How do you come up with duration times for activities?

[grncivic03]

Im working on a class project and I do not know how long it would take to put electrical and plumbing in a 25 story hospital.

Would you just break it down on how long it takes to do a square foot at a time?

[Rich]

Typically you would have input from your electrical contractor, or you would set the duration from what it has taken historically within your previous jobs, or it would be whatever fits within the schedule. If your electrical activities are critical path activities, you would need to set the durations so it won't kick out the contractual end date.

[Willie T]

Have you checked out your R S Means? Involves a little more work on your part, but it also may help keep you from graduating as one of the thousands who can add up the numbers, but really have no true idea of what they added up.

[buratino]

Hi guys! I am doing my first ever construction programme. Having no site experience I am getting it very hard to guess durations of the construction activities. So i was wondering if any of you have generated their own list of average durations throu years of experience,or can guide me to where i could find these. I know you can do calculations of all the activities, but for that you need to know the production rate and the crew size, i do not need to go to that extent.

Or any of you might have examples of microsoft project programs???
Any help will be greatly appreciated.