I searched the site for info on FRP. I found reference to an article on frp modelling but the link is not active. Is this still available?

This article hasn't been converted to the new format of the redesigned website. However, this article has been moved into the formal documentation. In Version 4.50, you can find this in the <font color="#0000ff">Technical Reference Manual</font>, beginning on page 6-61.

Hi
Just to caution on the FRP piping characterestics. If the plant is having quite a good number of FRP lines, make sure you involve the prospective Vendor at a very early stage.
The properties will vary from Vendor to Vendor.

Have a look at ISO 14692 Part 3 for a good guidance on GRP design.

Bottomline: Once cracked, the CRACK in FRP will propagate fast. So make sure there are less Bending moments. Take advantage of the low axial Modulus of elasticity.

The support spans will be much lesser than steel pipes.

You can expect large axial displacements due to Pressure effects contributed by the Low axial modulus .