Infrared vs Catalytic Gas Detectors

Posted by Claire Allcock on 28th May 2020

Catalytic and Infrared gas detectors are both excellent options for gas detection; however, in some situations, one detection system is better suited than the other. Today we’re weighing up the pros and cons to Infrared and Catalytic gas detectors!

Environmental Factors to Consider

There are many factors to consider when weighing up your options. Both infrared and catalytic sensors have situations that they are better suited to. This comes down to the types of gases you need to detect, as well as your working environment.

Site Environment

Both IR and catalytic detectors are capable of functioning long-term in the harshest of environments. Both detectors should still be checked with gas (during a bump test), as well as splash guards and dust shields being checked for blockages — showing no significant differences in overall maintenance requirements.

In climates with temperature extremes, humid conditions, and around hot or vibrating machinery, catalytic detectors are the best choice.

Calibration

Both catalytic and IR detectors rely on regular calibration in order to stay accurate. However, they both feature an automatic calibration adjustment sequence with no tools or area declassification necessary; just activate the process and apply the calibration gas.

Detector Placement

There are three types of monitoring strategies; point, area and site perimeter. Once you have pinpointed the location of a potential gas leak, you can design a point monitoring strategy that will detect gases at the source point. This ensures that gas detection is as fast as possible, minimising possible harm to personnel and the environment.

For areas where the gas source is harder to identify, a wider area monitoring system must be used, placing detectors at preset distances to keep the environment covered. Depending on your situation, you may also need perimeter monitoring to monitor gases that pass across your property boundaries. In these cases, open-path IR detectors can be useful for detecting gases that can become airborne.

Life Expectancy

Both catalytic and IR gas detectors have a sensor life expectancy of up to five years. Catalytic detectors can be calibrated 50 times with one cylinder of gas, whereas IR detectors require no routine calibration; however, if calibration is performed, they are limited to 10 times maximum per cylinder of gas.

Cost

The initial cost of catalytic detection is typically lower than IR, but overall IR maintenance costs are lower. Both IR point detectors and catalytic detector/transmitters share similar installation and wiring costs. Inspection frequency is the same for both, but IR detectors feature self-diagnostics while catalytic detectors require a gas check. IR detectors do not require routine calibration, however 90-day gas checks are recommended.

In many circumstances, repair data shows catalytic detectors may be more quickly repaired in the field than IR detectors that often require factory expertise for repair. This minor inconvenience, however, is easily overcome by keeping a spare IR detector on hand to be used in the unlikely event that repair is needed.

Performance & Reliability

While IR detectors do offer enhanced reliability due to their fail-to-safe style, immunity to poisons, and ability to function without oxygen, catalytic detectors offer application flexibility, simple maintenance and low replacement costs.

Both technologies are reliable, fast detecting and accurate. Neither is necessarily the answer to everything, and in most plants, a combination of both types is the correct and sensible solution.

There is clearly a strong need for both catalytic and IR gas detectors; it’s important to understand your specific needs and requirements before making a decision. Use the DSA Suppliers’ many years of experience to help you choose the right gas detection system for your unique environment.