As a non-engineer, I’ve always been awestruck by big projects. Watching the construction of highway ramps, I try to imagine the plans that determine where to dig or fill, and how all that information is passed along to the equipment operators who actually move the dirt. I’m filled with respect for the minds that create the plans: the math and technology involved are way over my head. But other than little boys, construction workers and engineers, most of us drive by those projects without a thought.
What a loss — we pass up so many opportunities to be amazed.
McCord Hall is smaller scale than a highway intersection, but it too is a marvel of planning. When we move in, however, most of us will enjoy the fruits without considering how it all happened. Tom Corey, who supervises the various subcontractors working in McCord Hall, took these pictures.
Looking up …
For example, in various parts of the building there might be a lot more over your head than ceiling tiles, lights and sprinklers. This photo, taken in the basement, shows water and waste pipes. In most areas of McCord Hall these are not overhead, and of course this is drawn into those detailed plans. But as buildings become real in concrete and steel, issues that were not foreseen when the plans were drawn come to the fore, and there are decision points. For example, the plans might show a pipe crossing a beam, or several systems might need to run through the building at the same ‘elevation.’
DPR used a BIM (Building Information Management) system to coordinate the installation of these systems. BIM is a software program that generates a 3D model. Every Thursday morning while the systems were being built, the subcontractors walked through the building virtually and identified problems in advance — like the places where pipes and ducts crossed or a beam obstructed access. In one case, the electrical conduit had to be moved to accommodate a staircase, and throughout the building where systems shared the headroom, BIM allowed the contractors to plan how they would stack up.
Above everything is the roof. DPR, the architects and ASU are currently working on a plan to screen the air handlers from our view, but in fact, most of us would probably have not noticed the big box.
ASU air conditions our buildings using chilled water that is refrigerated to a low temperature in the central plant nearby, stored in tanks beneath the SRC fields, then delivered to air handlers in gleaming pipes like these.
Back inside the building, the floor below your feet is no more dead space than the area above the ceiling tiles.
If you had toured McCord Hall earlier in the project, you would have had to jump down to get from the doorways to the interior spaces. That’s because the floors are about two feet above the concrete slab, leaving room for the cable trays and conduits that carry data lines and electricity and the air distribution balancing ducts that deliver chilled air to the rooms.
This sub-floor chamber is called a plenum – a new word for me that I learned by Googling it during a construction meeting. McCord Hall will use and underfloor displaced air system that will supply a low velocity, low pressure supply of air to the spaces in the building. The plenum is sealed air-tight to keep dust away from these systems: it will be cleaned three to four times before we occupy the building to assure that no construction dust found its way into the space.
… Looking all around
… and this is what the wiring looks like inside the walls of what will become a team room. Here as everywhere else, the details matter – like where a light switch is placed. I was curious about the reason for mounting the fire alarm switch higher than the light switches, but apparently that’s a matter of code.
The day we visited, workers were installing sheet rock, but before they could start, a series of inspectors examined the wiring and cabling. After the ASU and Tempe inspectors sign off, DPR comes through for a “zero defect” inspection, when the plans are double-checked to be sure that what was designed actually got built.
The sheet rocking is an example of crew efficiency. The area is divided into three zones and the crews move through them in sequence. First the dry wall crew does the “one siding,” which means they hang drywall on just one side of the walls then move on to the next zone. The second wave of workers install insulation, the third hang the second wall, finishing the sandwich.
Next we’ll take a look at the ways the indoor environment at McCord Hall differs from any other building on campus.