Managing Uncertainty on Site

These are turbulent times that we are in and variation is extremely high right now in April 2020. The concepts of buffers and how and when to use them is not a common discussion in Lean in Design and Construction. Sometimes they happen on the side or inadvertently. But now is the time that we need to be extremely conscious and deliberate in our discussions and use of buffers.

First off, what is a buffer? A buffer is a tool that we use to manage against uncertainty and fluctuations within our production systems. It is part of our risk identification and management strategy. The three main buffers that we can use are manpower, material or schedule (time).

In a normal construction project it is common to hear the superintendent say to a trade craft partner to “get more guys”. That is typically because he feel that production is not where he feels like it should be. But it could be because he sees upcoming work and wants to be prepared for this work. Or it could be because he feels more comfortable with an ant hive of available workers ready to “go to work”. Well this mentality leads to the waste of underutilized talent. And in our typical market of tight margins on projects this doesn’t happen all to often. Also, our trade craft partners do not typically have a corral of staff waiting back at the office waiting to be deployed. This is even more so now with the restrictions on staff if they are not feeling well to be not available. And fewer people are available for the demand at the projects. So we cannot rely alone on just getting manpower anymore.

Material can be an easy buffer and our contracts typically encourage us to use these unwisely. We are incentivized to bring lots of material to site as we are only paid on that material when it is landed on site. The only times where we are typically restricted from bringing material to site is when there is just a physical restriction to being able to place the material there. Having too much material on site can lead to waste. The material can get damaged or lost. The material is in the way and needs to be moved somewhere else which ties up manpower that could be focused on value added tasks. This is where the concepts of Just-in-Time delivery come into play. Ideally the material is unloaded and put directly into its final place. That is not always practical and appropriate for the risks that we have to analyze. Is the material readily available in small enough loads, then we could consider ordering smaller loads as demand calls for? But for rare material that has to cross international borders, or material that takes a long time to produce and the impact to the project would be great if we missed our deadline then we need to size the buffer appropriately and get that material there potentially sooner. We just have to be conscious of that decision. I was on a project recently and the freight elevator was inoperable for a month. When it did become available again the decision was made to get all the required material on the required floors as waiting for the elevator would impact the project immensely. Later the elevator was inoperable again for a week, but it didn’t affect the project.

The last buffer is time or a schedule buffer. There is a great discussion on how we implement these buffers on our projects. Due to the culture of deception, and “grinding” of our craft partners on schedule they like to include extra days in their time during the pull plans. Once a culture of trust has developed on a project that we will respectfully hold each other accountable and we use missed promised dates as learning opportunities the duration tend to be more realistic vs pessimistic. Another way that we use time buffers is that we build our schedules on a 5 day single shift schedule, so if a craft partner is falling behind their commitment they can work later hours and or they can work on Saturday. These are not always feasible as there may not be an allowance for overtime work premiums. If every trade partner carries the buffer we tend to have production plans that exceed our phase durations. One discussion that I have been involved in is that the General Contractor should hold the buffer and make it visible in the pull plan for all to be aware. This is very hard for many to do as it hasn’t been done before a lot and requires trust among the partners.

If we trust our craft partners and empower them with information then they will work with us to help the project out. This is a different way of working than what has been done for thousands of years in the construction industry. Not only do we have to be open and honest with our craft trade partners, we also have to be open with our design partners and the owner of the project. We can explain our methodology on which buffers we are using to manage which risk, which shows our expertise in managing projects. By engaging everyone in the value stream we can turn over great projects to great clients.

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