A Thought For Today,

have you ever thought about liquid nitrogen tanks?

no I guessed not, neither had I until I read this engineers report, in the past history of this tank both the pressure relief and rupture disks had failed for some reason in the past, so accidents like an increase in pressure due to say rising temperatures have have been known to occur, true in this one both disks had failed for some reason in the past, so they'd been removed and sealed off with metal plugs, the point is they still failed, the engineers report,

'the cylinder had been standing at one end of a ~20' x 40' laboratory on the second floor of the chemistry building. It was on a tile covered 4-6" thick concrete floor, directly over a reinforced concrete beam. The explosion blew all of the tile off of the floor for a 5' radius around the tank turning the tile into quarter sized pieces of shrapnel that embedded themselves in the walls and doors of the lab. The blast cracked the floor but due to the presence of the supporting beam, which shattered, the floor held. Since the floor held the force of the explosion was directed upward and propelled the cylinder, sans bottom, through the concrete ceiling of the lab into the mechanical room above. It struck two 3 inch water mains and drove them and the electrical wiring above them into the concrete roof of the building, cracking it. The cylinder came to rest on the third floor leaving a neat 20" diameter hole in its wake. The entrance door and wall of the lab were blown out into the hallway, all of the remaining walls of the lab were blown 4-8" off of their foundations. All of the windows, save one that was open, were blown out into the courtyard',

thank goodness no one was in the lab at the time, but here is a thought, if you live in New York many of you will walk past one or two of these cylinders every day, 

they are allegedly, according to this article placed on the sidewalks by Verizon, a telephone company and they confirmed that some of the nitrogen tanks are theirs and are there to help keep moisture out of telephone cables, they also noted that they are completely safe, saying "if a tank was punctured, nitrogen would dissipate in the air without harming anyone around it, or the environment." well that is a relief, but I still think I would cross the road on a hot summers day to avoid walking by one, just in case.