This is what Chad Orzel refers to as a True Lab Story:
Condensed matter labs such as ours receive frequent deliveries of liquid nitrogen in one- or two-hundred liter dewars. Unfortunately, most of the Berkeley cond-mat labs are in Birge Hall, which has no loading dock, so that the LN2 dewars arrive on the first floor of neighboring LeConte where they must be wheeled over to their destination by some low-seniority student. Since the Berkeley campus is on a hill, the loading dock at the back of the building is one floor higher than the other entrances to LeConte and all the entrances to Birge. One can push the dewar around the outside of LeConte, but a shorter route is to take the elevator down one floor and go out the side door.
Yesterday the LeConte elevator was out of order, which for most of us would have meant taking the long way around. However, one undergrad, tasked with transporting a full 230L dewar, simply decided to take the stairs.
At about 80% the density of water, 230 liters of liquid nitrogen weighs about 400 pounds, not counting the additional weight of the steel vessel containing it. When rolled onto the stairs, the dewar promptly tipped over and plummeted downward on its side, knocking deep gouges in the marble steps and dragging along the unfortunate student, who inexplicably held on as his cargo began to tumble. Miraculously both student and dewar arrived at the landing without rupturing, but the dewar was still on its side and pressure was building up.
This was the situation when we got the frantic call from the building manager; once enough of us arrived at the scene we were able to pull the dewar upright and release the pressure. This averted any imminent explosion, but now we had a different problem: 400 pounds of liquid nitrogen stranded on a landing between the ground and first floors. Suggestions were floated including emptying the nitrogen out the nearby window, but ultimately we found another dewar which was wheeled to the top of the stairs on the first floor, and the nitrogen was transferred there through a long hose. The empty dewar was then carried up the stairs, a task requiring four men and gouging new (but shallower) grooves in the staircase.
Recalling what happens when a LN2 cylinder does rupture, it’s the general consensus that this student is lucky to have survived and LeConte Hall is lucky to still have a staircase.
Photos below the fold [updated with photo of wall damage]:
Here’s the staircase; note the bent and broken posts for the rail as well as the dents in the steps. The face shield was fortunately not needed. The white hose is being used to transfer nitrogen out of the dewar; it’s naturally more of a beige but it’s covered in frost.
This is the side of the steel dewar. It was not dented by the fall, but the white streak isn’t paint off the wall, it’s frost. Normally there is a vacuum space between the inner and outer walls of the dewar, but here the inner wall has apparently bent to touch the outer wall.
The dewar stranded on the landing. Here some nitrogen is being transferred into a much smaller flask, before the larger vessel arrived.
UPDATE: By request in the comments, here is a photo of the damage inflicted on the wall: