gow,

While you will do best to pick the brains of your local senior engineers, there are some resources available now that can help you progress. Two books to take a look at:

Pipe Stress Engineering by Peng http://amzn.com/079180285X

Process Piping by Becht http://amzn.com/0791802868

Neither book is cheap, but the offer a lot of good info to get you moving in the right direction.