replacement. The KF21R can also be interconnected with up to 23 compatible Kidde FIREX smoke, heat and carbon monoxide alarms, ensuring all alarms sound simultaneously when danger is detected.
Designed for straightforward installation, the alarm features Kidde’s Quick-Fit Slide-On Base for fast, tool-free fitting. The integrated cable management system helps maintain tidy wiring, while the 150mm flared base provides a neat finish during retrofit projects.
Key Features
Mains-powered optical smoke alarm with sealed rechargeable lithium battery back-up
Interconnects with up to 23 compatible Kidde FIREX alarms
Optical sensor technology for detecting slow, smouldering fires
Quick-Fit Slide-On Base for fast, tool-free installation
150mm flared base plate for neat retrofitting
Integrated cable management for secure and tidy wiring
Alarm memory identifies the activated unit within the network
Combined Test/Hush button for easy testing and temporary silencing
Automatic reset after alarm activation
Tamper-resistant locking mechanism for added security
Suitable for lofts, hallways, bedrooms and living areas
Fully compatible with Kidde FIREX smoke, heat and CO alarms
10-year manufacturer warranty
Ideal Applications
The Kidde KF21R optical smoke alarm is recommended for installation in:
Hallways and circulation routes
Bedrooms
Living rooms
Attics and loft spaces
Residential Grade D1 fire alarm systems
Optical smoke alarms are particularly effective at detecting slow-burning fires and are ideal for escape routes and living spaces.
Technical Specifications
Model: KF21R
Power Supply: 230V mains with sealed rechargeable lithium battery back-up
Sensor Type: Optical with dust compensation and bug screen
Alarm Volume: Minimum 85dB at 3 metres
Alarm Frequency: 3.2 kHz typical
Interconnectivity: Up to 23 compatible alarms
Alarm Grade: D1
Approvals: BSI certified to BS EN14604:2005
Dimensions: 150mm x 150mm x 53mm
Weight: 260g including battery
Operating Temperature: -10°C to +40°C
Humidity Range: Up to 93% RH non-condensing
Warranty: 10 Years
Compliance & Installation
The Kidde KF21R complies with UK Building Regulations and BS 5839 Part 6 standards for Grade D domestic fire alarm systems. Installation should be completed by a qualified electrician. For kitchen installations, a dedicated Kidde FIREX heat alarm is recommended instead of a smoke alarm.
