There is a similar question regarding capitalizing units of measure, but mine is for titles, specifically. For general applications (ie; not inside titles), the consensus seemed to be no for most units (although there were a few special cases mentioned). I am wondering whether this changes for titles. And if so, how it changes. Should you capitalize the first letter? The entire thing?
My specific example is for pounds per square inch (psi). "Tire psi Below Minimum" vs. "Tire PSI Below Minimum" vs. "Tire Psi Below Minimum".
Edit: The commentator below raises a good point. But what if it's "Tire Below 72 PSI Requirement"? I don't see a way to get around using a unit there.
More info: These titles are used as alert titles to display to a user in an application.