Calibration Gases: Instrument Accuracy Ensures Consistency and Safety
Safety is a priority when working with dangerous gases. Whether you are mining or manufacturing, working in a research lab or university, instrument calibration provides accurate and consistent measurements and can save lives. Toxic gas build-up in an enclosed environment can become lethal. Workers rely on properly functioning instruments to warn them of dangerous conditions. Calibration gas or gas mixtures are used to calibrate gas analyzers, gas monitors, and gas detectors. This process ensures that instruments perform optimally. Important things to consider when conducting the calibration are the gas category, gas quality, delivery and storage, and frequency needed.
The Calibration Process and Gas Category
The International Safety Equipment Association, defines gas calibration as, “The adjustment of the sensor(s) response to match the desired value compared to a known traceable concentration of test gas.” Traceable calibration gases train instruments to read correctly by introducing them to known values.
Calibration gases are divided into two categories: zero-calibration and span calibration. Zero-calibration gas mixtures contain no flammable gas and obtain a baseline reading. They “zero” out the instrument and remove any target gas or other cross-sensitivity. Span calibration gas mixtures are a precisely composed concentration of detectable gas exposed towards the gas detector or gas analyzer. It’s a sensitivity adjustment. Gas quality matters when conducting the calibration. It’s important to know the gas purity, as it makes a significant difference.
Gas Quality and Gas Selection Make a Difference
Gas impurities affect the calibration outcome. Helium, nitrogen, argon, hydrogen, oxygen, carbon dioxide, and acetylene must have a determined purity to function properly in an analyzer. Nitrogen is a conventional calibration gas and may need to be determined as pure as 99.9995%. Calibration gases need to be gravimetrically produced and traceable to the National Institute for Standards and Technology (NIST). Traceability and certification act as proof of accuracy verification. Function testing gases have a wide range of applications depending on the industry. Calibration gas manufacturers should produce customized gas mixes that align with your specific applications. There is typically, no one-size-fits-all approach. It’s important to work with a provider that takes the time to learn about your business and provides appropriate recommendations for gas shipping and storage.
Gas Delivery and Storage
It’s important to carefully assess the amount of gas required for calibration because gases must be contained and readily available at the point of testing. Each gas cylinder should be prepared and validated for stability and homogeneity of the product. Safe and proper handling of stored gases is essential to decrease the health and environmental risks associated with transporting and storing. Storage containers for laboratory and calibration gases include cryogenic cylinders (Dewars), gas cylinders, and glass bottles (ampules). Calibration is a repeated process, so it’s important to ensure there is a long-term plan in place. Your industry and instruments will dictate the need for size of delivery and long-term storage.
Regular Instrument Calibration is Needed
There are no strict guidelines for calibration frequency. Everyone should follow the manufacturers’ recommendations, but the process is necessary to avoid calibration drift. This drift affects accuracy and is caused by factors such as instrument age, environment, rough handling, and neglect. Some industries calibrate once a month, while others calibrate once a year. New instruments should be calibrated before use, as well as instruments that experienced an unexpected shock or vibration. The risks of not calibrating instruments regularly include inconsistent readings and results, wasted materials, damaged equipment, violation of industry regulations, and worker accidents or injuries.
Calibration Gases in the Rocky Mountain Region
Technological advances increase the need for applications that require specialty gases and accurate, safe, and consistent instruments. Rocky Mountain Air is committed to providing our customers with high-quality products, outstanding customer service, and flawless dependability. We provide pure, traceable, and precise calibration mixtures. If you have any questions regarding gas calibration, please contact your local RMA branch in one of our five states (Colorado, Idaho, Nebraska, Utah, Wyoming) today. We look forward to serving you!
