ServiceNow does not support any fields like the one you are looking for. I would suggest an alternate like this:

1. Use time worked field.

2. Write an on load client script showing  a field message like "Maximum time of evaluation is ....."

function onLoad() {
   //Type appropriate comment here, and begin script below
   g_form.showFieldMsg("time_worked","Maximum time of evaluation is 5 min or 00:05:00..");
}

3. There are a couple of properties which are available for the timer fields to play with. 

Do not hesitate to mark the answer as correct and helpful if it was 🙂