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Gas Bottle Testing Facts - Gas Bottle Expiry: LPG Expiry Date

Gas Bottle Testing Facts - Gas Bottle Expiry - LPG Expiry Date

Gas bottle testing must be done every ten years because of the gas bottle expiry date. It is illegal to fill a gas bottle that is past its LPG expiry date but you are allowed to use it, past the gas bottle expiry date, if it still contains gas.

What is Gas Cylinder Testing (Gas Bottle Testing) & Gas Bottle Expiry Date

In summary:

• Gas bottle testing of gas bottles, cylinders and larger tanks must be done periodically for safety and re-certification.

• Gas bottle expiry periods vary, with 10 years being the most common for LPG expiry date.

• The gas cylinder testing date is permanently marked or stamped on the bottle.

• The gas bottles are subject to internal and external gas bottle testing for rust and any other damage.

• Physical gas bottle testing, including pressure tests, may be required depending on the type and size of vessel and the country where tested.

• The main valve is typically replaced when gas bottle testing takes place, for re-certification.

• A new gas bottle expiry date, of equivalent duration, is stamped into the neck ring after the new gas bottle testing.

• Only approved gas cylinder testing facilities are authorised to do gas bottle testing and re-certify gas bottles, cylinders and tanks after they reach their gas bottle expiry (LPG expiry date).

Gas Bottle Testing Procedures & Inspection: Step-by-Step Summary

The following is a step-by-step summary of gas cylinder testing and inspection:

  1. Determination that the gas bottle testing date has reached its LPG expiry date.

  2. External gas cylinder testing is performed.

  3. Cylinder is degassed to allow for internal gas cylinder testing.

  4. Old valve is removed and an internal gas bottle testing is done.

  5. The cylinder neck and valve threads are inspected for any damage as part of the gas cylinder testing procedures.

  6. A new gas bottle expiry date is stamped into the cylinder neck ring.

  7. A new valve is installed after successful completing of gas bottle testing.

  8. Any required refurbishment, including painting, is performed.

  9. The cylinder is ready for refilling and return to use.

  10. Any cylinders that failed the gas cylinder testing, at any point, are condemned and recycled.

Please note that if at any time a cylinder fails part of the gas cylinder testing procedure, they condemn the cylinder without bothering to do any further gas cylinder testing.

Continue reading to learn the details involved in each step…

Gas Bottle Expiry - LPG Expiry Date - How to Find the Date Stamp

Gas Bottle Expiry - LPG Expiry Date

Gas bottle expiry is the LPG expiry date for LPG bottles or cylinders.  Gas bottle expiry periods vary – with 10 to 15 years being typical.  When the gas bottle expiry is reached, the gas bottle can be used but cannot be refilled.

To determine the gas bottle expiry (LPG expiry date), you need to inspect the gas bottle's neck ring.

The cylinder manufacturer places the original inspection stamp on the neck ring at the time of manufacture.

For BBQ sized cylinders, the gas bottle testing and the stamp are valid for ten years prior to LPG expiry date.

After ten years, and any subsequent ten year periods, the gas cylinder testing must be redone.

The cylinder 'test station' will stamp a new inspection date into the neck ring, assuming that the cylinder passes the gas bottle testing.

So, it is always important to examine the entire neck ring to find all of the gas bottle testing dates that may be present, as it is impossible to remove the old stamps.

External Gas Bottle Testing

External Gas Bottle Testing - fire damage

The external surface of the gas bottle is inspected for defects, as defined by the applicable gas bottle testing Standard, AS 2337.1-2004. Failure in any one category of the gas bottle tesing is cause for condemning the gas bottle.

The kind of things they look for are swelling of the cylinder walls, the depth and diameter of any dents, the length and depth of any gouges, the depth and intensity of any corrosion, the presence of any cracks, or any damage from fire or heat.
The gas bottle in the picture was condemned for fire damage.

Gas Bottle Testing Preparation by De-gassing

degassing for gas bottle testing

At the start of the gas bottle testing process, the gas bottle is totally emptied of any remnant gas.  The old gas valve is then removed to facilitate the internal gas bottle testing.

A degassing station is shown in the picture to the right. 

Internal Gas Bottle Testing

LPG gas bottle with corroded cylinder neck area

Gas bottle testing includes an internal inspection.  Any gas bottle that fails to meet the gas bottle testing Standard is condemned.

A flexible scope, with illumination, is used to inspect the inside of the gas bottle. 
The interior is inspected for rust, scale, corrosion or any contamination. 
Normally, if the bottle has been kept either full of LPG or empty with the valve closed, internal rust and corrosion are not a problem.

Cylinder Neck

The neck of the gas bottle is a critical area of gas cylinder testing, as it is the point of attachment for the valve. Once again, failure in any area of gas bottle testing is cause for condemnation.

The valve threads are inspected to see if they are clean and intact, damage free, free of burrs and cracks or any other imperfections that could affect the integrity of the connection.

New Date Stamping of Gas Bottle Expiry - LPG Expiry Date

New Date Stamping of Gas Bottle Expiry - LPG Expiry Date

Gas bottles that pass all of the gas bottle testing are stamped with a new gas bottle expiry date, showing the month and last two digits of the year. 

In addition the test station stamps its own unique test station mark onto the gas bottle. 
Both stamps are typically applied in previously unmarked areas of the neck ring, as shown to the right.

Valve Installation After Successful Gas Bottle Testing

Valve Installation After Successful Gas Bottle Testing

After successful gas bottle testing, the next step is the installation of a new valve, as shown in the picture.  The old valves are discarded and recycled.


While not part of the formal gas cylinder testing process, the new valve installation should always be leak tested when refilled. 

In fact, this is the standard procedure for all subsequent refilling, as well.

Additional Swap Scheme Procedures 

Swap programs, such as SWAP'n'GO®, also refurbish the gas bottles after gas bottle testing but before they are refilled.


LPG gas bottles on an automated paint line

In addition to the normal gas bottle testing procedures, over half of the bottles tested by SWAP’n’GO would also be repainted.  Many would also be shot blasted prior to painting. 

The end result is a refurbished gas bottle in near new condition, with a new gas bottle expiry date stamp that is valid for ten more years. 

The picture shows gas bottles being repainted on an automated coating line.

Gas Bottle Recycling

Condemned gas bottels with large punctures for safe decommissioning

SWAP’n’GO bottles that fail gas bottle testing are condemned.

They are safely retired by punching a large hole in the side, so the metal recycling workers know that they have been safely decommissioned. 

In addition to recycling the steel from the gas bottles, the brass from the valves is also recycled.

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The information in this article is derived from various sources and is believed to be correct at the time of publication. However, the information may not be error free and may not be applicable in all circumstances.