Many times, when we are designing static and rotating equipment, it starts with a specifications sheet that lists the performance expectations and requirements. Most often, it is the case that any startup or shutdown requirements are not listed. For static equipment, this could be heat up rates, or sequencing of process feeds to the equipment. For rotating equipment, it could be ramping conditions through critical speeds. Many times during the startup of a plant, opportunities for relatively high transient loadings are present. Let’s discuss a few examples to “home in” on some design considerations. The first example is the heat up rate of thick walled reactors and heat exchangers.