FGD-4500 Fixed PID VOC Gas Detector 10.6 eV Lamp 1 ppb Resolution 316L PEEK Cell

FGD-4500 Fixed PID VOC Gas Detector

The FGD-4500 is a fixed photoionisation detector for continuous VOC monitoring at fence lines, loading racks, solvent storage areas and wastewater headworks. It is designed for the low level measurements where flame ionisation detectors are impractical and where authorities require trend data at ppb concentrations. The upgrade addresses three common limitations: unstable low range readings, lamp windows that fouled quickly, and wetted parts that absorbed the very compounds being measured.

Higher Accuracy Than Previous Generation

• Accuracy improved from plus or minus 5% of reading to plus or minus 2% of reading using a stabilised lamp driver and an active zero reference.
• Resolution of 1 ppb below 10 ppm, allowing detection of fugitive emissions long before they reach odour or exposure thresholds.
• Response factors for common compounds stored in the detector, so readings can be reported in the correct gas equivalent instead of isobutylene only.
• Automatic zero and span check cycles reduce the drift that plagues low range PID measurements in humid ambient air.

Improved Detector Performance

• Response time T90 below 5 seconds with an internal pump sampling at 0.5 L per minute, capturing short leaks that a diffusion design would miss.
• Three relays configurable for alarm, warning and fault, with 4-20 mA and RS485 Modbus for SCADA integration.
• Field replaceable lamp and window, so a contaminated lamp does not require returning the instrument for service.
• Lamp intensity and cell cleanliness diagnostics reported over Modbus, supporting condition based maintenance.
• Continuous operation with automatic zero check, giving stable 24 hour trends for regulatory reporting.

Upgraded Materials and Construction

• 316L stainless steel flow cell with PEEK inner liner replaces the previous PTFE lined aluminium cell, resisting solvent attack and reducing compound adsorption on wetted surfaces.
• Sapphire lamp window resists scratching and chemical etching, keeping UV transmission stable over a longer service interval.
• 316L stainless steel housing with IP66 sealing for outdoor fence line and loading rack installation.
• Heated sample line option prevents condensation in high humidity sites, protecting the optical path.

Technical Specifications

Typical Applications

• Refinery and terminal fence line VOC monitoring
• Solvent and coating plant loading areas
• Wastewater headworks and aeration odour control
• Pharmaceutical and chemical storage warehouses
• Environmental monitoring stations near industrial zones

Calibration and Consumables

Calibration uses isobutylene standard gas at two concentrations, with recommended intervals of three months for clean service. Lamps, windows and filters are user replaceable. Response factors for benzene, toluene, xylene and other common compounds are supplied in the manual.

Ordering and Support

Each detector is supplied with a calibration certificate, sensor cartridge, weatherproof sunshade, mounting bracket and operation manual. Optional items include a calibration cup, duct mounting kit, remote display and HART or Modbus gateway. Our technical team supports configuration, bump testing schedules and spare sensor supply.

Contact our sales team for a quotation, datasheet or sample evaluation unit.