FCP-500 Conventional Flush-mount Smoke Detector

The art of invisible smoke detection

The FCP-500 series is the industry's only flush-mounting ceiling detector. Using revolutionary, patented Bosch technology, the detector appears as a smooth plastic plate, flush with the ceiling surface! There are optional color rings to help further disguise its presence.


Features with benefits

  • Detector mounts nearly flush in ceiling - does not intrude upon or detract from interior design in specialized facilities
  • Unique dual virtual chamber design - minimizes false alarms and improves detection, especially in dusty, dirty environments
  • Flat face plate and lens - easy to clean and maintain
  • Custom color face plates - 16 optional colored trim ring kits let the FCP-500 blend in with every ceiling
  • Optional carbon monoxide sensor - virtually eliminates false alarms with automatic sensitivity adjustment
  • Anti-masking sensor - signals the panel if the detector is covered up
  • Contamination sensor - monitors dust build up and signals the panel if the lens is obstructed
  • Drift compensation - automatically adjusts for dust and dirt build up on the lens
  • Compatible with almost all four-wire capable fire alarm control panels - ideal for renovation work as well as new construction
  • Easy installation and mounting - modular construction makes it simple to install



NEW: Dual Ray Technology for detection of smallest particles

Detectors equipped with Dual Ray Technology stand for ultimate precision:

  • With the detection of smallest smoke particles (test fire TF1) an even more reliable and early fire detection is achieved
  • Dual Ray Technology takes advantage of the Mie principle to determine smoke density and particle size, comparing the intensity of scattered light from the differing wavelengths of two LED sources, one infrared and one blue
  • As a result the reduction of false alarms by more reliable differentiation between fire and disturbances is achieved
  • Dual Ray Technology is integrated in the new dual-optical variants (FAP-DO 420, FAP-DOT 420, FAP-DOTC 420)

A cost-effective approach – The FAP-DO 420

  • Detects test fire TF1 with a dual-optical sensor
  • This results in a cost-advantage over some competitors which require a multisensor detector (optical and thermal or dual-optical and thermal sensors) to provide detection of TF1

ISP (Intelligent Signal Processing) Technology

All 420 Series detectors use Bosch's own Intelligent Signal Processing (ISP) Technology, which achieves the highest level of intelligent fire detection.

Mode of operation for ISP

  • Sensor signals are analyzed and linked together, and processed through the ISP technology, using a unique algorithm
  • The algorithm itself is based on rules derived from the experience of 5,000 fire patterns
  • If the combined signals correspond to a specific fire-pattern, an alarm is triggered


  • More precise analysis of sensor signals
  • Best-in-class differentiation between real fires and disturbances



  • EMC stability of 50 V/m from 1 MHz to 3 GHz for use in areas with a WLAN
  • Drift compensation in optical and gas measurements for optimal detection at all times
  • Day/night mode switching for individual sensor configuration
  • Two integrated isolators for maintaining loop functionality and operability in the event of wire interrupts or short circuits
  • Colored rings on each detector identify the sensor variants
  • Bosch's LSN bus Technology for fire and intrusion systems can be used to connect the 420 Series, along with all the other fire peripherals, to a fire panel


  • The 420 Series detectors are equipped with different kinds of sensors to detect every kind of fire (Single optical sensor, dual-optical sensor, Thermal sensor and Chemical (CO gas) sensor)
  • Equipped with Dual Ray Technology and Intelligent Signal Processing (ISP), the Automatic Fire Detector 420 Series detects fires faster than ever and minimizes false alarms, for the highest levels of protection and reliability in every environment
  • Fewer False Alarm: Specific parameters, separate from the fire patterns, increase the detector's precision. There are pre-programmed settings, for example, for use in dusty environments, or when smokers are present. These parameters make the detector even better at distinguishing fires from other disturbances over a broader range of operating conditions
  • Earlier Detection: In addition, the multisensor algorithm parameters are adapted to different application types, to further optimize early fire detection and false alarm immunity. They also enhance immunity from ambient influences such as dust, humidity, and temperature variation. This ensures best-in-class differentiation between real fires and disturbances
  • The Automatic Fire Detector 420 Series is a secure investment that delivers maximum value. Built with components that meet the highest Bosch standards for quality, every 420 Series detector is remarkably reliable and has proven longevity
  • Every model meets the rigorous requirements of the EN54 standard
  • The FAP-DO 420 detector can also be used to replace ionization detectors, which use radioactive material that requires special handling and is extremely difficult to recycle
  • 420 Series supports programmable parameters so it's easy to create a system fully tailored to individual needs




Accurate detection, everywhere you need it

Different substances burn differently, and no two fires are exactly alike. Smoldering paper in a waste basket, for example, generates smoke but very little heat, while an industrial fire involving ethanol gives off no smoke yet has a strong heat flow.

The 420 Series takes all these possibilities into account, meeting EN54 fire-type requirements and offering options that cover every fire criteria, from type of material and heat flow to airstream, smoke emission, and aerosol characteristics.


The new dual-optical models, with their high precision Dual Ray Technology, deliver an added level of reliability and provide early detection in even the most challenging environments, including nightclubs, parking garages, and computer rooms.