Do you want to know what makes me cringe? Usually when I walk into a concrete producer’s facility I ask, “Who is in charge of quality control?” Sometime I get a glib answer, “ Everyone is in charge of quality control.” When I hear this I want to grab the person I’m talking to and shake some sense into them, because their answer means that there is no one in charge of quality control. I’m sure you have heard the story of Everybody, Somebody, Nobody and Anybody, but it is a good story so I will repeat it.
This is a story about four people named Everybody, Somebody, Anybody and Nobody. There was an important job to be done and Everybody was sure that Somebody would do it. Anybody could have done it, but Nobody did it. Somebody got angry about that, because it was Everybody’s job. Everybody thought Anybody could do it, but Nobody realized that Everybody wouldn’t do it. It ended up that Everybody blamed Somebody when Nobody did what Anybody could have.
My father was fond of saying, “The only person who can control the quality of the work is the person doing the work.” However, there is a big difference between being in charge of the quality of your own work and being in charge of the result of everybody’s work. The person in charge of quality control should be a single individual who is not only responsible for the quality of the finished product, but also has the authority to make changes to insure that the finished product meets its requirements.
Of course, there are different levels of quality control. The QC manager is usually in charge of the concrete product itself, but the QC manager doesn’t control the activities of the Sales and Operations departments. A number of years ago Concrete Construction or The Concrete Producer published an article on the “Top 10 Complaints about Ready Mixed Concrete”. I can’t find the article, but as I recall most of the problems didn’t relate to the concrete but to operational aspects, like on-time delivery with proper spacing of trucks. Even operational issues relate to the “quality” of the delivered concrete.
While some operational aspects can be measured and have quality criteria applied to them, a lot of other things affect quality but can’t really be measured. It has often been said that the front-end-loader operator is the most important person on the yard when it comes to quality. After all, the loader operator controls the materials that go into the concrete. If (s)he lowers the bucket into the muck at the bottom of the stockpile, the quality of the concrete will suffer. There are a number of aspects to the loader operator’s work that affect the quality of the concrete.
Measuring the unmeasurable
So how does the QC manager monitor the work of others when most aspects of that work can’t be measured? The answer is – the lowly checklist. Checklists are everywhere. If you look on the door of a restroom at McDonald’s you will probably find a log sheet showing who from the restaurant has gone into the restroom each hour to make certain the restroom is clean and properly supplied. The log sheet is a form of checklist. Sure, it doesn’t have every little task on it, but how much goes into verifying a restroom is clean and stocked? Clean – check! Paper towels – check! Toilet paper – check! Done and out the door. If later a patron complains, it is easy to see who the last person was to check out the restroom.
On a more serious note, pilots routinely use checklists to perform a “pre-flight check”. Nobody wants to be 5,000 feet in the air and find out that they are running low on fuel. A pre-flight check can run from 20-25 items for a small plane, to thousands (millions?) of items for a space shuttle. For a small plane items might include rudder moves freely, ailerons move freely, fuel tank is full, oil reservoir is full, tires aren’t flat, and so on. Before you go on a long car trip you are supposed to do something similar for your car. Tires fully inflated? Windshield washer tank full? Gas tank full?
There are lots of checklists already in use in the concrete industry. The NRMCA and ASCC have gotten together and created a “Checklist for a Pre-construction Conference”. http://my.nrmca.org/scriptcontent/BeWeb/Orders/ProductDetail.cfm?pc=2PCHCKLIST
The NRMCA also has a “Quality Control Checklist”. http://my.nrmca.org/scriptcontent/BeWeb/Orders/ProductDetail.cfm?pc=2PQC123
Many contractors have a pre-placement checklist to verify proper setup of forms and reinforcing steel and the availability of the proper equipment and manpower before concrete is placed. The nice thing about checklists is that they can be as simple or as complicated as is necessary, as long as they verify the status of the important things. Also, checklists can either be formal documents that need to be filled out, or they can be laminated cards that aren’t filled out but are used as a guide for inspection. In the latter case it is recommended that whoever is using the checklist be required to sign a log sheet attesting that they have perform the checklist as provided. It is amazing how a simple signature can provide accountability and improve compliance with the checklist.
After the checklist has been filled out (or attested to) it becomes something that can be quantified over time. “The soft drink machine was restocked at the end of the business day 29 out of 30 days this month.” That represents a 97% compliance rating. Notice that we didn’t say anything about whether it was fully stocked, or whether it had the right combination of products. Those are separate issues. Also, the checklist or log file can be compared with customer complaints. “We had 3 complaints about the soft drink machine being empty, and John was the person in charge of checking the machine the night before in every case.”
Operational QC checklists
Of course this blog is about concrete and not soft drink machines. Where do checklists fit into a concrete producer’s operation? The answer is, “Almost everywhere.” When most people think about concrete quality control they think about slump tests, air tests and compression testing of concrete cylinders (or cubes for our friends across the Pond). However, these tests are all “after the fact”. They measure the concrete after it is produced. They are not quality control tools, they are quality verification tools. The only thing they can control is whether the concrete gets used on the project or not. To really control the quality of the concrete we measure things like aggregate moisture, batch weights, aggregate gradings, cement cube strengths and so on.
But what about the things we can’t measure? What about stockpile contamination? What about leaking water valves that allow water to be mixed into the concrete without being measured? What about an oil or grease leak that allows contaminants to drop into the concrete, destroying air entrainment? These are things that are never measured, but if we do a simple inspection they can be identified and corrected. The trouble is, “ Everybody expects Somebody to do it, but Nobody does it .” If people took a few minutes out of each day to look around their work area to confirm the proper conditions exist, a lot of quality problems in the concrete could be avoided.
Who can benefit from checklists?
- Front end loader operators – one for equipment and one for the yard condition
- Batch plant operators – Is the batch plant showing signs of wear?
- QC technicians – Is the equipment clean and operational? Are consumable supplies needed?
- Truck drivers – Is the truck clean, fueled and the oil level checked? How are the tires, water valve and mixer fins? What is the odometer reading and what are the engine hours?
Most people can benefit from a checklist. Even I, sitting at my desk, use a checklist of sorts to make certain that I don’t get distracted from the important things on my schedule.
After I create a checklist what happens? The checklist defines expectations of the person using it. If I provide a loader operator with a daily checklist that includes inspection of the yard for aggregate stockpile contamination, then I see stockpile contamination during my own weekly inspection, the loader operator has no excuse for either not resolving the problem, or at least reporting it to the correct people (if you have a checklist that needs to be filled out and turned in, the person receiving the report should be able to correct the problem.) Of course the loader operator needs to be educated on what is and what isn’t stockpile contamination. If there are multiple instances of a situation not being reported, the loader operator can be re-educated or reprimanded. In the opposite situation, if the loader operator consistently reports problems in the yard so that they can be corrected before the concrete is harmed, the operator can be rewarded.
How does all this affect the QC manager? If a problem occurs with the concrete and, because of the operation checklists, the QC manager feels that operational issues are not causing the problem, he can turn his attention elsewhere with confidence. Was a low strength cylinder caused by batching variations, a leaking water valve on the truck, mishandling of the cylinders at the jobsite, or improper testing at the lab? If the QC manager is knowledgeable about the plants batching tolerances and knows truck water valves are inspected daily, he can pay more attention to the jobsite and the lab.
Creating a checklist
How do you go about creating checklist for various operational areas? The first thing to do is to talk to the people who do the work in their area. Get their recommendations. Next, refer to technical documents. The American Concrete Institute has ACI 304, “Measuring, Mixing, Transporting and Placing Concrete”, which has a lot of great information on material handling and production. Also, the NRMCA has checklists for batch plant inspection and truck inspection.
In addition, I have just started a survey on the use of checklists at the concrete plant. Please add your own experience at . There is no point in reinventing the wheel. It has already been invented. I will post a summary of the results in a few weeks on this blog.
Finally, after the checklist has been created you have to get people to use it. Following are some tips on implementing checklists:
- Make certain the people using the checklists know that using it isn’t just busywork. Results will be checked and verified. People that don’t do it or fill it out at random will be reprimanded. If you can, provide an incentive system for people that use the checklists properly.
- Make certain the people using the checklists understand the items on it and know how to fill in the checklist properly.
- Develop a story or example for why the checklist was necessary, or why it was successful. “We had a load of concrete rejected because it had 3 inch aggregate pieces when the concrete was supposed to contain just pea gravel.” Or “We stopped a load of concrete from being produced when a load of rip-rap was dumped into the pea gravel bin. Good job, Joe.”
- Give positive feedback whenever possible. “Last year we had the plant conveyor belt snap 3 times because of wear and tear on the belt. This year, because of our inspection system, we haven’t had any belt failures during production.”
Do you use checklists to support operational QC? If so, I would love to hear about how it has worked for you and to see samples of your checklists. Feel free to add comments to this article or send me an email. Also, remember to respond to my survey at .
Until next time,