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What are Calibration Gases?

9/30/2013 12:43:56 PM | by Anonymous

Calibration Gas

Calibration Gases are certified as gas mixes which are commonly called as span gases. They are utilized to ensure that the gas detectors are operating appropriately. The calibration is conducted by passing a known mixture of gases into the detector in order to verify that it is reading the concentration accurately. Instrumental calibration is a crucial step that is to be conducted daily, weekly and even monthly. It is dependent on the frequency of use of the detector and manufacturer’s requirements.

Calibration is an essential step to ensure that proper performance of gas detectors. The process requires the use of test gas known concentration which is also known as span gas. The incorrect usage of expired calibration gas can cause improper calibration to occur. This will in turn result in unsafe operations and inaccurate diagnosis of the instrumental malfunctions.

Non Reactive Gas Mixtures is a term used for chemicals that are stable under most of the conditions and they are not usually affected by oxygen, moisture or other possible chemicals. These non reactive gas mixtures are calibration gases mixtures which do not consist of any reactive gases. The non reactive gas mixtures consists of gases such as Nitrogen, Carbon Dioxide, Hydrogen, Carbon Monoxide, Propane, Ethane, Isobutylene, Methane, Pentane and etc.


However, reactive mixtures are calibration gas mixtures that consist of one reactive gas at the very least. Reactive gases would include Chlorine, Hydrogen Sulfide, Sulfur Dioxide, Hydrogen Chloride, Ammonia and etc. They are packaged into aluminium cylinders that would have been specially treated and passivated to minimize any possible reaction within the cylinder. However, these mixes usually have shorter shelf lives due to the concentration of the gas that dissipates.

Uses of Calibration Gases

1. These gases are used in most disposable gas cylinders that are used for calibration. They are normally calibration of portable gas detectors. The detectors are usually manufactured by various companies such as Industrial Science (ISC), RKI, MSA, BW Technologies. These detectors are used to determine toxic, flammable, combustible gases as well as oxygen depletion. They can be found in industries where work is conducted in very confined spaces. For examples, tanks, underground utilities, natural gas and oil refineries, natural gas and oil pipelines, firefighting and HAZMAT recovery.

2. These detection instruments help to detect the presence of combustible and toxic substances. Also, whether or not the surroundings is oxygen deficient or enrichment. Workers do not rely on their sense of smell to alert them of the hazards. This necessitates the use of detectors when a worker enters areas with potential hazards. Exposure to excessive toxic substances can cause workers serious health issues and likely even death. Combustile explosions can also be disastrous, injuring, destroying property and even killing workers.


Types of Cylinder Sizes

This mixture comes in different sizes which are dependent on the frequency and application of its usage. Many of these are used to conduct calibration of portable gas detectors. They are packed in small disposable cylinders. Reactive mixtures only come in aluminium cylinders that are typically 34 to 58 litres in height. Larger sizes are also made available.


  • Calibration Gases Shelves Life

Cylinder’s shelf life is under RKI’s warranty. The golden rule is that all steel cylinders are only permitted a three year shelf life nothing more. Whereas, for aluminium cylinders it is within six to twenty four months, similarly nothing more is permitted.


  • How to tell if it has expired?

Most or even all RKI instruments calibration gas cylinders would have imprinted the “Best when used by” date on the cylinders which consists of the month and year. Thus, this serves as an indicator that the cylinders cannot be used beyond this date.


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