Concrete Plumbing Solution

Plumbing engineers play a key role in creating the optimal conditions for medical research

By Tom Boehnen, P.E., Director of Plumbing Engineering, Arnold & O'Sheridan, Madison, Wis. April 1, 2002

A bastion for those with developmental disabilities, the Waisman Center, on the campus of the University of Wisconsin-Madison, has not only been a clinical resource for people with disabilities and their families, but the focal point for multidisciplinary research on the matter for almost 30 years. In fact, it is one of only seven regional centers in the United States for such research. To meet its growing needs, center officials recently added a seven-story tower to the building. A behind-the-scenes, but significant aspect of this expansion involved the plumbing systems, which were integrated early into the overall design.

To understand the tower’s special plumbing requirements, a brief examination of the addition itself is in order.

To call the tower a multi-use facility is an understatement. The first floor alone houses a magnetic resonance imaging scanner, a positron emission tomography scanner and a linear accelerator. The second floor supports lecture halls, administrative services, an auditorium and the main mechanical equipment room. The latter also occupy what would be the third floor. The Clinical Biomanufacturing Facility, where products for clinical phase-one trials are made, constitutes the fourth floor. This particular facility also hosts the current Good Manufacturing Practice (cGMP) labs, as defined by the U.S. Food and Drug Administration. The fifth and sixth floors include bench laboratories and support spaces, including researcher offices as well as warm and cold rooms. Holistic approach

These multi-faceted functions necessitated a complete, multidisciplinary design. And despite the fact that each floor has an almost completely different use—and therefore required completely different plumbing and electrical services—the systems serving each floor needed to be integrated. In fact, designers could not afford to work just one floor at a time. Rather, the interrelation of all functions and spaces had to be at the forefront of their planning.

With this in mind, a concrete-joist system was conceived via collaboration with the architect—Bowen, Williamson and Zimmerman, Madison—and the structural engineer—SRI Design, Madison—to maximize integration of the horizontal plumbing distribution.

This approach was necessary to reach the various lab locations without compromising valuable ceiling or floor space. Branch plumbing drain lines were also installed in the concrete joist depth to further this goal.

Starting on the first floor, the plumbing and piping systems, specifically, are distributed through trenches, access flooring and suspended ceiling spaces. Throughout the rest of the tower, these systems are designed with vertical risers and distributed horizontally above suspended ceilings. Plumbing stacks are located along permanent vertical elements such as columns and elevators, so that if internal functions change, the stacks won’t need to move. Piping Preview

The plumbing and piping systems, themselves, include domestic hot and cold water, purified water, specialty gases—including argon, oxygen, nitrogen and carbon dioxide. The cGMP lab needed additional services, such as nuclear injectables, vacuum systems and steam piping.

These specialized systems are designed with a central vertical riser in a shaft near the elevator. Collector mains and stacks for chemical drain lines are purposely located on the outside walls at columns. The structural design accommodates these stack locations by connecting the concrete joists on the side of the columns. This arrangement leaves a space at the column face, through which the stacks are sleeved through the floor.

The horizontal mains on each floor are located in a single, conveniently-located main corridor that supplies all the building services to the various labs. In these corridors, the location of plumbing pipes had to be closely coordinated with the transmission mediums of other services, including ductwork, electrical conduits, structure ceiling sprinklers and telecommunications/data cabling. To coordinate this distribution, strut type hangers were provided by the mechanical disciplines to supports all piping and conduit.

The tower expansion also boasts a wastewater-treatment plant. Specifically, a dilution basin pretreats wastewater so as not to discharge it into the city sewer system with a high acidic or alkaline content.

The gas and vacuum systems, like the other piping systems, are run through vertical risers and distributed horizontally through the services corridor before branching out to the laboratories. Furthermore, the domestic water supply was purposely separated from the purified water system—installed for use in the research labs—because the latter has no chlorine to combat bacteria. Instead, purified water is constantly circulated. The 10-megaohm-quality water is generated using a reverse-osmosis filter, with final polishing done via mixed-bed deionization cylinders in the circulation loop. The purifying equipment is located in the second floor mechanical room.

Another consideration affecting the purified water system was that the cGMP facility required an additional level of quality to meet U.S. Food and Drug Administration guidelines. This was problematic because maintaining this grade of water, at the necessary quantity, would be costly. Instead, it was recommended that the cGMP facility simply purchase bottled water.

Another piping system of note is the central vacuum system, used to control the atmospheric conditions surrounding experiments and also to dry out equipment. Central pumps produce 20 in. of mercury vacuum, or 255 Torr. These pumps are located in the second floor mechanical room with piping distributed vertically to each level—along with the other main risers—and horizontally to the individual lab spaces.

The vacuum system for the cGMP suite features a separate main, which has to be filtered with HEPA-quality elements before it can connect to the vacuum pumps.

Meanwhile, the specialty gas piping design utilizes local gas manifolds on each floor, with gas piped into each different research laboratories according to need. Copper piping worked well for most labs, excepting the fifth and sixth floors, which required stainless steel to accommodate possible future changes in specialty gas needs.

Drain piping also required special attention. In the individual research labs, each table has water and gas connections, fume hoods, eyewash fountains and emergency showers, as well as chemical resistant drain and vent piping to both sink and floor drains. In some cases, special plastic drains were used for pure water waste. Flexibile and farsighted

During the nearly 30 years that the Waisman Center has been operating, there have been many changes in the research being done—along with the building systems necessary to support that effort. As a result, accommodating future developments was an important consideration in designing the new addition.

Take the fifth and sixth floors, which house both bench labs and office space, for example. The plumbing systems are integrated so that very simple branch connections can be made to convert office space if more lab space is needed. Additionally, chemical drain piping can be added in the joist space of the floors below without interfering with ductwork.

Such farsighted design enhances the capabilities of this important facility—a requisite—as the plumbing network literally serves as the arteries of this building’s sophisticated systems, which are, of course at the core of both the structure and its mission.