CVPV within return air plenums

[Shredocaster]

Good day, All

I see that running cpvc in a return air plenum for the most part is alright with exception of running the line directly above a return air grille (no cpvc lines to be above the horizontal). It would appear then that running cpvc behind a return air grille on the vertical is ok.... or is it? Opinions and/or facts appreciated.

 

[stookeyfpe]

You're asking a Mechanical Code question, not a CPVC or NFPA 13 question. Requirements for what is allowed or not allowed in a return air plenum are found in the jurisdiction's mechanical code. Do you know what edition or which mechanical code is applicable?