Installation of Studor Air Admittance Valves (AAVs) by Plumb-Tech Design & Consulting Services LLC and Hulsey Engineering avoided the problem of sewer gases entering the Ford Field Stadium (home of the Detroit Lions NFL football team) from the rooftop Air Handling Units (AHUs) which were situated above the concourses. They also made a saving of over $¼ million on installation costs*!
The construction of the stadium was completed in August 2002. The complex, comprising 1,830,000² feet, included the renovation of an existing 9 storey warehouse building which was incorporated into the site plan and used as one wall of the stadium
Spaces in the warehouse were provided for offices, a hotel, restaurants, retail and other outlets for letting. The concourse level went through two floors of the warehouse and there was an additional private club level.
The warehouse building includes 132 suites, each with a private bathroom, plus 30 public restrooms on the lower concourse level and 23 on the upper concourse level. The stadium has over 906public water closets, 363 urinals, 625 lavatories, 47 mop sinks and 60 showers. There are 25 food concessions on the lower concourse level and 21 concessions on the upper level.
The stadium has a seating capacity for 65,000 seats with the capability to expand to 70,000 if required.
1. In many areas of the stadium, there were rows of rooftop AHUs providing cooling and make-up air to the stadium. Vents installed in these concourse roof areas could result in sewer gasses being drawn into the make-up AHU intake hoods and distributed by the AHUs into the stadium.
2. Installing conventional vents through the roof would have been extremely difficult: Significant additional piping would have been necessary to re-route away from the AHU intake hoods. Alternatively, the vents could have been routed to the upper stadium roof, but this location was significantly higher, more difficult to reach (and therefore more dangerous) for installation.
As AAVs work by opening to admit fresh air only when it is needed (at the Point of Need), and close and seal tight by gravity when the need has passed, their use on the roof vents prevented the sewer gases from being drawn into the stadium through the AHU make-up air hoods.
Approximately 152 Studor Maxi-Vent and 140 Mini-Vent AAVs were installed throughout the complex, including the plumbing chases in the majority of restrooms and concessions around the main seating bowl.
At the time the stadium was constructed (prior to the launch of the Studor P.A.P.A.), it was found that in some locations conventional venting was still necessary to relieve positive pressures that could potentially occur, especially if there were high peak demands during the halftime break of sold out events. The conventional vents were located at strategic restrooms and lower concourse manholes to keep the drains within the pressure limitations required.
When the Ford Field Stadium was built AAVs were available as an alternative engineered system. Implementing them within the development of the complex allowed the freedom for the preferred design, whilst minimising the risks of working at height, as well as maintaining the quality of the indoor air quality and providing a high performance drainage ventilation system.
At the time it was acknowledged that there were cost savings due to the reduced material and labour, but these were not quantified as they were not the major consideration. A subsequent cost analysis, commissioned in June 2011, compared the cost of installing a conventional cast iron vent piping system versus installing AAVs for each public restroom and the vent up through the stadium to the roof level. This comparison showed that the cost of material and labour by using Studor AAVs was more than $¼ million less than conventional venting methods.
*Saving calculated by the cost comparison report prepared by Plumb-Tech Design & Consulting Services LLC and Hulsey Engineering in June 2011.<< back
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