Bosch LSN Improved Version Automatic Fire Detectors

Product Description

The Series 520 fire detectors combine the functionalities of LSNi (LSN improved) technology with the aesthetic advantages of flush-mounting and the option to choose the preferred color. These detectors can be connected to any LSNi fire alarm control panel and also to all LSN fire alarm control panels in standard mode.

Detectors with a matching sealing ring are available in white and transparent versions with colored inserts. The supplied inserts allow for optimal adaptation of the device to different ceiling colors.

The absence of an optical chamber and the smooth, easy-to-clean surface make these detectors suitable for applications in areas with high dust levels. The flush-mount design allows for their use in areas where protrusions must be avoided.

Thanks to the geometric arrangement of two separate optical sensor systems, the detectors are insensitive to interference, such as from insects. The volume of scattered light examined by the sensors is located a few centimeters below the ceiling.

The contamination level is continuously measured. Contamination of the detector surface triggers active threshold adjustment (drift compensation) and sends a maintenance signal to the control panel in case of high contamination.

The detector is available as an optical fire detector or as a multi-sensor detector with an additional gas sensor. The combination of the optical detector and the gas sensor allows for signal analysis using modern signal processing methods, resulting in high immunity against false alarms and broader application possibilities in environments not suitable for simple optical smoke detectors.

Integrated rotary switches allow for automatic or manual address allocation. The FAP-520 detectors can be directly connected to the LSN (Local Security Network).

Accessories

The Series 520 detectors are typically flush-mounted in suspended ceilings. The detector and base are installed in a robust rear housing for ceiling mounting. Additionally, an integrated housing can be used for mounting in concrete ceilings.

For special applications where flush-mounting in suspended ceilings is not possible, a surface-mount rear housing is available. This housing, with a seal for humid environments, also allows the detector to be used in environments with high humidity levels. The base is available with a relay variant for special applications, such as controlling emergency doors in accordance with DIBt regulations. All bases feature an integrated cable clamp. Connection terminals are easily accessible. Cables with a cross-sectional area of up to 3.3 mm² can be used.

An innovative concept for the detector module block, based on a double push-in/push-out principle, ensures quick and easy detector insertion and removal. A special accessory is available for detector testing and replacement.

Overview of Series 520 Detectors and Accessories:

• LSNi Detectors:
• FAP-O 520: LSNi optical fire detector, white
• FAP-O 520-P: LSNi optical fire detector, transparent with colored inserts
• FAP-OC 520: LSNi multi-sensor fire detector, optical/chemical, white
• FAP-OC 520-P: LSNi multi-sensor fire detector, optical/chemical, transparent with colored inserts
• Sealing Rings:
• FAA-500-TR-W: White sealing ring for Series 500 and 520 detectors
• FAA-500-TR-P: Transparent sealing ring with colored inserts for Series 500 and 520 detectors
• Detector Bases:
• FAA-500: LSN detector base
• FAA-500-R: LSN detector base with relay
• Mounting Boxes:
• FAA-500-BB: Rear housing for ceiling mounting
• FAA-500-CB: Integrated housing for concrete ceilings
• FAA-500-SB-H: Rear housing for surface mounting with seal for humid environments
• Service Accessories:
• FAA-500-RTL: Replacement device for Series 500 and 520 detectors
• FAA-500-TTL: Test adapter with magnet for Series 500 and 520 detectors

System Description

All Series 520 detectors are equipped with two optical sensors and one contamination sensor. The FAP-OC 520 multi-sensor detector includes a gas sensor as an additional detection channel. The detector's response sensitivity can be programmed using the LSN network programming software. All sensor signals are continuously analyzed by the internal processor and interact with each other.

Through the connection of optical sensors and the chemical sensor, the OC detector can also be used in locations with small amounts of smoke, vapor, or dust. The alarm is automatically activated only if the combination of signals matches the characteristic pattern selected during configuration.

Detector Configuration

The detector features a front view with sensors and a side view of the detector cover. Key components include:

• 1. Optical Sensor: Detects smoke particles.
• 2. Receiver (Photodiodes): Converts received light into an electrical signal.
• 3. Transmitter (LED): Emits light for the optical sensor.
• 4. CO Sensor (OC variants only): Detects carbon monoxide (CO), hydrogen (H), and nitrogen monoxide (NO).
• 5. Two-color LED: Indicates status (red for alarm, green for test/fault).
• 6. Contamination Sensor: Measures the contamination level of the detector surface.
• 7. Measurement Area: The area where smoke is detected.

Functional Description of Sensor Technology

Optical Sensor (Smoke Detector)

The optical sensor operates based on the scattered light principle. LEDs transmit light into the measurement area. When smoke particles are present, they scatter the light, which is then detected by photodiodes, converting the light quantity into a proportional electrical signal. Filters are used to eliminate interference from sunlight and artificial light sources.

Chemical Sensor (CO Gas Sensor)

The gas sensor detects carbon monoxide (CO), hydrogen (H), and nitrogen monoxide (NO) produced during a fire. It measures CO concentration proportionally to the generated current. The CO sensor is monitored for internal capacity. If the capacity is outside the allowed range, a fault signal is generated, and the detector functions solely as an optical smoke detector.

Contamination Sensor

This sensor continuously measures and evaluates the contamination level of the detector's surface. Three contamination levels can be displayed during service. This allows for active threshold adjustment and maintenance signaling.

LED Operation

The two-color LED indicates the detector's operating status and alarm condition. During operation, sensors are continuously monitored, and sensitivity is automatically adjusted. In case of significant contamination, a message is sent to the fire alarm control panel. During an alarm, the LED flashes red. The detector returns to standby mode when the alarm is reset and the cause is cleared.

LED Status:

• Standby: LED is off.
• Alarm: LED flashes red.
• Fault: LED is off.
• Test Mode: LED flashes green once per second.

Installation Instructions

General Notes

Warning! The Series 520 detectors are approved for indoor use only. They must be installed exclusively on the supplied FAA-500 bases. The detector base must be installed in either an FAA-500-BB rear housing for ceiling mounting or an FAA-500-SB-H rear housing for surface mounting.

During the design phase, local regulations and guidelines must be observed. The FAP-OC 520 and FAP-O 520 units comply with optical detector guidelines (EN 54 and VDS 2095).

Maintain a hemispherical space (1) with a radius of 50 cm below the detector (2), ensuring no people, large animals, plants, open doors, or other objects obstruct this area. No part of the detector should be covered.

Detectors must be installed in locations that are difficult to reach. The recommended minimum installation height is 2.70 m. Series 520 detectors cannot be installed in environments with high-intensity infrared light (e.g., interpreter systems).

Install detectors away from direct sunlight and maintain a minimum distance of 50 cm from lamps. Detectors should not be mounted within the light cone of lamps.

Bases are equipped with a spring for mounting on concrete and wooden ceilings (identified by a blue marking). For suspended ceilings, an additional softer spring (yellow marking) can be used. In this case, the detector must not be subjected to strong vibrations (> 350 m/s), as electrical shock resistance according to EN 54-7 may not be guaranteed.

Maximum permissible air velocity is 20 m/sec.

LSNi Network Topologies

In an LSNi (LSN improved) local security network, detectors can be configured in various topologies: loop, open line, T-tap, or mixed structures. Square structures are not supported.

The LSNi network supports T-tap systems on open lines or loops and any number of nodes, branches per node, and branching elements, provided the total does not exceed 254 elements. Connections can be made at any point on the LSN line. Detailed information on topologies is available in the control panel system manual.

Warning! For planning, consider the total current consumption and line resistance to ensure a minimum operating voltage of 15 VDC for each detector. Use Safety Systems Designer (SSD) for detailed calculations and planning. If an LSN classic device is on a loop or open line, only loops or open lines can be used; T-tap systems are not possible.

Installation

Rear Housing for Ceiling Mounting (FAA-500-BB)

The rear housing is made of white polypropylene and features four cable glands with rubber seals suitable for cables up to 1.4 cm in diameter. Approximately 30 cm of cable length can be accommodated above the housing.

Warning! The maximum suspended ceiling thickness should not exceed 32 mm. A free space of at least 11 cm must be left above the suspended ceiling. A circular hole with a diameter of 130 mm (tolerance -1 mm to +5 mm) must be drilled in the suspended ceiling.

Installation Steps:

1. Insert the cable into one of the provided cable glands (3). A cable tie around the protective sheath prevents accidental pulling.
2. Insert the rear housing into the suspended ceiling from below.
3. Align the triangular symbols (M) on the outer edge of each rear housing so that the oblong windows in the center of the detectors form a straight line for a harmonious appearance.
4. Tighten the brackets (1).

Attention! For standard suspended ceilings, it is recommended not to use an electric screwdriver.

Detector Base / Detector Base with Relay

The base housings are made of white polycarbonate. Screw terminals (for cables with cross-sectional areas from 0.3 mm² to 3.3 mm²) ensure secure electrical connection with tight contacts during detector installation. The bases are equipped with three supports for cable ties to secure the base during wiring.

Warning! If relay bases are used, remote indicators cannot be connected.

Base Connection: Wire the LSN base according to the indications on the outer ring (3).

Figure 3.5: Top view of the base

Figure 3.6: Base wiring

Wiring Table:

* Terminals for loop-through of power for other LSN devices.
** For switching capacity, see Detector Base, page 31.

The base is secured to the rear housing for ceiling mounting with four screws. It can be rotated in the elongated holes by an angle of 20° for precise alignment.

Figure 3.7: Positioning the base in the rear housing for ceiling mounting

Installation Steps:

1. Position the base in the rear housing for ceiling mounting so that the symbol on the rear housing (1) aligns with the single groove on the base (2).
2. Rotate the base until the mounting screws approximately align with the center of the elongated holes (3).
3. Adjust the bases around this point until they are aligned.
4. Tighten the four screws.

Addressing

Detector addresses are assigned using the three rotary switches on the rear of the device. Use a flat-head screwdriver to set each switch. Each switch emits a click when moved. All detectors are factory-set to 0 0 0.

Figure 3.8: Rotary switches

Addressing Table:

When connecting detectors to LSN BZ 500 LSN, UEZ 2000 LSN, or UGM 2020 fire detection control panels, all detectors must be assigned the address CL 0 0. When connecting detectors to the modular fire alarm control panel, address allocation can be automatic or manual.

For manual allocation, the address of all detectors installed in a loop, open line, or T-tap must be between 001 and 254. Addresses between 255 and 299 are not permitted and will generate a fault message on the control panel.

If addresses are assigned automatically by the fire detection control panel, all detectors must have the address 000.

Addressing Scenarios:

Detector and Sealing Ring

Detector and Sealing Ring Insertion

Warning! Detectors with a C sensor are packed in a wear-resistant PE-ALU laminated film. Carefully cut the film to remove it. Do not remove the protective film before positioning the detector.

Colored Ring Insertion

Warning! Do not alter the detector's front plates in any way. The contamination sensor is calibrated for each individual detector and its respective front plate. Any alteration of the front plates may lead to incorrect contamination readings.

Steps:

1. The detector's front panel (1) is secured with a small snap hook (2) located on the lateral triple groove. Insert the opening tool (3) into the slot above the snap hook (4); lower the tool with your thumb and rotate the front part counter-clockwise.
2. The supplied colored rings (5) are attached to the front panel (1), and the detector is then attached to the ceiling. The front panel is designed for a single insertion position.
3. Rotate the front panel clockwise until it clicks into place. The sensor window must not be obstructed.
4. Insert the desired colored ring into the FAA-500-TR-P sealing ring (6).

Detector and Sealing Ring Insertion

Warning! The FAA-500-RTL detector replacement device is recommended for inserting and removing detectors.

1. Push the sealing ring onto the base until it clicks into place (7).
2. Remove the protective film from the detector surface. During initial configuration, the system detects the absence of the protective film on the detector and signals any anomalies with a malfunction message.
3. Insert the detector and press gently upwards. The device locks with a "click and lock" mechanism. The grooves ensure that the detector is inserted onto the base only in the correct position.
4. For particularly high installation heights, the two visible contact sides (8) are located on the same side as the single groove (9).

Integrated Housing for Concrete Ceilings (FAA-500-CB)

The FAA-500-CB integrated housing is used for installing the detector in concrete ceilings and simplifies conduit connections. The housing is placed on the concrete block, tightened, and secured to prevent oscillation. Ensure nails are fully within the polystyrene during fastening to avoid interference when cutting the polystyrene. Openings for pipes or cables between the integrated housing and the wall can be made with a universal cutting tool. After removing panels, open the front part (1) with a jigsaw or a hole saw. Then, insert the FAA-500-BB rear housing for ceiling mounting into the opening of the integrated housing to accommodate the base and detector.

Rear Housing for Surface Mounting

The FAA-500-SB-H rear housing allows for surface or flush conduit installation and includes an additional seal for humid environments. Use the side openings for surface-level cable conduits and the bottom openings for flush conduits. For 13.5 mm cable glands, the maximum cable diameter is 12 mm.

Mounting is done through the elongated slots or via the four mounting holes for direct installation into 10.16 cm electrical boxes or single switch boxes (for the USA). The base is installed inside the rear housing using four fixing points.

Figure 3.12: Fixing points for mounting

Remote Indicator

A remote indicator is necessary if the detector is not directly visible or is installed in suspended ceilings or floor voids. Remote indicators should be installed in corridors or access passages to the affected sections or rooms of the building.

Warning! If unshielded cables are used for the remote indicator connection, the maximum cable length is 3 m. There is no limitation if shielded cables are used.

Installation of Remote Indicator FAA-420-RI:

Warning! Malfunction and Damage: If the connected detector's maximum current consumption exceeds 20 mA, it may cause malfunction or damage to the remote indicator. Ensure the maximum current consumption of 20 mA is not exceeded. Use Bosch automatic detectors with a zone type that includes an internal resistance limiting current consumption.

Wiring the remote indicator as shown.

Operating Modes and Alarm Conditions:

Operate only in modes 1 and 3 when connected to LSN detectors.

Installation Steps:

1. Position the cover onto the base so that the two hooks are inserted into the slots.
2. Gently press onto the base until the snap hook engages.

Wiring the remote indicator as shown.

1. Position the cover onto the base so that the two hooks are inserted into the slots.
2. Gently press onto the base until the snap hook engages.

Programming

LSN detectors can be programmed according to individual requirements. Programming is done using the programming software with a PC or laptop connected to the fire detection control panel.

The appropriate response sensitivity of the multi-sensor detector is programmed by specifying the installation location (e.g., computer room, office, large kitchen). The choice of deployment location determines the optimal characteristic diagram for evaluating fire and disturbance variables.

If a low sensitivity is set for the optical sensor based on the installation location, the alarm is activated only when high levels of smoke and CO are detected simultaneously, such as in the case of a flashover fire without flames.

Programming the multi-sensor detector and associating all detectors using algorithms significantly increases the reliability of fire detection and reduces the possibility of false alarms.

Installation Locations for Multi-Sensor Detector (FAP-OC 520) Selectable via Programming Software:

For the FAP-O 520 optical detector, the optical sensor sensitivity can be set to three levels. The detector's optical sensor can be programmed according to environmental conditions. For fire detection, the time factor of the fire characteristics, which differs significantly from the time factor of disturbance variables, is also evaluated.

Recommended Installation Locations and Settings for Optical Fire Detector (FAP-O 520) Selectable via Programming Software:

Warning! For functional testing of FAP-O 520 and FAP-OC 520 detectors, the detector must be set to test mode. Testing can be performed via the fire alarm control panel or the detector's reed switch using a magnet (see Maintenance and Service, page 24).

Maintenance and Service

Warning! Series 520 detectors must not be removed from their bases for routine maintenance. If a detector needs to be replaced due to damage or design changes, this must be performed by qualified personnel. The system must be offline during device replacement, and alternative emergency evacuation measures must be in place.

In Germany, maintenance and verification work on safety systems is governed by DIN VDE 0833 directives, which specify maintenance intervals. Maintenance and verification work must be performed regularly by qualified personnel.

Bosch recommends an annual functional and visual inspection. Remote maintenance is permitted for certain procedures, including activating the detector with a test criterion. Series FAP-520 detectors meet the requirements for remote maintenance. Remote functional testing is permitted only if performed in accordance with the manufacturer's approved test procedure.

Test Phases:

FAP-OC 520

Warning! The lifespan of the gas sensor determines the deactivation of the C sensors in the FAP-OC 520 detector after approximately 5 years of operation. The detector will continue to function as an O detector. A fault signal will be displayed on the fire alarm control panel. Immediately replace the detector to ensure maximum reliability of the OC detector.

Warning! Cleaning intervals depend on environmental conditions. The detector can be cleaned with a soft cloth and a plastic cleaner. Cleaning must only be performed in test mode.

Refer to: Verification Procedure for FAP-O 520 Detector, page 27

Notes for Service

Warning! The serial number, contamination level, operating hours, and current analog values of all configured detectors can be read from the fire alarm control panel's display.

Contamination Level: Contamination level is indicated as a percentage:

Operating Hours: Displays operating time in hours from first use.

Current Measurement Values:

Analog value of scattered light smoke sensor:

CO Value: Current measurement value of the CO sensor (FAP-OC 520 model only). Maximum measurement value is 1023.

General Notes for Detector Testing

The FAP-OC 520 detector has an additional CO gas detection sensor for fires, offering better response and greater stability against unwanted alarms in critical environmental conditions. For fire detection, FAP-520 detectors utilize the time factor of fire characteristics, which differs significantly from the time factor of disturbance variables. Therefore, for functional testing, the detector must be set to test mode. Test mode can be activated in two ways:

Warning! Detectors programmed for two-detector dependency must be tested as described in the first alternative (test mode).

Required for Detector Testing:

• Test device for optical fire detector and
• Test adapter FAA-500-TTL with magnet.

For OC detectors, a CO test gas is also required.

Verification Procedure for FAP-OC 520 Detector

Option 1

Use the remote functional test to test detectors. Warning! Remote functional testing is only permitted if performed in accordance with the manufacturer's approved test procedure.

Option 2

1. On the central unit, switch the detection zone to test mode. This automatically sets the detector to test mode and prepares it for testing. Only in test mode do the individual detector sensors activate their corresponding test device. For an alarm signal, all sensors must activate simultaneously. The C sensor is activated using CO test spray; the O sensors are covered. No O test gas is required.
2. Place the test device under the detector so that the test cup is level with the sealing ring and seals tightly. Check that the cup is not tilted, as this could lift the detector and cause it to detach from the fixing device.
3. Spray CO test gas for approximately 1 second. The test cap must remain over the detector until it activates. The distribution of CO test gas in the cap and thus the sensor activation time can take up to 20 seconds.
4. Both detection areas are covered by the test cup, so both optical sensors are activated simultaneously.
5. The detector activates the alarm, and the red alarm LED flashes.

Option 3

The detector can be tested during normal operation using a test device with a magnet. Warning! Ensure that the alarm does not trigger reactions in higher-level systems. Programmed activations of the central unit are stored and executed.

The figure indicates the position of the reed switch (pos. R) in OC detectors. Assuming the LED is positioned at 12 o'clock, the reed switch (pos. R) will be approximately at 2 o'clock.

Figure 5.1: Reed switch position

1. Bring the magnet close to the reed switch.
2. As soon as the reed switch is activated, the detector's LED emits a flashing green light once per second. The detector remains in test mode for 60 seconds with automatically set test parameters (e.g., reduced delay time to 15 seconds). The green LED flashes for the entire duration the detector is in test mode.
3. Place the test device under the detector so that the test cup is level with the sealing ring and seals tightly. If both scattered light areas are covered, both optical sensors are activated simultaneously (O test gas is not required).
4. The detector activates the alarm, and the red alarm LED flashes.

Warning! In case of programmed intermediate alarm storage, longer activation times may occur.

Verification Procedure for FAP-O 520 Detector

Option 1

Use the remote functional test to test detectors. Warning! Remote functional testing is only permitted if performed in accordance with the manufacturer's approved test procedure.

Option 2

1. On the fire alarm control panel, switch the detection zone to test mode. This automatically sets the detector to test mode and prepares it for testing.
2. Place a sufficiently large object (e.g., the test device or the detector replacement device) in both scattered light areas until an alarm is triggered. O test gas is not required.

Option 3

The detector can be tested during normal operation using a test device with a magnet. Warning! Ensure that the alarm does not trigger reactions in higher-level systems. Programmed activations of the central unit are stored and executed.

The figure indicates the position of the reed switch (pos. R) in O detectors. Assuming the LED is positioned at 12 o'clock, the reed switch (pos. R) will be approximately at 2 o'clock.

Figure 5.2: Reed switch position

1. As soon as the reed switch is activated, the detector's LED emits a flashing green light once per second. The detector remains in test mode for 60 seconds with automatically set test parameters (e.g., reduced delay time to 15 seconds). The green LED flashes for the entire duration the detector is in test mode.
2. Place the test device under the detector so that the test cup is level with the sealing ring and seals tightly. If both scattered light areas are covered, both optical sensors are activated simultaneously (O test gas is not required).
3. The detector activates the alarm, and the red alarm LED flashes.

Warning! In case of programmed intermediate alarm storage, longer activation times may occur.

Repairs

In case of a fault, the entire module/device must be replaced.

Disposal

Unusable electrical and electronic devices/modules must not be disposed of with household waste. Disposal must be carried out in accordance with applicable regulations (e.g., WEEE in Europe).

Packaging film for fire detectors with C sensor: Multi-sensor detectors with C sensor are packed in a wear-resistant PE-ALU laminated film, which can be disposed of with household waste.

Technical Data

Detector and Sealing Ring

Environmental Characteristics

Mechanical Characteristics

Detector Base

Mounting Boxes

FAA-500-BB Rear Housing for Ceiling Mounting

• Mounting Dimensions:
• Suspended Ceiling Thickness: Max 32 mm
• Required Hole Diameter: Ø 130 mm (tolerance -1 mm to +5 mm)
• Installation Height: 11 cm
• Max Cable Diameter: 1.4 cm
• Color and Material: Polypropylene/White
• Dimensions (Ø x A): 140 x 104 mm
• Weight (without/with packaging): Approx. 100 g / 200 g

FAA-500-CB Integrated Housing for Concrete Ceilings

• Color and Material: Plastic/polystyrene, Gray
• Dimensions (Ø x A): 218 x 103 mm
• Weight: Approx. 340 g

Appendix

Abbreviations

Product Codes

Detector and Sealing Ring

Colored Inserts for FAP-O 520-P, FAP-OC 520-P, and FAA-500-TR-P Detectors:

Detector Bases / Remote Indicators