Yea, you will totally receive an orientation session. I would not advise wearing srubs,however, have encountered many suspected nosocomial infections recently. If you wanted to,I am sure they would allow you to;however, you might confuse the patients. They would start asking you questions that would be beyond your scope of limitations(hopefully, unless they are allowing volunteers to perform surgery).
First of all the biggest and largest concern would be that of your patient interaction. You will talk to people who are somewhat content and understand the process;while, on the other hand you will experience a round crowd of people. You must be respectful and understand patient privacy is a top concern. You are expected and required to speak professionally.
For the most part you will not endure long conversations with patients; most are inaccessible due to conditions. The relatives are the people you will sustain the most communication with(outside of hospital staff).
What kind of department are you asking to volunteer in?