HDPE for instrument air pipe
HDPE for instrument air pipe
(OP)
Is it common to have a HDPE pipe to distribute instrument air?
Currently one of the instrument air pipe is highly corroded due to the environment it is in.
I'm thinking of replacing the pipe with a HDPE PE 80 material with a pressure grade PN 12.5 or 16.
Currently one of the instrument air pipe is highly corroded due to the environment it is in.
I'm thinking of replacing the pipe with a HDPE PE 80 material with a pressure grade PN 12.5 or 16.





RE: HDPE for instrument air pipe
don't forget solar temp gain - PE doesn't like temperatures much above 40 to 50 C and de-rates quite quickly. Black PE tubing (you need black for UV protection) can get to 60 to 70 in a really strong sun, but depends where you are - Alaska probably not, but desert conditions....?
I suspect there are better alternatives than PE tube, but you need to ask some instrument engineers unless this is a large header.
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Also: There's usually a good reason why everyone does it that way
RE: HDPE for instrument air pipe
http://asahi-america.com/piping-systems-and-weldin...
Asahi thermoplastic piping systems using high-density polyethylene (HDPE), overcome the brittleness problems associated with PVC. They efficiently and reliably deliver compressed air with lower material and installation costs and longer service life than with metal systems. They offer a margin of safety missing from PVC.
These new thermoplastics are safe because they expand at the point of failure, tearing open rather than fragmenting dangerously. They do not accumulate scale on their ID, nor does pitting or corrosion occur, and they are unaffected by synthetic and mineral oils used in compressors.
http://hydraulicspneumatics.com/200/TechZone/Fluid...
RE: HDPE for instrument air pipe
There are stainless options if that works for you, including press-lock (i.e. Victaulic Vic-Press and others) piping systems if you can't tolerate threads and are too small to use roll-grooved piping (Victaulic, Grinnel etc.). We don't like the press-lock stuff much- we find the fittings too large and too expensive.
If you are indoors and in a corrosive environment where nonmetallics are the only really feasible option (i.e. an electrowinning facility where there's a lot of chlorine as a fugitive emission), there is or at least was an ABS piping system approved for instrument air- can't remember the mfg but a Google search should find them pretty quickly. The benefit of the ABS is that it's a solvent-welded rather than thermally welded system so the installation should be faster and cheaper than HDPE without the creep risk. But again, no ABS in direct sun exposure in my opinion.
RE: HDPE for instrument air pipe