Construction Schedule I. Activity Time

The activity duration is calculated based on norms, and the schedule and project lead time are obtained by applying various logical relationships between activities. However, before diligently creating a schedule, we must know the steps for defining standard time (normaidő) and activity duration.

Relationship between standard times and activity duration

In my previous article on Building Construction Budgeting, I already discussed standard time (normaidő). Standard time essentially shows how long a given process takes with a given resource. To determine the standard times for processes, we use the Építőipari Műszaki Iránynormák (ÉMIR – Hungarian Technical Norms for Construction). Various companies conduct measurements for these – practically with a stopwatch. Of course, some manufacturers also create their own.

Activity duration, activity list

Now that we've learned what the standard time for a given process means, I will show you how to calculate the associated activity duration.

After we have determined which processes make up the schedule and have hierarchically organised them, it is advisable to create a table for this so-called activity list. In my opinion, using Excel for this makes it much more transparent, and modifications are easier to manage.

Activity list detail

I took the example above from my diploma thesis. Here you can see the technological steps of the foundation work (pad foundation, ground beam) for a prefabricated hall.

Let's go through the columns one by one for easier understanding:

• Serial number
  • this serves for easier identification later
• Item number
  • here it is advisable to enter the previously mentioned ÉMIR item numbers to avoid any misunderstandings later ("that can't be that much", "that's too much")
• Activity
  • the designation of the previously defined technological processes
• Quantity
  • data previously determined from plans and budget
• Unit
  • the dimension corresponding to the listed item
• Norm
  • we have already discussed this (see beginning of the article)
• Brigade
  • the norms always refer to one brigade, however, if we want to speed up the activity duration, we should work with more brigades, within reasonable limits, of course
• Time total
  • quantity x standard time = activity duration
• Time day
  • since construction is not usually scheduled down to the minute, it is advisable to round the calculated activity durations to days
• Resource
  • each activity has one or two human and machine resources (it is important to know the minimum brigade size for a given process)

Summary:

As we saw earlier, determining the duration of an activity is not very complicated if we know the quantities and where to find the specific item. In my opinion, it is always worth creating an activity list that includes how everything was calculated. This easily modifiable table will also be needed later for schedule optimisation.

Sources:

Internet

YBL lecture notes

own experience