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WHITE PAPER

Storm Drainage System Research Project

It was brought to the attention of the American Society of Plumbing Engineers Research Foundation (ASPE RF) that a number of failures with storm drainage systems had occur red. The types of failures included:

  • Collapse of roof
  • Pipe fitting separating
  • Hanger pulled from prestressed concrete floor/ceiling
  • Flooding of upper-level balcony decks
  • Fitting component failure
  • Flooding in the building on upper floors due to pipe failure

Many of these failures resulted in litigation. Of the litigation failures directly identified to ASPE RF, all of the cases were settled. Because of the settlements, the specific cases cannot be identified.

Two of the cases involved testing at SGS U.S. Testing Company (now known as OAI Laboratories Ltd.) in Tulsa, Oklahoma. A mock-up roof assembly was created to test the flow rate through various roof drains. In one set of tests, a 10-inch roof drain was tested to determine the flow rate based on the head height of water ponding around the drain. (ASME A112.6.4 regulates roof drains in 2-inch through 6-inch diameters. It is recognized that the standard does not regulate 10-inch roof drains.) In this particular series of tests, the 10-inch roof drain flowed less water than most plumbing engineers anticipated for a roof drain of this size. This accounted for the ponding around the roof drain, with the eventual collapse of the roof.

The other testing conducted, using the same test assembly, was of 4-inch roof drains. In this series of tests, the flow rate through the roof drain exceeded the anticipated f low as identified in the plumbing codes. While the plumbing codes do not identify the flow rate through a roof drain, they do identify the maximum flow rate through the storm drainage piping connected to the roof drain.

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Adaptive Reuse: Converting Offices to Multi­Residential Family

Adaptive reuse of commercial office spaces to residential multifamily offers opportunities to ease some of the housing shortage in the US. These types of construction projects have many challenges, from zoning restrictions, financing, and also controlling construction costs. Construction costs specifically can have a disparate impact on whether an adaptive reuse project is possible, let alone successful. Therefore, flexibility during the construction process is vital to the success of an adaptive reuse project. Codes for plumbing and mechanical systems that support design versatility and science-based methods, such as the Uniform Codes, will be essential for controlling construction expenses.

Capacities of Stacks and Horizontal Drains in Storm Drainage Systems

The sizing for storm drainage systems are dependent upon flow capacity equations used to calculate velocities and flow rates in pipe conduits. One of the variables in the equations is the coefficient of roughness. This paper explores how the roughness of different types of material will change the computational results that are dependent upon the roughness coefficient of the pipe.

Increase in Flow Diversity From Simultaneous Fixture Use: Impact on Peak Flow Estimate

In calculating peak water demand, there can be instances where an increase in fixture count results in a decrease in the expected peak demand. This white paper explains why this counterintuitive result can occur, especially when there is some probability of stagnation (i.e., zero demand). Using IAPMO’s Water Demand Calculator (WDC), we are not designing with zero flow in mind; hence, zero flows are ignored, and the 99th percentile is extracted from actual flows for any combination of busy fixtures.


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