InsideARM, defines time-barred debt this way:
“Accounts on which no lawsuit is commenced before the statute of limitations expires are sometimes called “time-barred.”
While the laws apply to business debt as they do for consumer debt, time-barred debt in the collection industry doesn’t tend to be as much of an issue for commercial debt. Commercial debts move along pretty quickly in the grand scheme of things. A debt is typically resolved or the company goes out of business long before the statute of limitations would apply.
Even so, this article by InsideArm, How To Collect on Time-Barred Debt is an interesting overview of handling accounts past the statute of limitations.