re: Shop break in

Reminds me of a time back in the 80's. We were building oil and gas, pipe rack and equipment modules in a compound North of Saskatoon Saskatchewan in the middle of winter. -30 plus a strong wind blowing was pretty common that winter.  Anyway, a semi-truck making a delivery spun out on one of our electrical cords in the back 40 that was powering one of our headache shacks (lunch and foremen's trailer). Needless to say, it knocked out our furnace. I followed the damaged cord while packing a new one to plug in to an oil recycler building just over the fence that we had an agreement with to plug in that particular shack. The steel door was locked, so I just used a welding rod to release the simple door latch. Walked in and tripped over a binder twine strung 6" or so above the floor. Heard a clang and then hissing and then the strong smell of ammonia. Grabbed a breath and ran over and turned off the valve to a small ammonia tank. He had rigged the twine to a trip weight and a ball valve. Good thing it was daylight and I could see it. Would have worked great at night to keep the thieves out I guess!