Hamann says that if the building only relied on one set of pumps to overcome its massive height, then the initial amount of pressure needed would have to be around 640 psi. God forbid anything bad happens. At any given moment, two or three of the four pumps are running. Sensors throughout the building s pipes detect water demand by change in pressure values. For example, Hamann says that at around 5 p.m. when the offices start closing there is an increased use of water in the bathrooms.
Water pressure drops throughout the building.
The pumps detect this drop in pressure and speed up to compensate. Back to Main Water flows easily at Windows on the World, a bar atop the World Trade Center, despite traveling more than 1,300 feet up. World Trade Center Facts - 200,000 people visit the World Trade Center everyday. Tower One, at 1,358 feet, is four feet shorter than Tower Two. Bob Hamann, general maintenance supervisor at the World Trade Center, shows the pumps that move the Towers' water.