I don't have a ready answer for you, not being up on all the different state requirements. However, there is a way you can find out with a bit of work. Just do a google search on professional engineer and the state you're interested in (and yes you might have to do it 50 times). You should be able to find a link to the official state web site for professional engineers. That site should have a link for you to contact someone to answer your question.
Or you could go to the national society of professional engineers (
The general requirement for most states is practice on one's area of professed competency. In states that license/register by discipline, an engineer must be licensed in that discipline to sign/seal such plans (such as for MEP). In states that do not license by discipline (I think this applies to most states), then the person must only sign/seal in their area of professed competence. For instance, if a graduate civil engineer takes the Civil exam and practices structural engineering for many years, then in areas of non-discipline registration would likely recognize that indivual as competent to practice structural engineering; however, other states (Illinois, California, etc.) might require (depending on building type/size)licensing as SE not CE.
Each individual recognizes when their knowledge is inadequate to take responsibility for a design. My instinct is to advise not to stamp a design if you cannot take full responsibility. However, other disciplines typically contribute to your design area. For example, I may size and select a control valve based upon my knowledge of valves, etc. However, the chemical engineers furnish my process data but they would rarely stamp the data. Some stamp documents with a notation that clarifies the limits of their approval. The limits surely differ by idividuals as much as by state requirements.
