When drying out a unit or vessel that has multiple refractories, schedules should be based...

When drying out units withmultiple types of refractories, API 936 and API Technical Report TR 980 emphasize that the most conservative dryout schedule must be followed to avoid premature failure orexplosive spalling. This meanschoosing the refractory material or lining system that requires the longest duration or slowest heating rate.

Different refractory types—gunned, cast, plastic, or fiber—have varying sensitivities to moisture and thermal gradients. Selecting the schedule with the longest duration ensures full water removal, especially from thick sections or materials with high water retention capacity.