Jesus Christ, didn't they at least feel the drill go through when they punched the core. I would be wicked pissed.
A very similar situation. During the 3rd term of my IBEW construction and maintenance electrician;s apprenticeship, I was working on the total renovation of a local hospital. We were building 1 brand new 6 story plus basement wing from the bottom up, extending the length of an existing 3 story wing and adding two floors to its height. Simultaneously we were extending the length of another 3 story wing and adding two more story's plus an HVAC penthouse to its roof. Once we had most of the above work completed, we totally gutted the remaining original wing including floor slabs, supporting the original exterior walls and rebuilding the entire wing to 6 stories. This was approximately a three year project. I spent one term of my five term apprenticeship there, basically the last year of the project.
NOW TO THE SIMILAR PART:Four stories above finished grade, a core-drilling sub contractor was working his way across what had been the highest original slab in one of the original 3 story wings drilling holes through the slab for the fitting contractor to route various types of medical gas pipes through. Like any good core driller working in a semi dust sensitive environment he made a circular mound of sand around where he was drilling and poured about 1/4" of water on the slab. As his diamond core bit chewed its way into the core he added water to cool his bit, help clear debris and keep dust down in general. All had been going well, the sub-contractor had been working on this same elevation for several consecutive days. He was cutting one core when his puddle of water suddenly vanished. He added more water and it disappeared as fast as he poured it. Just like the fellow pouring diluted mortar (?) into holes for the glass pool surround, this fellow just kept on pouring water around his core bit.
In the U.S. I believe you jump from 3 phase 120 / 208 to 3 phase 277 / 480. Here in Canada our next common commercial voltage is 3 phase 347 / 600. In a small basement substation room supplying a wing of operating theaters above a wing of obstetrics / delivery rooms, the core-driller's debris laden water was gushing out of a 100 or 200 Amp 600 volt 3 phase fused disconnect switch feeding an operating suite IN OPERATION. In "operation" in more ways than one. As a 3rd year electrical apprentice I was about the lowest on the electrical totem pole of command and found myself in a pair of rubber boots above knee level with buckets of dry rags and instructed to open the live fused disconnect and keep it from shorting out until the operation in progress several slabs above was complete.
When I read of the core driller pouring copious quantities of diluted cement into his hole this experience from my apprenticeship leapt to mind.
Toodleoo!
Ron Hebbard.
