Gabriela Uribe, a Plumbing Designer with The Interfield Group, is working on a three-floor medical office building in Harris County, Texas, in which the second floor has two operation rooms and one procedure room. Her team installed Schedule 40 PVC for the DWV and condensate lines, but the medical gas installer said they could not use PVC on the second floor because of the rooms located there.
Wondering it this was true and, if so, why, Gabriela started a discussion thread on ASPE Connect to get advice from our experts. She asked, “Do we have to replace the pipe with a different material or is there something else we could do?”
Check the Code
As with most plumbing design questions, you first should consult the code approved by the local authority having jurisdiction (AHJ). For instance, no PVC/ABS piping can be installed in an OSHPD facility in California since this is against CPC Section 701.2 (2)(b), according to Artin Haroutunian, CPD. Similarly, up until the early 2000s North Carolina did not allow any PVC piping in hospitals, says David Lewis, FASPE.
In Harris County, the state plumbing inspector is responsible for reviewing MEP drawings, and Ben Van Alstyne has found Texas as a whole to be very strict regarding MEP code requirements.
While more information about this specific project would be needed during the consultation with the local AHJ, the restriction on PVC in plenums can be found in the International Mechanical Code (IMC), Section 602.2.1, which states: “Materials within plenums shall be noncombustible or shall be listed and labeled
as having a flame spread index of not more than 25 and a smoke-developed index of not more than 50 when tested in accordance with ASTM E84 or UL 723.”
Can PVC Be Used?
The short answer is yes, if the PVC is fire-wrapped. Marc Bedois, CPD, has seen PVC pipe installed in a plenum space wrapped with foil-faced fiberglass insulation to meet the flame spread and smoke-developed index requirements of IMC Section 602. However, when confronting the issue of using PVC in a return air plenum, pay close attention to Exception 5.3 in IMC Section 602.2.1, as well as the accompanying IMC commentary, says William Sherrer, PE, GPD.
Also, be aware that medical/hospital facilities may not want PVC because it’s noisier than metal pipe, and the operations in certain rooms may be sensitive to noise, cautions Greg Farzetta III, LEED AP.
For further insight on this topic, visit the discussion thread on ASPE Connect.
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