Elevating Construction Foremen – Part 23

Imagine your college assignment is due Sunday. You grind and finish Thursday. The professor writes back: thank you, and since you are done early, I have moved up your next due date by three days. Your nap, your night out, your day at the beach, gone. Would that student ever turn in an assignment early again? No. And yet that is exactly what construction does to crew leaders day in and day out.

This is Part 23 of my walk-through of my book Elevating Construction Foremen. If you are just joining, start with Part 1. This part is about leveling work: production rates, takt zones, work packages, labor counts, just-in-time materials, and buffers.

Short answer: Little’s Law says work goes faster when it is leveled, so work like the tortoise, not the hare. Crew leaders level work by backing durations with production rates, watching takt zone size and configuration, leveling work packages, right-sizing labor, bringing material just in time, and protecting a buffer in every work package. You could be the best in your field and still be limited by any one of these.

What Does Leveling Work Mean?

Leveling work means things are even and going the same speed, distance apart, and direction. It means no spikes, no starts and stops, and no high variation. Production systems work very well when they are leveled. Here are the levers you can pull to level your work and help level the whole system. More in Heijunka: Leveling Work for Flow and Predictability.

Why Should Crew Leaders Use Production Rates?

One of the best ways to level work packages and truly understand work density within zones is to use historical production rates based on quantities. Your opinion about how long something should take is valuable and deserves to be backed up by production rates. Accurate durations let you package work into a takt wagon, the amount of work within a zone by the takt time, so the sequence and zones can be leveled. Production rates will substantiate your opinion and keep you from being pushed into impossible durations. You could be the best person in your field and still not accomplish the work if you have an unrealistic duration.

How Do Takt Zones Affect Your Speed?

Watch three things in your takt zones: the configuration of the zone and whether it lets you flow, whether each zone has an equal amount of work, and the number of zones in the phase. The smaller the zones, meaning the more zones you have, the faster you will go. There is a point of diminishing return, and we know large zones make you go slow, so the best size is somewhere in between and likely on the smaller side.

The zone outline can be a coordination between you and the team. The number of zones can be calculated with Little’s Law: takt wagons plus takt zones minus one, multiplied by the takt time, equals the duration. This works for zones in a building, on an exterior, on a site, on a run of pipe, or for a grouping of equipment. Your zone sizes will restrict or enable your pace.

Why Must Work Packages Be Leveled?

Work packages combine multiple steps in a process. One or more work packages make up a takt wagon, the work at the intersection of a takt time and a zone. Do the trades go through the zones at different sizes and speeds? No. They must move fairly leveled and at the same speed, like a train. What happens to a train if one boxcar is overloaded? It slows, stops at bridges and tunnels, and likely derails on curves. The train will only go as fast as the slowest work package.

Work packages may need to split or combine with others. Some may need two crews. If you have a small amount of work in one takt wagon, you are wasting time. If you have too much, you are slowing down the train. As a crew leader, it is your job to watch this and raise your hand if you see a problem.

How Do You Adjust Labor Counts to Level the Train?

You may need to adjust the number of trained people on your crew. I remember leveling a sequence where we had planned a four-person crew for overhead fire sprinkler installation. The work in each zone would only take a day, but the takt time the project decided on was two days. So the crew leader adjusted the crew to two people, and they stayed in a continuous flow. We want the right amount of trained people, and possibly just a little more, but not too many. You will never go faster than the productivity loss of too few people, too few of the right people, or too many people.

Why Bring Materials Just in Time?

Bringing materials just in time means getting them to the place of work just when they are needed, whether from the vendor, from a laydown, or some mix of the two. You cannot have workers waiting on materials, and you cannot have too much material stocked on the floor getting in your way. The takt rhythm gives you solid delivery dates by zone, and those dates should all have buffers to absorb supply chain delays. They are also the dates for final confirmation and six-week make-ready planning. It is the crew leader’s job to help manage this with the project team. See Just In Time Materials – Lean Series.