Whats the requirements a security officer needs to know to work in a hospital

what experience does a security officer need to work in a hospital

None really I think just a high school diploma and open availability.

It's not the same everywhere. It depends on the criteria of that one hospital. Some employ off-duty police and retired sworn police officers for the experience and training. Otherwise the requirements would be the same certification as a security guard in that state or country like training in weapons and powers of arrest for example.

A security force can be an asset but untrained security people can be a serious liability also.