5 Different Types, Functions, and Components of Calibration Gases

Among the most diverse product lines in the specialized gases portfolio are calibration gases, and they’re usually manufactured to order. They’re used to confirm that analytical instruments are working properly and that measurements are correct.

A reference gas or combination of gases is a starting gas that makes up the composition, which is then increased by one or more components.

Below are the types, functions, and components.

Air Quality Monitoring

The most frequent calibration gases combination used by Australia’s Environment Protection Authorities for outdoor ambient air quality monitoring is a mixture containing 50ppm NO, 50ppm SO2, and 0.5% CO in nitrogen equilibrium. 

The US Environmental Protection Agency validates the calibration gas mixtures manufactured at various specialised gas filling plants imported by the Environment Protection Authorities in several Australian states and territories.

Because the concentrations of polluting gases in specific air quality monitoring applications are low, the apparatus employed will require calibration at lower levels than the above combination. Therefore, experts can provide ISO/IEC 17025-accredited calibration gas mixtures with lower typical contaminant concentrations for these applications.

Automotive Emission 

The following two gas mixes are often used for testing roadside heavy-duty vehicle emissions monitoring systems. On most emissions measurement devices used in this application, the first mixture is a low-level mix and the second mixture is a high-level mix at about 90% of full-scale deflection. It contains 0.15% CO, 100 parts per million propane, 0.6% CO2, 21% O2 nitrogen balance, 0.9% CO, 600 ppm propane, 3.6% CO2, and 21% O2 nitrogen balance.

The two mixes mentioned above will also be known as:

  • CO concentration of 0.15%, propane concentration of 100 parts per million, and CO2 balance air concentration of 0.6 percent
  • CO: 0.9%, propane: 600 ppm, CO2: 3.6% balance air

Blood Gas Analyser

The calibration gas mixtures required will vary depending on the equipment being utilised and the tests being performed. To produce a calibration curve for the device, two or three calibration gases are commonly used. Some quality standards will need instrument calibration both before and after testing. Calibration will be done once a day or once a shift in other quality systems.

Breath Alcohol 

The Australian police employ breath alcohol concentration (BAC) testing in both private and corporate contexts. Most Australian police agencies impose a blood alcohol concentration of 0.05 grams (50 milligrams) per 100 milliliters (ml) for most drivers.

Breath alcohol calibration gas mixes that are often used are 

  • 25 parts per million ethanol, balance nitrogen 
  • 155.7 parts per million ethanol, balance nitrogen 
  • 210 parts per million ethanol, balance nitrogen 
  • 220 parts per million ethanol, balance nitrogen

BTEX Calibration 

The components benzene, toluene, ethylbenzene, and xylene make up this category of calibration mixes. They are used for gas detection and air quality monitoring, particularly in the vicinity of petrochemical plants.

These VOCs are frequently required in calibration gas mixes at the following concentrations:

Gas detectors used in refining, petrochemical processing, and petrochemical tank storage activities must have a detection limit of 100 parts per million (ppm) and 1 ppm for air quality monitoring, such as by environmental scientists or perimeter monitoring in the petrochemical industry.

A zero gas, such as 5.0-grade nitrogen or zero air, will be required in addition to a calibration gas (bump test gas or span gas) to establish the zero reading on the gas detection apparatus.

Gas detector calibration applications frequently use portable cylinders for calibration gas mixtures.