Mechanical Mounting and Environmental Placement
The GST I-9105R intelligent reflective infrared beam smoke detector combines both emitting and receiving optical elements into a single transceiver housing measuring 206 mm × 95 mm × 95 mm with an overall unit weight of approximately 1.3 kg. The detector is engineered for high-ceiling industrial and commercial interiors where standard point detectors prove difficult to maintain, particularly spaces where ceiling heights exceed 6 metres such as warehouses, logistics hubs, exhibition halls, and production facilities.
The detector supports two installation mounting methods:
- Direct surface mounting onto a flat, vibration-free wall or structural column via pre-drilled fixing holes secured with wall plugs.
- Flush mounting onto a standard two-gang electrical back box.
Because the unit possesses an IP20* ingress protection rating and an operating temperature threshold from -10°C to +50°C, installations must be situated in protected, indoor, dry environments free from direct water ingress or continuous condensation.
Optical Pathway and Reflector Mirror Planning
The optical beam path can span from 8 metres to 100 metres in overall length, providing lateral protection across a width of up to 14 metres and safeguarding a total coverage area of up to 1,400 m². The detector must maintain an entirely unobstructed line of sight to the passive honeycomb mirror assembly across the monitored zone.
Reflector panel quantities must be selected strictly according to optical distance:
- Short-to-Medium Path (8 m to 40 m): Requires 1 passive honeycomb reflector mirror panel mounted directly in line with the detector transceiver.
- Long Path (40 m to 100 m): Requires 4 passive honeycomb reflector mirror panels grouped together in a 2×2 square matrix opposite the transceiver.
Field Wiring and Electrical Connections
Field cabling must use fire-rated cables with a minimum conductor cross-sectional gauge of 1.0 mm². Two dedicated cable pairs are required to connect the detector:
| Terminal Pair | Circuit Function | Operational Parameters |
|---|---|---|
| D1, D2 | Operating DC Power Supply (Non-polarized) | 24VDC (±10%), 12 mA standby current, 22 mA alarm current |
| Z1, Z2 | Fire Alarm Communication Loop (Non-polarized) | 24VDC nominal loop voltage (15V to 28V operational range) |
| K11, K12 | Alarm Output Dry Contact | Normally open (NO), rated 28VDC / 2A for conventional panel interface |
| K21, K22 | Fault Output Dry Contact | Normally closed (NC), opens on fault or loss of power |
Optical Alignment and Calibration
The I-9105R incorporates an optical assembly capable of physical alignment adjustment across -6° to +6°. To ensure stability against false tripping and fault signals, the installation must achieve alignment within a maximum angular misalignment tolerance of ±0.5°.
The unit features visual signal strength indication, enabling single-person optical alignment without secondary meter equipment. Align the optics until the signal strength indicators confirm adequate optical return from the honeycomb reflector panel. Once set, the onboard microprocessor utilizes automatic drift compensation to absorb long-term signal degradation caused by dust accumulation, component aging, or minor building settlement.
Addressing and Commissioning
The unit operates natively on digital loops connected to GST intelligent fire alarm control panels (including GST200-2, GST5000, and GST-IFP8) or operates conventionally via the K11/K12 and K21/K22 dry contacts. For addressable loops, electronic addressing (code range 1 to 242) and optical sensitivity settings are assigned on site using the GST P-9910B handheld programmer prior to final panel loop registration and BS EN54 Part-12 compliance testing.
