If there is one crucial element for the oil & gas industry, it is the calibration gases. These gases are used as reference materials in analytical instruments of gas measurement like gas detectors and gas analyzers. They enable precise measurements to be made for these devices. These gas mixtures must meet several demands to be used as calibration standards. Many people may wonder what makes them different. We will address the varieties of calibration gases here.
What Is Calibration Gas and why is it important?
Calibration gas is a compressed gas mixture that is used for the calibration of many detecting instruments. It is basically a gas mixture that ensures gas analyzers and gas detectors work efficiently. The calibration gas must to pegged to a national or an international standard to make it usable and calibrate other critical equipment for gas analysis and gas detection.
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Calibration gases are segregated further into two groups: zero-calibration and span-calibration. A zero-calibration gas is the usual one as they are a gas mixture with no flammable gases and they are of much use when gas detectors have a certain analyte structure which is not usually responded to by gas detectors.
Next comes the span calibration gas with its advanced properties, as it is detectable with its gas concentration that can be precisely used for gas detectors and gas analyzers.
Types of calibration gases
Each type of calibration gas has its own unique mixture, which is known as a volumetric gas mixture. In general, a volumetric gas mixture is created by measuring the pressure of each gas as it enters a pressure gauge and determining the quantity of each gas added. Each individual gas occupies a certain amount of space in a volumetric mixture, and the mixture ratios can change as the pressure and temperature change. Compressibility differences can occur in each mixture as the environment changes, so the certification is only valid at the certificate’s specified temperature and pressure. To ensure proper use, a compressibility correction should be made if the mixture is used outside of these conditions.
A gravimetric gas mixture is a special gas mixture whose components are weighed using precise scales. The mole and mass percentages are independent of pressure and temperature in this type of mixture. To determine how precise the mixture is, a balance scale is used. The purity of raw materials determines how precise the gas mixture is produced.
Essential things to keep in mind while calibration of instruments:
Even when you’re super careful, a few things will get overlooked sometimes. It’s not a great thing when you’re dealing with potential toxic gases and the safety of your employees. These reminders will help you ensure that your gas testing is thorough.
Here are some useful reminders to make sure your gas testing is as comprehensive as possible. When testing with calibration gas, always make sure that the device is zeroed in fresh air (such as in an office environment). Calibrations should be done at least monthly. Before using the detector, calibrate it daily. Verify sensor reading match with the calibration gas cylinder label concentration (incorrect concentrations can cause inaccurate readings). Use the correct regulators and fittings to deliver calibration gas to an instrument, or incorrect flows will cause inaccurate readings. Don’t be afraid to get an expert opinion if you’re uncertain about a calibration phase or the gas you’re using.