Gas Sensors for the Chemical Industry: How to Choose the Right One

Industrial facilities handle gases that can ignite, poison, or suffocate. Without regular calibration and maintenance, gas detection becomes unreliable — and potentially dangerous.. Governments and industry bodies enforce rules to ensure:

• Sensors respond fast enough to prevent exposure
• Devices operate safely in hazardous areas
• Equipment integrates with facility-wide alarms
• Workers receive clear and early warnings

These requirements are not optional. Ignoring them may lead to penalties, insurance issues, or serious accidents.

Every chemical plant handles specific substances. Some are flammable (like hydrogen), others toxic (like chlorine or ammonia). A sensor not designed or calibrated for the specific target gas will not detect it, except in cases of cross-sensitivity.
Before purchasing any equipment, define:

• Types of gases in use or generated
• Their concentration levels
• Whether they are explosive, corrosive, or asphyxiating
• Exposure limits set by regulations

This forms the baseline for selecting both the sensor technology and detection range.

Gas detectors must perform reliably in field conditions, not lab conditions. The gas detectors for chemical plants you select should withstand:

• High humidity and temperature fluctuations
• Dust, solvents, or corrosive fumes
• Places with pressure changes or poorly ventilated enclosed spaces
• Electromagnetic interference from nearby equipment

Sensors must also have the correct IP rating and, if needed, explosion-proof enclosures.

Each gas sensor type offers specific benefits. The most common choices include:

• Electrochemical: Suitable for detecting toxic gases; accurate but sensitive to temperature.
• Infrared (IR): Ideal for flammable hydrocarbons; stable and less prone to contamination.
• Catalytic bead: Low cost for flammable gas detection but can degrade in harsh environments.
• Photoionization (PID): Good for low-concentration VOCs but not suitable for all gas types.

Choose based on the gas properties, detection goals, and available maintenance resources.

Here’s a checklist to guide your decision:

• Gas type compatibility
• Sensor lifespan and calibration needs
• Alarm thresholds and response time
• Installation method (fixed, portable, wireless)
• Integration with DCS or safety systems
• Compliance with ATEX, IECEx, or local safety standards
• Availability of service and spare parts

Make sure the model fits into your plant’s existing safety architecture.

When selecting sensors, companies often focus only on price or delivery time. This approach causes problems later. The most common mistakes include:

• Using sensors for the wrong gas type
• Installing detectors in the wrong locations
• Skipping calibration schedules
• Ignoring sensor degradation in corrosive environments

Choosing uncertified equipment for hazardous areas

To be effective, gas detectors must be placed in the right locations. Use these basic guidelines:

• Near potential leak sources: pipelines, valves, storage tanks
• At gas-specific height: lighter gases (e.g., hydrogen) near ceilings, heavier gases (e.g., chlorine) near floors
• In enclosed or poorly ventilated zones
• Along airflow routes where gases may spread
• Where personnel exposure is likely

Also consider redundancy in high-risk areas.

A proper sensor system ensures:

• Early leak detection before dangerous concentrations accumulate
• Reduced risk of fire, explosion, or exposure
• Compliance with health and safety regulations
• Improved insurance coverage and audit readiness
• Greater confidence among operations staff

Use this method to streamline your decision:

1. Define your gases and plant conditions
2. Select sensor technology based on gas type
3. Ensure certifications match your safety zone classification
4. Match output signals with your control systems
5. Plan for long-term maintenance and calibration