Posted on 11th April 2017
Calibration gas supply to the global shipping industry is a rapidly growing market. So, what exactly is calibration gas used for and why is calibration so important when it comes to maritime safety? In our two-part blog, we take a look at some of our most commonly asked questions relating to calibration gas.
What is meant by the term ‘calibration of an instrument’?
In simple terms, calibration means adjusting an instrument, or piece of equipment to meet a defined specification. Calibration Involves checking, by comparison with a standard, the accuracy of a measuring instrument. Calibration may also include the adjustment of the instrument to bring it into alignment with the standard.
What is a calibration/span gas?
Calibration gases, such as also known as span gases, are gas mixtures which are used as a referencing tool, acting as a comparative standard in the calibration of analytical instruments, such as gas analysers or detectors. Exposing a detector, or analyser to a verified concentration of test substance, will guage whether the sensors respond accurately to that gas. Given their use, calibration gases must be exact and therefore have to be traceable to a national or international standard.
How and why is calibration/span gas used on ships?
Calibration/span gas is used to maintain safety conditions on ships, as gas detection and measurement is important for the vessel and the safety of its crew. Exposure to excessive amounts of toxic substances, or an environment that is deficient of oxygen, may cause workers serious harm and even death in extreme cases.
Combustible gas explosions can be incredibly dangerous and in the worst cases may seriously injure, or even kill crew and destroy property onboard a vessel, as well as damage the vessel itself. Regular tests using calibration gases are intended to protect crew from unknown hazards that may be present on the vessel.
Tests using calibration gases are typically used in the marine industry to; check and maintain safe levels of oxygen in enclosed spaces; monitor levels of oxygen in inert gas and within tanks; measure the flammability of hydrocarbon gas; measure levels of hydrocarbon gas present prior to entering pump rooms and other enclosed spaces, as well as locate and measure other potentially toxic gases within a ship.
Why is instrument calibration for gas detection and measurement so important?
To ensure accurate readings and to maintain the reliability of gas detector instruments, it’s essential that all gas detection and measurement instruments undergo a regular schedule of calibration and testing. All instruments, both fixed and portable, must be adequately checked before use and records must be kept of these checks, as well as details of any faults that may have been found.
Careful calibration is vital, as gas detection and analysing equipment will only give accurate readings if calibration is carried out in accordance with the instructions of the manufacturer and if the correct calibration gases are used. Instruments must always be checked, as well as be zeroed using pure gases such as nitrogen (99.999% N2) and spanned when necessary, in accordance with the manufacturer’s instructions.
Coming next week…
So, you now know what calibration is and why it’s so important in the maritime industry. That’s it for this week! Don’t forget to tune in for part two of our article next week, where we look at the types of instruments used for gas detection and measurement in the shipping industry, who’s responsible for calibration onboard ships, what gas mixtures and flow rates are used in shipping and what fresh ideas the leading calibration gas suppliers are bringing to the table, that are revolutionising calibration gas supply.