Best plumbing for homemade RO?

[cjf12]

I have my RO assemble with schedule 40 PVC but I haven't had the courage to glue it yet. 1/2 is rated for 600 psi. 3/4 is for 480. Plenty strong but OSHA will not allow it to be used for air compressor because of exploding hazards. Compressors usually dont run over 175 psi.
I see many people using kynar fittings with hose. The hose is only rated for 215 psi at 70 degrees.
What truly is my best option? Any one thread thier own pipe? Stainless steel?
Paranoid of using pvc and kynar if I run it at 250-275 psi.

[maple flats]

Find a food grade hose rated for 600 psi +. The pressure in an RO is pulsating not static, that complicates the issue. The only places needing the real HP hoses are between the HP pump and the membranes, then to the needle valve. After and before those you can use much lower pressure components.