Vac to the Future: A New Waste Plumbing System At the NewYork-Presbyterian David H. Koch Center

The NewYork-Presbyterian Alexandra Cohen Hospital for Women and Newborns, scheduled to open in summer 2020, features advanced medical technologies and equipment. The same can be said of its waste system – the first of its kind to be used in a New York City hospital.

The system in question is vacuum waste plumbing.  We chose this option to address an unusual challenge that we faced as plumbing engineers.  Because the hospital occupies the top five floors of the NewYork-Presbyterian David H. Koch Center, we had to ensure that its construction did not disrupt activities on the floor below, which contains the Main electrical service and emergency generating plant for both the DHK building and womens hospital.  That meant we couldn’t use traditional gravity sanitary drainage piping.

After analizing several options To resolve the problem, we as a team (NYP and SHG) determined a vacuum waste system would best suit the problem. After researching vacuum sanitary systems and visiting facilities with vacuum systems we settled on Acornvac as The basis of design.

What is a vacuum plumbing system?

Vacuum plumbing systems use continuous vacuums to transport wastewater through an engineered drainage piping network before discharging to traditional gravity sanitary waste system.  The interface of atmospheric pressure at the toilet bowl and a constant vacuum pressure in the waste piping network provides a highly efficient flush, using only ½ gallon of water. When the push button is activated, the extraction valve opens, allowing atmospheric pressure to push toilet waste into the vacuum piping, after which the waste is ground into fine particles, before entering the vacuum center. A water valve is simultaneously activated, allowing the toilet to be rinsed and refilled.

The vacuum center includes vacuum pumps, waste collection tanks and controls that automate the operation of the system. Waste is delivered from fixtures and equipment to the vacuum center waste collection tanks via the vacuum piping network, where it is temporarily held before discharge to gravity sanitary sewer mains.

Although the system varies considerably from gravity drainage plumbing, the appearance of toilets and sinks used in both systems is similar.  Users perceive no difference.


For us, the primary consideration was avoiding disruption on the floor below and a possible catastrophic leak in the main electrical service and emergency generating plant , but there are many other benefits associated with vacuum waste systems, including:

  • Improved hygiene through the containment of wastewater, prevention of piping leaks, and elimination of water vaporization during flushes
  • Less maintenance: reduction in main line blockages
  • Flexibility: The vacuum waste piping network is typically smaller in diameter than traditional vent piping, and it can be installed horizontally or vertically because it does not require continuous slope.
  • Energy efficiency: The toilet uses 0.5 gallon of water per flush. The traditional toilet flushometer is 1.28 gpf.

In Europe, such systems have been used for several decades, but they are relatively new to the U.S. market. So far, they are popular choices among department stores and prison facilities, but they are gaining traction in the medical field. At this time, we are considering these systems for several projects in design.

Click on this video to see an AcornVac in action. And don’t hesitate to contact one of us if you have any questions or wish to learn more. You can reach us at and


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