Monday Accident and Lessons Learned: Don’t Collapse Your Tank!
Wil Ferch, a reader of this site, sent this posting to help people prevent a repeat of past accidents. Knowledge of past problems may help you prevent them in the future!
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Don’t let this happen to you !!
The industrial gas industry, (producers of liquid oxygen, nitrogen and argon…amongst other products of air), require large site-erected tanks to be built in order to store these liquids for later use. These tanks can range in size up to 2 million gallons or more, and cost millions of dollars. The stored product, like liquid oxygen, exists at about minus 300 degrees Fahrenheit. This situation and concept applies equally to other cryogenic processes, such as LNG stored at approx minus 260 degF, etc.
In the process of bringing such a newly constructed tank into service, it must first be carefully “cooled-down” such that it can accept incoming cold liquid later.
Nordstern Associates LLC – CASE STUDY # 7
A major global producer of industrial gases, recently “cooled-down” such a tank, utilizing their own qualified personnel and historical procedures. This time, however, things went horribly wrong, and their 450,000 gallon, liquid-oxygen tank went from being a multi-million dollar asset to nearly scrap metal value, in a fraction of a second ! In the process of cooling down the tank, it vacuum collapsed ! To illustrate the violence, sudden-ness and uncontrolled nature of the collapse, here is a YouTube film clip showing a similar (this time, on purpose !) tank collapse of a railway tanker.—> http://www.liveleak.com/view?i=72e_1208694365&p=1
Also, when a field-erected, flat-bottom tank vacuum collapses, it may implode the top and side walls, and also start to “lift” the center of the flat floor. See here of what such damage looks like in yet another example (scroll down to the title,…. “Plastic Bag vs. Storage tank”)—-> [Note from Editor: this link removed due to virus report] and click on each photo for an enlargement.
After the damaged oxygen tank was repaired, Wil Ferch of Nordstern Associates LLC was enlisted to provide both a revised cooldown procedure and on-site supervision of the new attempt to cool-down the tank. Result? A perfect cool-down with no damage!
So….don’t let this happen to you!