# Insulation Covering Hydronic PVC Pipe In A Return Air Plenum Ceiling Space



## gmgitt (Jun 21, 2011)

In an effort to meet IMC 602.2.1 Materials exposed within plenums, is acceptable to wrap hydronic pvc pipe with ASTM 84 E 25/50 Flame/Smoke rated insulation per:

602.2.1 Materials exposed within plenums.

Except as required by Sections 602.2.1.1 through 602.2.1.5, materials exposed within

plenums shall be noncombustible or shall have 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 E 84.


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## Francis Vineyard (Jun 21, 2011)

gmgitt

Welcome to the forum. Aware that some AHJ will not approve certain materials whatever their reasons however the exception item five invites other than the prescribed enclosures the approved material must be listed and labeled. Tests have shown when the PVC is filled with water will meet ASTM E 84, but what's the guarantee that water will remain at all times.

"5. Combustible materials fully enclosed within continuous noncombustible raceways or enclosures, _approve_d gypsum board assemblies or within materials _listed_ and _labeled_ for such application."

http://multimedia.3m.com/mws/mediawebserver?mwsId=SSSSSu7zK1fslxtUoxt148_Zev7qe17zHvTSevTSeSSSSSS--&fn=3M%20FB%20Plen%205Apls_PDS_4631-1.pdf


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