There are basically two types of clad pipe, metallurgical bonded or mechanically bonded. The metallurgical bonded is more expansive are better. I have come across research papers where the steel clading has been used for pressure containment but this is seldom used. As Richard has mentioned the clad thickness is usually ignored for stress calculation.

If your pipe is mechanically bonded be careful about production quality control. There have been cases where the contact surface are not properly cleaned and when exposed to high temperature, the cladding can boughs inwards due to steam trap between carbon steel and cladding contact surface.

Mechanically bonded clad pipes are restraint by a seal weld. Be careful about the differential expansion force (carbon steel vs cladding) acting on these seal welds. Get confirmation from vendor that 450 deg F is OK.

Others,

Be careful about upheavel buckling.
Be careful about temp derating properties of carbon steel (and cladding if you are considering its strength)
Be careful about your corrosion coating selection.
Be careful about your welding procedures, how to handle cutback etc.

That about all I can think of the time.