Looking back on the Twin Towers in 1993

Posted on | September 11, 2011 | No Comments

In May of 1993, I was the managing editor of a trade publication devoted to, of all things, industrial pumping. In February of 1993, the original terrorist attack on the World Trade Center happened, via truck bomb. Repairing the buildings was a large undertaking at the time, and we learned of a pump vendor that provided a key component. I interviewed them and wrote a story about the project for the May 1993 issue of Pumps and Systems magazine. This is the text from that article. I’ll look to scan the original in and make a PDF available, as well, as there were a couple of photos that accompanied the article, along with a table of pump specs.

Section: Pumps in the News

Title: World Trade Center — Unique pumping solution speeds World Trade Center’s return to operation

On February 26th the New York World Trade Towers were heavily damaged by a bomb detonated in the center’s basement parking garage. The blast blew a crater approximately 150 feet in diameter from the second level of the garage (B-1) down to B-6. Tons of rubble created by the explosion came down on the core of the building services and cooling systems.

Among the emergency systems needed to reopen the towers was a cooling system to control the temperature in the 110-story twin towers’ elevator engine rooms. Without this system to prevent the machine rooms from heating up, the rising temperatures would stress the engines. “If room temperatures rise above 140 degrees F/40 C, problems would occur and the engines would cook,” said Rich Cullen of Hugh J. Cullen Associates, Neptune, NJ. “Once cooked, the engines would be there for life, as there is no way to remove them.” Of special concern was the possibility that April temperatures in New York City could rise above 70 degrees F, as they did in 1990 and 1991.

Contracts were awarded to supply and install a temporary system for climate control in the buildings, but it could not be up and running until the first week of May. Meanwhile, the New York Port Authority needed a system to get the center’s 260 elevators running safely on a “pre-temporary” basis so that the buildings’ 200+ tenants that had already moved back in could get back to business. Six different ideas were proposed by World Trade Center engineers for using existing mechanical and heating/ventilating/air conditioning systems to feed cool air to the rooms that house the 260 electro-mechanical elevator motors.

Gene Geyer, a sales representative for Cullen Associates Inc., noted “they expected to have several choices, but found they couldn’t tap into the domestic water supply lines. Those pipes couldn’t handle the extra capacity. So the only option the World Trade Center really had became available when the New York City Fire Department approved using the current fire protection standby pipe system.”

The standby system supplies water for fighting fires on the building’s upper levels. The presence of this system allowed for a parallel piped-in water cooling system with locking and interlocking valves that required little additional piping. The plan called for pumping water up the fire risers and tapping them off into the machine rooms, on floors B-6, 7, 41, 75 and 108. The fire pumps are manual pumps, and the new system is electronically interlocked with the fire system, so if the water is needed to fight a fire, the interlock automatically locks out the parallel system to give the fire department the water they need.

After settling on this plan, the Port Authority then requested bids for equipment on March 30, specifying a 10-day requirement for delivery. Cullen Associates was able to supply 650 hp worth of pumps and an automatic on-demand control system from Canariis Corp. within seven days. Details on the three-pump system, which is in place in both towers, are given in Table 1.

The temporary system scheduled to take over in May includes 10,000 tons worth of cooling towers and 35 chilled-water pumps capable of moving more than 100,000 gpm. This system was provided and installed by NuTemp Inc. of Chicago.

Emergency system start-up was scheduled for April 19. The emergency pumps, tied into the existing fire pumps, will remain as back-ups once the temporary chilled-water system is complete. On a long-term basis, the system will remain in place as a back-up to the fire pumping system.

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