One of the more peculiar paradoxes of my life is that I spend two weeks every month in the Unites States, where much of my work deals with Lean process improvement, and two weeks in Haiti, where the concept process improvement is as foreign as, well, me. So I found great joy today in introducing ‘continuous improvement’ to our BLB orphanage project by creating a small template to ‘mistake proof’ the repetitive process of installing reinforcing in our floor slab.
There is over 50,000 feet of #5 reinforcing bars in the floor slab of the orphanage. The slab is going to be 9” thick with the bars running north/south and east/west in the top and bottom of the slab. The challenge is to keep the bars as far apart as possible for strength yet provide 1” of clearance on the bottom and the top for concrete cover – exposed bars rust and weaken the slab.
The crews are used to doing one thing completely, then the next, then the next (batching). They started to place the north/south reinforcing across the entire building but we asked them to finish a test area with all the reinforcing in place, tied off, at the right height, and ready for the concrete pour. This was a challenge to communicate but eventually they completed one room.
The variance was great; some top bars were too low, others too high, some too close to the face of the slab. I took out my tape measure and began explaining in pigeon Creole the different dimensions required but it was hopeless. There are too many variables in placing reinforcement and they all relate to a phantom plane, the top of the slab, that no one can see. That’s when Lean thinking popped into my head – make it visual, make it mistake proof.
After the crews had gone, Gama and I cut some plywood into a simple template that the workers could slip into the rebar top and bottom. The template provides a clear line at the top and bottom of slab for visual reference, and shows exactly where the rebar needs to nest. The rough cut we made out of plywood was not quite right, so I refined its proportions at actual scale on a piece of paper and the next morning the carpentry crew cut one out. We took it to where the rebar crew was placing and tying reinforcing (go to Gemba) and it worked well, so one carpenter spent the morning building seven more. Every member of the rebar crew got one, as did I, mister quality control.
It took the workers a while to get used to the jig. First they tried to muscle it into place. Then they realized that the point was not to force fit the rebar. I checked in every hour or so and in mid-afternoon, as four of them were finishing up the second room, they smiled up at me and shouted, “Good! Good!” Leon, the crew boss, sturcxk the pose for this photo, showing off his new work saving device.
Leon and his new tool