Hi All,

According to B31.3 piping systems which meet the criteria in section 319.4 shall be analysed.
But for nuclear code NB what will be the criteria to decide that which lines come into cirtial .

There are many other criteria that will flag a line as being critical, in addition to those indetifid in B31.3 319.4. and those are largely decided by the engineering contractor's procedures, or the Client's or both. For example, B31.3 para 319.4 makes no reference to strain sensitive equipment connections, since it is specifically concerned with flexibility, i.e. thermal or displecement stresses.

Likewise ASME III NB will give a certain amount of guidance, but there will be far more conditions that will make a line critical in addition.

Thank you moverZ