Design Horror Stories, Part 2

By Timothy Allinson, P.E.

Murray Company, Long Beach, Calif.

You may recall, faithful reader, that a year ago, in the October '05 issue, under the guise of the Halloween theme, I wrote about design horror stories. I got through only about half of the more dramatic stories I could remember, so I promised that they would be continued in the October '06 issue. For the sake of keeping that promise, and in case anyone out there actually learns by reading about my experiences, here is the balance of the more dramatic stories I have accrued in the past 21 years.

The high-rise office building
As a young engineer, this was one of the first projects for which I was given a broad range of design responsibility. Unfortunately, it turned out to be a project riddled with problems. These were not typical design errors, but strange, unique problems, impossible to predict.
The building was a 46-story office building in Times Square, Manhattan. The design, bid and construction went off without a hitch - that is, until shortly before completion. (Dim the lights now, and put on scary music.)

As the base building was under construction we were contracted to design the fit-out of a major office tenant who occupied floors 17 through 27 and the sub-basement, the lowest floor of the building. As this tenant fit-out was under construction, an odd thing happened: many of the floor-to-ceiling double-pane window panels were found cracked - on the inside pane only. A total of 180 panels were cracked and had to be replaced. This was obviously the work of a disgruntled employee, either of the general contractor or of one of the subs. The panels were replaced in short order, but the mystery persisted.

Shortly after the window debacle, the fire department received a call about a rooftop fire at the building - one that had been set at the end of the day with a long fuse to create a blaze in the middle of the night.

One of the unique requirements of NYC construction back then was the installation of what was referred to as a temporary fire standpipe, one of the permanent standpipes that was installed early and had a dedicated fire department connection, in case firefighters should have to fight a construction-related fire such as the aforementioned rooftop blaze.

The trouble with a temporary fire standpipe is that it is dry, so there is no way of knowing whether the firehose valves are open or closed. The fire department showed up to put out the rooftop fire, and the firefighter on the roof, with a hose connected to the temporary standpipe, kept calling for more water, not knowing that most of the water being pumped from below was cascading throughout the building via hose valves that had been left in the open position all the way up the standpipe.

I doubt that the arsonist that lit the rooftop fire had the foresight to open all the FSP hose valves, but you never know. The end result was that the tenant on floors 17 - 27, where construction was complete, and office furniture was lying on the carpeted floor awaiting assembly, where the sub-basement was fitted-out and ready for occupancy, was devastated by the water damage. Not to mention that the elevators and other infrastructural elements were destroyed by the fire-fighting flood.

Although this was not a design issue, the lesson learned was that, in order to reduce the potential of a fire-related flood, hose valves on dry fire standpipes must be monitored to be sure that they are closed during the construction process. This is particularly important in a high-rise building.

The final irony on this project consisted of a unique design quagmire. The domestic water pumps had been selected and scheduled with a pump head of 695 feet. On Day One, when the pumps were put into service, the water did not quite reach the roof tank the pumps were intended to fill.

Informed of the news, we started researching how this could be possible. After an exhaustive review, we discovered that the pump head of 695 feet had been read and drafted (back in the hand drafting days) as 645 feet. Thus, the pumps were short 50 feet of dynamic head, an easy mistake, easily missed. Fortunately, the pumps were vertical turbine pumps to which a stage could be added without increasing the power requirements of the pumps and at no cost, courtesy of an allegiant manufacturer's representative. So, what could have been a major design problem turned out to be only a minor inconvenience.

Another high-rise office building
The horror stories associated with this NYC project are brief and had nothing to do with the plumbing design, but they are interesting just the same.

As the structure of this building neared completion, a series of criminal events ensued. It seems that a disgruntled contractor had decided to throw things from the building onto the streets below. First was a large structural bolt that came dangerously close to hitting an unsuspecting pedestrian on the noggin. Second was a pair of vice-grips that pierced the roof of a taxicab and broke its passenger's shoulder.

Fortunately, none of the psychotic events ended in tragedy, but they easily could have. The general contractor was very proactive and hired a psychological profiler to interview all of the tradesmen in an effort to find the culprit, which proved to no avail. Who knows, it could have been the same psycho who broke the windows of the building referenced above. After all, the two projects were just down the street from one another. The natures of the crimes, however, were very different - the former being very calculated, while the latter was spontaneously malicious.

Low-rise office park
This Florida office building was another project designed early in my career. Our scope included complete M-E-P-FP design. Having designed the fire sprinkler system, I was given the responsibility of reviewing the fire sprinkler shop drawings. This is where things went awry.

The sprinkler contractor had indicated all of his piping elevations, which I reviewed to be sure they weren't in conflict with light fixtures. One parameter of the project was that all four floors of the building had a six-inch raised floor for computer cabling, which both the contractor and I had forgotten about when determining the sprinkler piping elevations. As a result, all of the sprinkler piping was installed six inches too low and had to be raised - quite a project! Ultimately, it was the contractor's problem to resolve, but it would have been great if I had picked up on the error and spared the FP sub a huge amount of additional work.

Hospital utilities
This project consisted of the relocation of major utilities serving an existing Los Angeles hospital in order to allow the demolition of an adjacent building to make room for a new patient tower. The new utilities had to run through the hospital and into the street to reconnect with existing utilities several hundred feet away. Three unpredictable things occurred to make this project much more complicated and expensive than expected.

First, shortly after the utility trench had been excavated along a major thoroughfare, the trench unexpectedly collapsed. I don't know the details as to why it collapsed, but, fortunately, nobody was hurt. After the trench collapsed, it had to be filled with slurry and re-excavated, which, as you can imagine, was quite a chore.

Second, as the excavation continued, the digger hit an abandoned electrical conduit bank, 4 feet by 4 feet, encased in concrete. Fortunately, the conduit was inactive, so it could be removed, but that just further hampered the underground work.

Third, the excavator hit a fire service line with press-fit joints, making excavation around the thrust blocks even more difficult than expected. These buried treasures caused severe cost over-runs, most of which we were able to recoup.

Pump fiasco
The owner of a high-rise office building here in Orange County called me to investigate some severe pressure fluctuations in the building. The source of the pressure fluctuations, which were on the suction side of the pumps, was impossible to determine. There was surely a blockage in the suction line somewhere along its 200-foot length, buried under concrete, but it could not be found. The existing domestic water pumps, which had been retrofitted with Variable Frequency Drives (VFDs), were old and not performing well. I mentioned the situation to a pump manufacturer specializing in custom VFD set-ups, and he assured me that his VFD system could smooth out the fluctuations. He even guaranteed this in writing.

Well, we bought the pumps and installed them; however, they failed to smooth out the suction pressure fluctuations. They did a better job of it than the original pumps, but they were also prone to failure. The pumps had to be pulled out several times and shipped back to the factory for repair. Ultimately, the owner lost confidence in the pumps and wanted them taken out. The manufacturer took back the pumps, but we lost a great deal of money in labor pulling the pumps out and resetting them - on overtime, no less.

We decided to replace the pumps with more traditional VFD sets, and we also made some changes to the water supply. Unfortunately, as the new pumps were being installed, via a crane through a large areaway, the rigging slipped and the pumps fell 12 feet onto the concrete below. This, as you can imagine, is not good for pumps. They had to be sent back to the manufacturer for $12,000 in repairs - out of our pocket, of course.

Eventually, we installed the repaired pumps and made the water supply changes; since then the systems have been working fine. Unfortunately, this served as another example of a simple project gone awry.

Hospital tanks
One day I got a phone call from a structural engineer I'm friendly with. He needed a little forensic engineering and asked me to meet him at a large new hospital in Los Angeles. I was familiar with the site.

I got to the building and couldn't believe my eyes. Immediately adjacent to the main entry was a large buried water storage tank, approximately 60 feet by 40 feet, which had entirely collapsed. The crater looked like the aftermath of a missile strike.

My structural engineer friend looked at me and said, "I've done the calculations: It was structurally sound - for surface loading anyway." We talked a bit and quickly came to the obvious conclusion that the tank could only have failed due to hydrostatic pressure from the inside.

The tank was designed structurally for a surface loading of about 720 pounds per square foot (psf), which translates to about 5 pounds per square inch (psi). This is also the design threshold for upward pressure on the underside of the lid. With 5 psi of surface loading, if the internal pressure of the tank reached 5 psi it would be in a neutral state. If the internal pressure reached 10 psi it would create a 5-psi net positive pressure on the lid, and it would be subject to failure.

A survey of the tank fill system inside the building, coupled with a chat with the building engineer, confirmed our theory. It seems that when the tank was first filled it was filled manually. With the fill switch in the "hand" position, the operator had no way of knowing how full the tank was. Since the tank did not have an overflow system, merely a small vent, it did not take long, once the tank was full, for the six-inch water supply to overwhelm the vent line (which served unintentionally as an undersized overflow) and produce positive pressure inside the tank. Kaboom! The enormous lid collapsed. This failure punctuates the importance of safety controls and overflows when designing such a system.

Several weeks later, I got a call from another engineer doing work for the same hospital. It seems that he had been contracted to determine the source of horrible odors that were emanating from the site. A brief discussion revealed that the hospital had a sanitary holding tank incorporated into the main drainage line. The design was simple - too simple. The main sanitary drain passed through a room the size of an auditorium before exiting the site to the street sewer.

The design intent was to create a sewer storage volume in the event that an earthquake rendered the street sewers inoperable. The practical result was a large subterranean room that got clogged with solid waste from insufficient flow velocity, producing an extremely undesirable and unsanitary condition.

I never learned the aftermath of this fouled sewer system design, but I imagine it was rolled into the same lawsuit associated with the water storage tank. Both of these examples prove that a plumbing system improperly engineered can be a dangerous thing.

Jakarta
The last design horror story I would like to share has to do with a project I designed in Jakarta, Indonesia. No aspect of this horror story has to do with plumbing specifically, but with the methods of construction considered standard in that part of the world.

No place, I believe, is more bizarre than Jakarta when it comes to the contrast in degrees of wealth. The meetings that were held for this project were in a marble-clad office building with finish levels I have never before seen in the United States. Immediately next door was a corrugated metal shack that probably housed a family of twelve. The contrast was staggering.

As construction began it was immediately obvious that the crews worked around the clock - there is no such thing as overtime in Jakarta. After dinner, having spent collectively more than the average Indonesian family would earn in a year, we walked past the site. Construction was in full bloom; there were, however, several painful differences between this construction site and those in the United States.

Each construction worker was issued work boots and a hard hat, but both were quickly sold to purchase the commodities they needed to survive. Hence, all of the laborers on site wore nothing more than shorts and tee shirts.

As we watched the excavation of the hole we had designed, beams of light danced across the site from the excavators. Even more surreal were the dump trucks with their bald tires that had to be pushed up the dirt slope by the scoop of the excavators, as men clad in nothing but shorts and tee shirts rode atop the dirt pile.

As we left the site, each of us was thankful to be an American living in the USA rather than Jakarta. We truly are blessed in this country, and you need not travel far to be reminded of that fact.

Happy Halloween
I hope you have found these horror stories entertaining and potentially useful. Enjoy the ASPE Convention, if you are going, and have a very happy Halloween.

 

Timothy Allinson is a Senior Professional Engineer with Murray Company, Mechanical Contractors, in Long Beach, Calif. Prior to entering the design-build industry he worked for Popov Engineers, Inc. in Irvine, Calif, and JB&B in New York City. Tim holds a BSME from Tufts University and an MBA from New York University. He is a professional engineer licensed in both mechanical and fire protection engineering in various states, and is a leed Accredited Professional. Tim is a past-president of ASPE, both the New York and Orange County Chapters, and sits on the board of the Society of American Military Engineers, Orange County Post.