Updated: Dec 2, 2020
As dangerous goods consultants we see a lot of common mistakes when storing liquefied petroleum gas (LPG) in exchange cages. In this article we look at impact protection for LPG exchange cages.
This article is general information only. Want expert advice, specific to your needs: get in touch.
Two bollards, a glass door, a steel cage. Click the image to watch the video.
Exchange Cages are typically intended to be accessed regularly and on sites which are open to the general public. This usually means putting them somewhere visible so that customers know that it is part of your offer. Unfortunately that also exposes the cage to the many vehicles being driven onsite. As shown in the video above, impact from a vehicle can damage the cylinders creating a leak of the flammable LPG.
The above example is a very severe case which would be very unlikely to occur, however more likely impact scenarios could occur with cages located near:
parking areas where cars are being reversed
site entrances where cars are slowing down to enter off the main highway
the end of a terminating vehicle pathway where cars have to turn to avoid the cage
There is also a legal requirement for impact protection for dangerous goods storage in WA as per regulation 54 of the Dangerous Goods Safety (Storage and Handling of Non-Explosives) Regulations:
"An operator of a dangerous goods site must take all reasonably practicable measures to ensure that the dangerous goods and any storage or handling system at the site is protected against damage from impact."
To determine what level of impact protection is acceptable for your exchange cage, you need to consider the following:
vehicle movements around the cage - the frequency, speed and typical pathway followed
traffic calming measures - e.g. speed bumps, sharp turns, speed signs
physical obstructions - e.g. kerbing, bollards, crash barriers, fencing
The typical exchange cages are designed to withstand low energy impact, as are the cylinders themselves. Check out this interesting practical experiment conducted in Texas. This means that in an area with vehicles travelling infrequently at a low speed, the cage itself may be sufficient impact protection. It is important to note that ideally the energy from the impact should be absorbed by the cage sliding along the ground rather than damage to the cage itself. So make sure your cage is able to move along the ground in the direction it is likely to be hit from.
If your cages are located in an area where they are exposed to high energy impacts, such as vehicles moving directly towards them from a main roadway, consider a combination of:
relocation to a better protected location
installation traffic calming devices to change the direction and/or speed of the traffic
installation of bollards or crash barriers which are sized based on the size and speed of the vehicles entering the site.
AS/NZS 1596 The storage and handling of LP Gas Appendix Q provides a good risk assessment tool for impact protection. It also includes generic designs for some of the common impact protection types.
Did you have any of these issues on your site? Hopefully this article helped you provide adequate impact protection for your LPG cylinders. If you found that useful, check out some of the other common mistakes with LPG Exchange Cages:
If you have other dangerous goods storage onsite, we also have articles on some other dangerous goods storage types.
Although these are some common mistakes, remember there are a whole heap of other compliance and safety issues associated with LPG exchange cages. Make sure you check your DG risk assessment and get in touch if you have any questions!
This article was prepared as general guidance only and based on information current at time of publication. The use of this information is at the reader's own risk, Cadre Engineering accepts no liability for any outcomes of following this guidance. For expert advice, specific to your needs, please get in touch.