How to know vertical growth of X'mas tree

[Redpipe]

Hi all,

I am considering piping stress analysis of flowline downstream of X'mas tree. As we checked existing wellhead,we found that vertical growth of each X'mas tree are difference. So we used maximun vertical growth as worst case. This is existing platform.

However, In case it is new plant or platform, do anaybody know that how we can calculate design vertical growth of X'mas tree?

Thanks,

Dave