What Are the Different Types of Calibration Gases?

Gas detection systems alert your team members to facility hazards. When the atmosphere becomes a safety risk, alarms sound so employees can clear the area or take proper measures to eliminate the issue. While detection systems keep people alert, they’re only as good as the calibration gases used to maintain them.

Test gases ensure your equipment performs as intended in whatever industrial or research space you monitor. The right gas mixture supports reliable sensor readings and regulatory compliance. Facility managers and industrial operations must understand their calibration gas options to protect their environments.

What Are Calibration Gases?

Calibration gases are gas mixtures that allow facilities to test and adjust gas detectors. Each mixture has a specific concentration of a target gas. It’s designed to mimic a real-world hazard or condition. 

Technicians then expose the sensors to the calibration gas. If the sensors register the mixture at the correct levels, teams know the devices work correctly. If not, technicians will adjust the sensors to detect gases accurately.

Facilities might use calibration mixtures during sensor calibration, maintenance and routine bump testing. You should employ test mixtures any time you need to test gas detection instruments. Inaccurate readings or poorly calibrated sensors can lead to false alarms and hazard exposure, risking team safety.

Types of Calibration Gases

Explore the two main types of calibration gases below:

• Zero gas: Zero gas has no measurable amounts of contaminants or target gas. It’s composed of nitrogen, purified air or another inert gas. Technicians use it to establish a baseline for sensors. Testing zero gas ensures detectors are not picking up residual gases or background influences that could skew readings. 
• Span gas: Span gas used for calibration contains a measurable target gas concentration. The sensor should be able to detect the gas at the correct levels. If not, technicians will fine-tune the detector’s sensitivity to trigger at the proper threshold. 

Types of Calibration Gas Mixtures

Testing mixtures come in single or multi-gas options. Single-gas mixtures work well for equipment targeting one specific hazard. Facilities should use multi-gas blends for fixed or portable monitors designed to detect multiple threats. The formula you select will depend on your equipment and needs.

Commonly Used Calibration Gases

Calibration gases are chosen for their inert properties or real-world presence and risk. Common gases include the following:

• Nitrogen
• Oxygen
• Carbon monoxide
• Hydrogen sulfide
• Methane
• Ammonia

Purity Levels and Regulatory Compliance

The accuracy of your calibration depends on the gas’s purity. Impurities can introduce measurement errors or degrade sensor performance over time. 

Groups like the National Institute of Standards and Technology (NIST) have standards for gas traceability, so your operation can be sure it gets mixtures from a reputable source. These traceability certifications protect your facility from impure gases and ensure you can accurately monitor your atmosphere. 

Span Gas vs. Zero Gas

Span and zero gases are both used for calibration in different areas. Zero gas establishes the baseline for sensors. This is the first step in the calibration process. 

Technicians can use a zero or inert gas to get their monitor to start at true zero before testing. They use span gas to test the detector’s ability to measure the specific gas levels that require monitoring. Then, they compare the sensor’s response to the known concentration in the gas to verify accuracy. If it’s inaccurate, they’ll make adjustments.

The key difference between zero and span calibration is that zero calibration uses zero gas to establish a baseline. Span calibration is performed after zeroing and uses span gas to set the instrument’s detection thresholds.

Choosing the Right Gas for Calibration

Span and zero gas are integral to a two-point calibration process. But you still need the right gas within those categories. 

When choosing your test mixture, consider these factors:

• Gas compatibility: The gas mixture should match the gases your detector is designed to measure.
• Concentration levels: Use a span gas concentration close to the expected alarm or sensor operational range. Too high or too low can lead to inaccurate calibration.
• Purity: Choose certified gas mixtures to meet industry traceability and purity standards.
• Supplier: Work with reputable suppliers to ensure high-quality mixtures and fast delivery.
• Regulatory requirements: Look for gases that meet industry-specific guidelines to remain compliant.

How to Use Calibration Gases

Calibration gases are used heavily in manufacturing and gas industries. Any operation dealing with hazardous atmospheric chemicals, substances or gas derivatives needs these mixtures. 

Additionally, various types of lab equipment need accurate gas detection to analyze samples correctly. Test gases ensure detection equipment is working properly. 

If there are leaks at facilities or hazardous gases are involved in production, your operation needs calibration gases. Proper procedures and safety practices protect teams from potential harm.

Instrument Calibration Procedures  

Bump testing and full calibration are two verification procedures:

• Bump testing: Known gas concentrations are applied briefly to the sensor. This test confirms that the detector and alarms respond as expected.
• Full calibration: This process involves the complete two-step process. Technicians zero the sensor and then use span gas to adjust the accuracy.

Calibration Gas Safety Guidelines   

Proper handling and storage are also essential when working with test gas. The Occupational Safety and Health Administration (OSHA) and the International Standards Organization (ISO) provide guidelines for testing detectors and handling gases:

• OSHA: OSHA recommends that each operation create standardized calibration procedures to ensure a safe environment. They also emphasize the importance of proper training and tools when dealing with calibration gases. Facilities should only use traceable gas for their testing.
• ISO: The ISO provides guidelines for storing, transferring and handling calibration gases. They must be stable and handled carefully to avoid impurities and operator harm.

Your facility should have access to relevant industry materials to create and maintain safe gas procedures. Some best practices include:

• Sourcing gases from reputable providers with traceable stock.
• Storing gas cylinders upright and securely to avoid tipping.
• Labeling gases clearly.
• Checking expiration dates and cylinder pressure regularly. 
• Wearing appropriate protective gear when handling cylinders. 
• Documenting all maintenance checks and calibration procedures for audits.

Turn to Meritus Gas Partners for Your Calibration Gas Needs 

Meritus Gas Partners delivers when you need reliable, accurately mixed calibration gases. With a range of gases — including specialty products — we help industrial customers confidently meet their safety goals. We provide certified purity and fast delivery.

What sets Meritus Gas Partners apart is our local expertise, product quality and responsive support. Our network of independent gas distributors combines technical knowledge with personalized service so you get exactly what you need every time. 

Contact us for custom calibration gas solutions and tailored recommendations. Meritus Gas Partners is here to help you every step of the way.