I have a requirement to escalate a task and then fire a recurring escalation eve

Can you clarify on precisely what form your escalation will be? Send Message / Alert / email / etc?

The first thing that occurs to me, though this somewhat depends on your particular implementation, is that you could use the Timer Conditions in the escalation timer (e.g. screencast.com/.../g4MDUAHh20Jj ) to prevent the timer from firing when the current time (now()) is outside of business hours. There would need to be an external expression rule (in my example, "isInBusinessHours(time)", which would return a boolean based on your particular requirements.

(Note that I'm not 100% sure without checking first, that the "now()" function will re-evaluate properly each time the timer is due to fire, but I think it will.)

Great idea. I can confirm that now() is evaluated dynamically from within the Timer Condition every time it fires. Thanks for the help!

You can even use "calisworktime()" function as well to check whether your time lies in Business Hours or not. try using "calisworktime(now())". Point to note here is that the calendar has not been specified and it will take default calendar.