Swim has recently discovered a special type of pvc will also work with all anhydrous ammonia related setups. The material isn't cheap, some beleive it better than stainless steel. It is a material called cpvc or corzan pvc. It has any chemical application that comes to mind also. I have seen it used also with Chlorine gas,highly caustic substances and more.
Corrosion resistant pressure pipe, IPS sizes 1/4" through 16", for use at temperatures up to and including 200°F. Pressure rating (130 psi to 1130 psi) varies with schedule, pipe size, and temperature as stated in Harvel Plastics, Inc. engineering bulletin (Product Bulletin 112/401). Generally resistant to most acids, bases, salts, aliphatic solutions, oxidants, and halogens. Chemical resistance data is available and should be referenced for proper material selection. Pipe exhibits excellent physical properties and flammability characteristics (independently tested flame and smoke characteristics- ULC,1993). Typical applications include: chemical processing, plating, high purity applications, hot and cold potable water systems, water and wastewater treatment, and other industrial applications involving hot corrosive fluid transfer.
http://www.harvel.com/piping-cpvc-apps.asp (http://www.harvel.com/piping-cpvc-apps.asp)
There is more info as to specific chemicals located in this website.
Swim was dreaming of running a stainless steal nipple from annie tank(tilted sideways..chilled) to Cpvc adapter to ball valve and connecting another peice of cpvc piping to valve and configuring pipe design to run into rxn vessel.
Whats the opinon on this idea