By Dennis Sowards
Masaaki Imai, Lean guru and author of Kaizen & Gemba Kaizen, likes to say, "If you are spending lots of capital to do Lean - you are not doing Lean."
Many contractors, who are trying Lean in construction, are not really doing Lean by this definition. They are spending big bucks on BIM and calling it Lean. Not that using BIM is wrong, in fact, it has great value when applied correctly. But BIM is not Lean and does take a large investment to get set up, train personnel and to learn how to apply.
Lean is a simple, common sense approach, though often not a common practice. Consider the following examples of applying Lean
Henry Ford would say, "Make it can't, Not don't." Poke Yoke means to error proof work so one cannot make a mistake. One example of this in construction, is marking duct with a grease pen showing exactly which end connects with which end. This may not prevent a mistake but greatly helps to prevent it.
Simple, Visual Boards
When workers know the goals and work assignments each day, they usually are able to do a better job. Some contractors feel they need to install electronic signboards to display the daily and weekly work plans. The simple Lean approach is to use a white board with markers. It is not high-tech but works well and is much less expensive. It also sends a message to the workers to use simple solutions not expensive ones.
A Lean way to understand the path material or information takes, is to do a spaghetti chart. Using a map of the work area, one walks and marks the actual path of fabrication (shop), material installation (from the yard lay-down area to install) or purchase order processing (office). The Lean principle is to "Go and See," and the spaghetti chart allows simple and useful documentation.
Rules of Release
Work-arounds are all too common in construction. One Lean tool to help address this is to get both the giver (supplier) and receiver (next in line customer) together and identify the rules (requirements) for releasing or handing off work to the receiver. Both parties collaborate to define in detail what must be done or be ready to release work. Identifying and agreeing on the hand-off requirements is not hi-tech but can be very effective in creating workflow and eliminating rework or work-arounds.
Some contractors are investing big dollars in material management systems, including bar codes and scanning devices. From a Lean standpoint, we want to ensure that the shop fabricators and the install crews never run out of the material they need to add value. A simpler Lean tool is the Kanban approach. Refill levels are marked visually and a card containing the reorder information sends the signal when it is time to refill. When used consistently, Kanbans can eliminate workers waiting for material and keep the amount in inventory to a reasonable level. The bar coding approach often fails when workers do not remember to bar code every item used, causing the inventory levels to read higher than reality. The Kanban visual approach does a better job of signaling when to reorder, and for a lot less time and capital.
Most contractors use project management tools such as Primavera to schedule their work. They invest many hours in entering and updating the schedule. Some level of a master schedule is useful, but a hand completed six-weeks look-ahead check list is much more effective in making sure the work tasks are ready to be done when scheduled. The electronic schedules focus on "time" (which week) as the change variable, while the look-ahead plan focuses on making work ready.
Mr. Imai also says, "If one is not doing the 5S's one is not doing Lean." The 5S's are a valuable Lean tool to reduce or eliminate treasure hunting so common in construction. By moving tools and needed equipment close to where the work is being done, the waste of movement is attacked. One example is using duct tape to mark where finished fabricated product for each job should be placed on the shop floor. As jobs change and the quantity of fabricated product for that job changes, the tape can easily be adjusted to suit. On job sites, workers often reuse cardboard boxes to hold material. A grease pen can be used to mark on each box its actual content, thus avoiding a treasure hunt of workers looking in each box.
As an industrial engineer, I am always interested in how contractors measure productivity. I have yet to find real useful measures being employed. Managers fool themselves thinking that such measures as feet of pipe installed per hour or tons of steel erected per day really measure crew productivity. The best measure I have found is PPC - Percent of Planned (work) Completed. While this is not a true productivity measure, it is a more useful one. It measures the effectiveness of the planning system which includes the foreman, superintendent, crews, PM and even the GC and other trades. It is a simple measure to understand and track. Research shows that crews, not doing Lean, only do about 54% of the work they planned to do each week. Using PPC as an indicator and implementing Lean planning techniques can raise PPC into the 70 - 80% range. (If it reaches 100% and stays there, then someone is gaming the system. But that is another article.) It is logical and proven that when crews do more of the work they planned each week they are more productive.
One straight line
One story from a manufacturing shop illustrates the whole idea of simple Lean. A company had a large machine that had over 200 bolts holding it together. Each Friday a worker had to check each bolt to make sure it had not vibrated loose. This was time-consuming, tedious work because the worker had to put a wrench on each bolt to try and tighten it. One worker suggested that after each bolt was tightened to draw one straight line from the bolt to the flat surface it was touching. The next week the worker could visually see if the bolt needed tightened by how well the line on the bold lined up with the line on the surface. This made the weekly job faster and easier. Where would one straight line simplify your work? (Story courtesy of Norman Bodek.)
There are many ways to make work more efficient without spending scarce capital funds. Lean is simple ideas applied to eliminate waste--make it a common practice.