It's been many years since I dealt with FRP.
FRP is not as easily inspected as steel. You cannot perform a volumetric analysis of a secondary bond the same way as you can perform a radiograph of a weld. The quality control side of things is much more complex as a steel tank or pressure vessel may have 20 "parts" which you trace heat numbers where an FRP tank may have 1000 different pieces of glass.
To answer your questions above relative to the differences between steel and FRP:
Design - steel is essentially the same in all directions, FRP you tailor the properties of the laminate to the directions where you need the strength.
Materials - steel is provided with a mill test report that states chemistry, tensiles etc. FRP you may get some information on the glass and the resin but the end properties depend on how you put the two together.
Fabrication - It's been a while but I believe that ASME X requires some type of qualification for secondary bonders. If it does not it would be a good idea to perform some type of qualification test. That way you have proof that the people doing the work are good at it.
Testing - For steel there is radiography, dye penetrant, and others. FRP there is visual, accoustic emission, visual, and more visual. The importance with FRP is to have skilled inspectors who know what to look for with FRP laminates.
I am not familiar with BS 9449 so I cannot comment on how it compares to what I have mentioned above.
EJL
