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Below you’ll find answers to the most frequently asked questions we get about non-refillable canisters.

What are non-refillable cylinders?

Non-refillable canisters (also called disposable cylinders) are those specifically designed for one-time use and should not be refilled or reused. Their portability and ease of use make them ideal for applications such as function checking of gas detection equipment, instrument calibration, laboratory use, and field based applications.

Like all calibration gases manufactured by Air Products, our non-refillable canisters are issued with a traceable Certificate of Analysis in accordance with ISO 6141. A range of simple-to-use gas control equipment and accessories provide a complete solution.

Which gas mixtures are available in non-refillable canisters?

Air Products supply an extensive range of mixtures in non-refillable canisters, using gases including Oxygen, Nitrogen, Hydrogen, Carbon Dioxide, Ammonia, Methane, Butane and more. Many common mixtures used in gas detection, landfill gas analysis, food atmosphere analysis and refrigerant leak detection are available from stock.

What is 'bump' testing?

Bump testing is a qualitative testing of gas detection equipment that involves a detector being exposed to a target gas at a concentration high enough to trigger all alarms, verifying that the alarms and sensors are working. Bump testing should be carried out prior to every use of gas monitoring equipment.

Failure of gas detection equipment can be very dangerous – portable instruments are particularly vulnerable due to the nature of their use. Sudden failure of the detector does not result in an alarm state, which may result in a 'non-reading' situation in the event of a gas leak, or build up of a hazardous atmosphere.

Bump testing is usually carried out by the operator using the gas detection equipment, rather than by a technician in a calibration workshop. Non-refillable cannisters offer greater flexibility and convenience and can be used at dedicated ‘bump test stations’ or out in the field.

What are the benefits of using non-refillable canisters versus traditional refillable canisters?

The main advantage of non-refillable canisters compared to traditional refillable canisters is portability, enabling regular bump testing to be carried out in the field, in addition to intermittent quantitative calibration in the workshop or laboratory. They are easy to use because no tools are required to connect the gas control equipment to the canister. There are no monthly rental costs or facility fees to consider, thus reducing the costs and hassle associated with having speciality gases on site. Transportation costs of non-refillables also tend to be lower than for conventional canisters.

How much gas do the canisters hold?

There are four non-refillable canister size options. The largest non-refillable canister holds approximately 110 gas litres. The smallest, aerosol-type canister provides 10 gas litres. Compare this to the gas capacity of a traditional 50 litre refillable canister, filled to 200 Bar, which gives 10,000 gas litres. Non-refillables are ideal where smaller quantities of gas are needed.

How many bump tests can I get from a canister?

There are a number of factors that affect the number of bump tests achievable from a single non-refillable canister. These include:

  • The flow rate of the gas required by the instrument. The manufacturer of the instrument will normally recommend the optimum flow rate in their operating procedures. Selecting a suitable fixed flow regulator from a wide range will maximise the number of bump tests possible from the canister.
  • Using a demand-flow type regulator with instruments fitted with internal pumps further optimises the process. These units limit the flow of gas to that demanded by the instrument. This means there is no wasted gas and no need for T-piece arrangements.
  • Using compatible regulator materials and keeping lengths of tubing as short as possible speed up instrument response time. Air Products supply a short length of compatible tubing with each regulator package to ensure best results.
  • Instrument response time and the sensor technology – these characteristics can be found in the manufacturers operating manual.
  • Many manufacturers offer instrument ‘docking stations’, which automate the bump testing or calibration procedure and help keep gas usage to a minimum.

The largest non-refillable canister in the Air Products range holds 110 gas litres. An instrument with a response time of 10 seconds using a fixed flow of gas of 1.0 lpm might be tested several hundred times using one such canister.

Do I pay rental on non-refillables?

No, there are no rental charges associated with non-refillable canisters.

What are the LEL values of flammable components?

‘LEL’ is the lower explosive limit of a gas which is an important characteristic of flammable components in the field of gas detection. Users wishing to test flammable gas sensors should be aware that there is more than one standard for determining the lower explosive limit of flammable components. The ISO 10156:2010 and IEC 60079-20:2000 standards are both commonly referred to in different areas of industry and in different world regions. For most components, the quoted LEL values are the same, but there are a number of important differences. As these international standards are reviewed and updated over time, make very sure you order the correct gas mixture by requesting the volume percent level, because in some cases, requesting a percentage LEL is ambiguous.

What are calibration gases?

A calibration gas is a reference gas or gas mixture (generally compressed) that is used as a comparative standard in the calibration of gas analysers and detection equipment. To be a calibration gas, the gas must be traceable to a national or international standard.

How do you calibrate a gas detector?

Calibrating a gas detector involves adjusting/resetting the sensor’s response against a known concentration of gas (a calibration gas). The method of calibration will depend on the type of equipment/technology you are using. How often you need to calibrate equipment will depend on the type of detector, its age, and any safety regulations. Always ensure you have the correct tools and accessories necessary for calibration before getting started, and refer to the instruction manual for the steps you need to follow.

Calibration steps:

  1. Connect the regulator to the calibration gas canister. Screw the bottom part of the regulator on top of the calibration gas canister and connect the sampling hose to the top connection of the regulator.
  2. Attach the airtight clip to the gas detector. Make sure the gas types as described on the gas detector match the ones as described on the clip.
  3. Connect the sampling hose to the clip and check if the entry of the gas will point in the direction of flow as described on the clip.
  4. Face the calibration gas canister and regulator and turn on the gas detector while opening the regulator. A first *beep* will sound. After a few seconds, the detector will sound its internal alarm as a result of the gases flowing through the clip.
  5. Turn off the alarm of the gas detector and close the regulator. Detach the gas detector of the sampling hose, and unscrew the regulator of the calibration gas canister.
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"Our business relies on simple bump testing of gas detectorson board marine vessels. Complex high pressure cylinders and regulators would make the job too difficult but we find the Air Products non-refillable offerings very easy to use and the equipment is simple to operate."

GMS Instruments, Rotterdam

"We are involved in the installation, commissioning and maintenance of a wide range of gas detection equipment into many market sectors. The fact that the Air Products’ range covers all of the flammable, toxic, quad-gas and corrosive gas requirements for this market is very important to us."

Autochim, France

"Personal, portable and fixed gas detection equipment is widely used in many safety critical applications and these items are often subjected to relatively harsh environments and working conditions. The gas sensing element within this equipment is perhaps the most fragile and crucial component, and if this was to fail, it would render the equipment useless. The selection of appropriate test gas is important to ensure the bump test is carried out correctly and as an active member of CoGDEM, Air Products know about it. They have contributed to the CoGDEM Guide to Gas Detection, a new hardback reference book which explains best practice and aids the selection of suitable test gases and equipment."

Leigh Greenham, Director, CoGDEM