Pull planning

As if we didn’t already have enough to do, I’m sure many of you are familiar with and frequently hampered by the concept of pull planning. I don’t mean to be negative, or irreverent, of the benefits of the process of pull planning. But, it falls into the category of something I have written about in the past, and that is things that add to the complexity and time absorption to the engineering process (which are not necessarily incorporated in our fees — i.e. things we give away for free). 

Pull planning is a process of reverse scheduling that is performed to help ensure that milestone dates are met. In that raw form it is very practical. It is no different from when you think to yourself, “Self, if I’m going to be at dinner by 7 p.m. I will need an hour to drive there, 30 minutes to get dressed, 30 minutes to shower and shave, so I better be in the shower by 5 p.m.” Simple. We do it every day.

The Lean Construction Institute has popularized pull planning for the construction industry. It is no longer just a method of reverse scheduling — it has been formalized into a ritual that involves a room full of people for an entire day. To be honest, it is not the most efficient use of time, but it is a sort of team-building exercise that helps initiate the design and coordination process, and gets everyone to start thinking about what they need from others and what they need to provide others in order for the design process to flow fluidly. It also serves as a basis of a design schedule for the general contractor. But again, it is one of those obligations that most of us don’t have built into our design fee, so in essence we are doing the exercise for free.

According to Lean Project Consulting, “One of the keys to success in designing a production system based on lean principles is to get all of the work experts who are supervising the work, we call them last planners, to engage with each other to collaboratively work out a plan for the phase that includes the best of the alternatives available to them. Facilitating that conversation can be a challenge …”

So to put things into practical terms, a pull planning design meeting occurs early in the project design process and involves all of the key decision makers from the various disciplines. Each company or discipline is assigned a color of sticky note pads and a row on a large scheduling chart on the wall. Each sticky note has a matrix of information. 

The pull planning sticky note format

The sticky note represents a critical piece of information requested of or promised by the design professional. These notes, once written out, are pasted on the wall in chronological order such that it creates a big rough schedule chart. 

 Pull planning in process    

According to LeanConsruction.org, the pull planning steps are:

  • Define the phasing of the work
  • Determine completion dates for the phases (or milestones)
  • Using team scheduling and sticky’s on a wall, develop the network of activities required to complete the phase working backward from the completion date
  • Apply durations to each activity with no contingency or float in the estimates
  • Re-examine logic to try to shorten the duration
  • Determine the earliest practical start date
  • Decide what activities to buffer or pad with contingencies (Which activity duration is most fragile? What are the risks?) 
  • Rank order by degree of uncertainty.
  • Allocate available time to the fragile activities in rank order.

Is the team comfortable that the available buffers are sufficient to assure completion within the milestone? If not, either re-plan or shift milestone as needed and possible. A practical example of how this is done is as follows. The electrical engineer needs your electrical loads to size his generator and incoming service. He needs this information by a certain date to progress with his design, so you will have to provide him your electrical loads at least a week or so before his critical date. So, these milestones will determine where your sticky note that says, “Give electrical load information to electrician,” gets placed on the schedule wall. 

Once all the notes are on the wall the general contractor typically uses it to create the composite pull plan schedule and distributes it to the team. Most of the activities described are performed by the general contractor, not by you, the plumbing engineer. But it is important to understand the process and what role you will play. This way, should you be called to attend a pull planning meeting you will know the process and understand how to create your sticky notes and what they will be used for. When the sticky notes are written, you will put them on the wall where you think they belong. However, in all likelihood, if the pull plan facilitator is a good one, your notes will be moved around such that they jive with the other activities surrounding them.

 

Timothy Allinson is vice president of Engineering at Murray Co., Mechanical Contractors, in Long Beach, California. He holds a BSME from Tufts University and an MBA from New York University. He is a professional engineer licensed in both mechanical and fire protection engineering in various states, and is a LEED accredited professional. Allinson is a past-president of ASPE, both the New York and Orange County chapters. He can be reached at lagunatictim@gmail.com.

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