Ask the STAO Safety Committee: Gas Cylinders in Schools


gas cylinder

Question from teacher:

I currently have 4 gas cylinders in my science storage area. The gases they contain are hydrogen, oxygen, nitrogen, and carbon dioxide. They are currently individually belted to the cement wall, and attached with appropriate regulators. As there are 8 teachers in the department, the gases are used sporadically and at unpredictable intervals. As a result, the regulators are left in place during the school year. The oxygen, nitrogen, and carbon dioxide are adjacent to each other, while the hydrogen cylinder is isolated and 7 metres away from the other tanks. Is this arrangement appropriate chemical storage?

Response from STAO Safety Committee:  

To respond to your question, I consulted several government websites, and sent and received emails from appropriate regulators and suppliers of gas cylinders. I broke your general inquiry into 4 specific questions.  The answers to the questions summarized below are consistent with federal, provincial, and Ontario Fire Marshall regulations, and with the information found on Carrier websites (ex., BOC). Each source contained the same information.

1)    How should compressed gas cylinders be held in an upright position?   Always chain or securely restrain cylinders in an upright position to a wall, rack or other solid structure wherever they are stored, handled or used. Securing each cylinder individually is best. Use an insulated chain or non-conductive belt.

Source: http://www.ccohs.ca/oshanswers/safety_haz/welding/storage.html

Government website:  Canadian Centre for Health and Safety

2) What should the separation distance be for gas cylinders?

Store oxygen and fuel gases separately. Indoors, separate oxygen from fuel gas cylinders by at least 6 metres (20 feet), or by a wall at least 1.5 m (5 ft) high with a minimum half-hour fire resistance. (From: CSA W117.2-06 “Safety in welding, cutting and allied processes”. Local jurisdiction requirements may vary.) Compatible gases do not require a distance separation.

Source: http://www.ccohs.ca/oshanswers/safety_haz/welding/storage.html

Government website:  Canadian Centre for Health and Safety

3) When should regulators be removed?

Remove regulators when not in use and store these away from grease and oil. Put protective caps on the fittings when in storage.

Source: http://www.ccohs.ca/oshanswers/safety_haz/welding/storage.html

Government website:  Canadian Centre for Health and Safety

There does not seem to be any definitions or clarification that explain the frequency with which regulators should be removed. Each lab safety manual (and I looked at 10) suggests that this is done when transporting the cylinder, or bringing a cylinder to a mass storage area or when the cylinder is not going to be used for an extended period of time. For schools, this would likely be appropriate during the extended summer vacation when cleaning and maintenance staff may be in the storage area.

Every safety information source that I consulted indicated that when the regulators were removed, care had to be taken to ensure that they would remain free from dirt, corrosion,  grease, and oils. If the regulators were removed after each use, the likelihood of contamination, cross threading, leaking, and over tightening would increase. Further, the inconvenience of having to locate the regulator, install, collect the gas, and then remove the regulator would be great. I think that the safety concerns in constantly removing the regulators outweigh the safety gains significantly.

  • What does one local fire department indicate about the safe storage of gas cylinders in schools?

A  6 metre separation (for fuel and oxygen) would be adequate under the Ontario Fire Code. Typically in an educational laboratory setting, you would not have volumes large enough to have the requirements outlined in the Ontario Fire Code. You can secure inert and non-combustible gases adjacent to each other.

Source: Assistant Fire Chief, and Director of Fire Prevention

Your description of your gas cylinder storage is consistent with the requirements for pressurized gas cylinder storage that I have found at federal, provincial, and municipal levels. We hope that the information provided in this response will help you and your school board safety officer make an informed decision as to gas cylinder storage. If you discover any new information, please share that with the safety committee. If you have any other safety questions, please direct them to info@stao.org.  Please provide us with feedback as to the thoroughness and response time for this information that we have provided.

Dave Gervais

Chair of the STAO Safety Committee

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