Pipe loops - polypropylene pipe

Dear all,

I need advice regarding design of piping loops for polypropylene pipe.
Working fluid 50% phosphoric acid, temperature 20 C, discharge pressure 4barg.
Pipeline is outside and temperature difference is T2-T1=30C

I want to compensate thermal dilatation using piping loops. Linear expansion coefficient for polypropylene is 0.16 mm/(mK), which is around 10x more than for steel pipes.
According to my calculation, number of piping loops (3m width, 1.5m long), on the distance of 100m is around 10 pieces which is a lot.
I probably misted/forgot some detail.

Does anyone had similar experience with PP pipes?

polypropylene pipe is a strange animal.. and a piping system with it has particular challenges: lets start with the basics
what size piping has been specified??
is the flow constant or intermittent??
Has a pipe manufacturer been selected??
what is the proposed pipe routing???

and as always - 1st take the initiative and investigate your post on the internet.. less than 30 seconds time led to this:
www.plasticpipe.org/pdf/chapter06.pdf