Gas Station Combustible Gas Detection Solutions

As critical nodes in urban energy supply, gas stations handle the storage, refueling, and transportation of Liquefied Petroleum Gas (LPG), Compressed Natural Gas (CNG), and Liquefied Natural Gas (LNG). The primary hazard in these facilities is combustible gas. In case of leakage, exposure to flames, static electricity, or high temperatures can easily trigger fires or explosions, causing casualties, property damage, and environmental pollution. Recent frequent incidents highlight the importance of real-time, reliable gas monitoring in preventing major safety hazards.

According to national standards such as GB 50493-2009 (and its revision GB/T 50493-2019) "Design Specification for Combustible and Toxic Gas Detection and Alarm in Petrochemical Facilities," gas stations must be equipped with industrial-grade combustible gas detection and alarm systems to provide timely warnings within the lower explosion limit (LEL) range. Nexisense, as a professional gas detection brand, offers complete solutions from fixed online monitoring to portable inspections, helping gas station enterprises build multi-layered protection systems to achieve early detection, early handling, and zero-accident objectives.

Analysis of Combustible Gas Risks at Gas Stations

Common gases at gas stations include LPG (mainly propane C₃H₈ and butane C₄H₁₀, explosion limits 1.5%-9.5%) and natural gas (mainly methane CH₄, explosion limits 5%-15%). The densities of these gases differ significantly: LPG is heavier than air (about 1.5-2.0 times), tending to accumulate in low areas; natural gas is lighter than air (about 0.55-0.65 times), rising but still capable of forming explosive mixtures in confined spaces.

High-risk points are concentrated around storage tanks, refueling dispensers, unloading platforms, compressor rooms, and valve assemblies. Leakage causes include aging valves, loose joints, improper operation, or third-party damage. Civil-grade detectors suffer from large zero drift, slow response, and lack of explosion-proof design, failing industrial requirements. Industrial systems must have explosion-proof certification (Ex d IIC T6 Gb highest level), fast response (<30s), and stable output to ensure long-term reliable operation in humid, dusty, and explosive environments.

In practice, early micro-leakages are often difficult to detect, but accumulation can lead to severe incidents. Real-time LEL monitoring allows enterprises to activate ventilation, shut valves, or initiate emergency plans, greatly reducing accident probability.

Core Advantages of Nexisense Online Combustible Gas Detectors

The Nexisense SGA-500 series online combustible gas detectors are designed for high-risk industrial sites, using imported catalytic combustion or infrared sensors with strict secondary calibration, ensuring ±3%FS accuracy. The product complies with GB 50493, with CPA type approval, national explosion-proof certification (highest level), and third-party metrology certification.

Equipped with a 32-bit nano microprocessor and 24-bit high-precision ADC chip, the detector includes full-range temperature and humidity compensation, operating in -40℃ to +70℃ and up to 95% RH. Power supply is 12-30V DC with 4-20mA/RS485 dual outputs, supporting Modbus RTU protocol, ensuring long-distance stable transmission and compatibility with mainstream PLCs, DCS, and alarm controllers.

In gas stations, this series is ideal for monitoring LPG and natural gas leaks. Measurement range is 0-100% LEL with 1% LEL resolution; alarm points can be set at 20% LEL for first-level warning and 50% LEL for second-level interlock. Explosion-proof housing IP65+, corrosion- and vibration-resistant, suitable for outdoor installation. Compared to civil products, industrial sensors have longer lifespan (>3 years), lower zero drift, and faster response, avoiding false or missed alarms.

At a coastal LPG refueling station, deploying SGA-500 successfully detected multiple micro-leakage events, preventing potential explosions and significantly enhancing operational efficiency and compliance.

Sensor Technology and Installation Optimization

Catalytic combustion sensors are sensitive to various hydrocarbons, suitable for LPG/natural gas mixtures; infrared sensors are resistant to poisoning and oxygen interference, suitable for long-term unmanned operation. Recommended installation: detectors placed downwind of leakage sources, 0.3-0.5 m above ground for LPG or 1.5 m for natural gas, avoiding vents and direct sunlight. Regular bump testing and calibration ensure reliability.

Integration with Alarm Controllers for Complete Systems

The SGA-500 can seamlessly integrate with SGA-800 series alarm controllers, forming a distributed gas alarm system. Controllers provide centralized power, signal collection, and display, supporting line/bus modes, expandable up to 64 points. Concentrations are displayed in real-time, triggering graded audio-visual alarms and relay outputs to control fans, electromagnetic shut-off valves, or fire protection systems.

Controllers installed in front offices or control rooms allow personnel to view alarm points and concentration trends immediately. Data can be transmitted to cloud platforms for remote monitoring and historical traceability. Practical cases show this integration reduces response time to seconds, greatly improving emergency response efficiency.

System Interlock and Emergency Response

Level 1 alarm (20% LEL) activates audio-visual alerts and local ventilation; level 2 (50% LEL) cuts off gas supply and triggers emergency broadcast. Controllers support 4-20mA/RS485 for integration with existing SCADA systems for digital management.

Portable Detectors for Daily Inspection

While fixed systems cover main areas, inspections remain essential. The Nexisense SGA-600 portable combustible gas detector is small, lightweight, supports diffusion/pump sampling, measures instantly, displays LEL values, alarms automatically, and has 8-12 hours battery life.

Inspectors can carry the probe into valve pits, tank bottoms, and other dead zones to identify hazards. Combined with APP data uploads, inspection records are digitized for traceability and analysis.

Practical Tips for Inspections

Perform daily checks of critical areas, confirm sensor validity before bump tests. Data logs can be exported for monthly safety reports.

Overall Implementation Strategy for Gas Station Detection

Conduct risk assessment before implementation, identify high-risk points (storage tanks, refueling islands). Prioritize fixed monitoring in permanent areas, use portable devices for dynamic checks, and centralize management via controllers. Employee training should cover gas properties, alarm response, and device operation. Regular maintenance (quarterly calibration, annual full inspection) ensures system availability >99%.

Long-term, this investment significantly reduces accident probability, downtime losses, and enhances corporate safety image, meeting national safety and environmental standards.

FAQ

1. How to select sensors based on gas type? LPG (propane/butane) is heavy and accumulates in low areas; catalytic combustion sensors are recommended, 0-100% LEL, monitoring near ground. Natural gas (methane) rises; sensors can be installed higher, infrared type resists poisoning. SGA-500 series provides dual options for site-customized deployment, minimizing cross-interference. Explosion limit settings should consider gas composition and environment per GB/T 50493.

2. Installation location and height requirements? Storage and unloading areas should be downwind and low (LPG 0.3-0.5 m, natural gas 1.2-1.8 m breathing height). Dispenser areas should avoid vents to prevent dilution false alarms. Enclosures must meet Ex d IIC T6 Gb, IP65. SGA-500 supports wall/pipe mounting with maintenance space and quarterly inspection of seals and filters.

3. Portable detector battery and charging management? SGA-600 diffusion mode 10-12h, pump 8h, USB/charging dock, full 4-6h. Charge after inspection, avoid

   <20% battery="" affecting="" pump="" speed.="" low="" warning="" and="" data="" storage="">1000 logs). Hot-swappable batteries for multi-shift inspections. Daily bump test and recharge ensures continuous monitoring.

4. Alarm controller interlock with fans/valves? Relay output (NO/NC) and Modbus. 20% LEL triggers fan, 50% LEL cuts solenoid. Supports zoning, graded alarms, custom delays. SGA-800 expandable to 64 points, RS485 integrates with PLC. Typical: tank leak triggers forced ventilation + audio-visual alarms, reducing spread risk.

5. System integration with SCADA or remote platforms? Supports 4-20mA/RS485 Modbus RTU/TCP. Gateway connects to SCADA for real-time curves, alarm logs. Data can feed ERP for compliance audits. Recommend network encryption/isolation. Many stations digitize operations, reducing manual inspections and improving traceability.

6. Protection and maintenance in humid/dusty outdoor environments? IP65+ recommended, corrosion-resistant enclosure. Maintenance: monthly filter cleaning, quarterly bump + zero/span calibration (standard gas), sensor lifespan 2-3y. Check seals for condensation. High pollution zones: monthly calibration. Log maintenance to maintain ±5% accuracy.

7. Emergency response and post-event analysis? Use SGA-600 portable to map concentration, mark danger zones (>20% LEL evacuate), activate fixed system ventilation/shutoff. Wear protective equipment. Export logs (peak, trigger time), analyze causes (valve faults). USB/Bluetooth reports facilitate accident documentation and improvement, e.g., adding sensors or optimizing inspection routes.

8. Investment ROI evaluation? Initial cost: detectors, controllers, installation (~60% of total). Benefits: avoid downtime from accidents (single explosion up to millions), fines, insurance reduction, efficiency gains (real-time optimization, 5-15% energy savings). ROI usually 1-2 years; many stations report >40% reduction in hazards. Consider sensor replacement (10-15% annual) in long-term ROI.

Conclusion

Gas station safety is a matter of public interest. Combustible gas leak risks can be effectively managed through a scientific monitoring system. Nexisense SGA-500 online detectors, SGA-800 controllers, and SGA-600 portable devices form a closed-loop solution covering fixed monitoring, centralized management, and dynamic inspection, ensuring compliance and fast response. Early deployment prevents major accidents and provides a solid foundation for stable operations and sustainable development. Customized configurations based on site assessment are recommended to build an optimal gas safety defense.