PCHE pressure drop assumption will depend on the type of process:
Generally in systems where fouling is predicted the pressure drop for the clean printed circuit heat exchanger shall be restricted to 90 % of the allowable value.
In addition pressure drop losses should also include all those occurring in nozzles, header tanks, bends, fittings, manifolds, distribution, thermal sections, etc.
The pressure drop for the strainer shall be additional to the stated printed circuit heat exchanger pressure drop.