Hot mix asphalt plants Part II:A pathway to success
February 6, 2020 By Ken Monlux
In my previous article published last issue, we discussed a method of collecting, evaluating and distilling data into a user-friendly matrix called The Log. The collected raw data is organized in a way to be quickly absorbed by the local manager. All the reporting in the world is of no value, if it is not read, understood, and acted upon.
Like in our baseball example from last month’s article, teams were dissatisfied with the result of their scouting and statistical review. The owners were not getting the result they desired. Could it be, that the hot mix industry is also unhappy with their current reporting?
Let’s take a deeper look at a log-based platform. When studying The Log, the first thing you notice is the layout. By design, The Log gives you a lot of information, quickly, and simply. Unlike traditional formatting, it is not a top-down summary report. It’s structured to be site specific and designed for the local manager. It is intended be interactive and to challenge the supervisor.
The core of The Log is three-fold:
- Vital signs: A quick look at the health of the operation;
- Evaluation: Analysis of raw data in real-time in order to challenge the team; and
- Archive: Ability to easily reconstruct any given day of operation.
If you are ready, let’s take a more meaningful look at these core principles.
When you visit your doctor, the nurse checks your personal vital signs. Such things as blood pressure, weight, and pulse are documented and compared to past visits. During the visit, the doctor will evaluate your vital signs. Based on these vital signs, the doctor can then go forward in a diagnosis. Like you, a hot mix operation has vital signs. As with you, these vital signs are able to give the manager a quick look at the overall health of the plant. If the local manager only looked at the vital signs, he would have a better understanding of the health of his production process.
Vital signs are designed to be site-specific. One set of signs may perform well at one location but fail to produce the desired outcome at another location. The development of vital signs is a joint effort with the regional manager, local manager and the editor of the log.
Vital signs are short direct statements of performance. In order not to overwhelm the local manager, the vital signs need to be limited. I would like to suggest vital signs be limited to no more than five.
Vital signs are formatted as bullet points to keep the focus on the outcome. Each of the five vital signs is assigned a goal. The goal is a method that allows the manager to compare month-to-month or year-to-year. It also allows the manager, at a glance, to know the plant status.
To better understand what vital signs would look like, let’s examine a set of five in a fictitious plant. The information within the box is an example of how the data would be formatted, simple and straightforward.
1. Tons per man-hour: Tons shipped from the plant per site/shift. It is always better to use tons shipped and not tons produced. You only get credit for what you sell; everything else is waste.
Total days the plant open and operated: 22
Total nights the plant operated: 15
Crew size days: 3.5(average size) Crew size night: 3
Total man-hours per day, 35 per month 770 hours
Total man-hours per night, 24 per month 360 hours
Tons shipped / month day: 27,720
Tons shipped/month night: 13,068
Tons per man-hour per day: 36 Tons per man-hour per night: 36.3
Goal: 40 tons per man-hour per shift
2. Average production rate (shipped) as expressed as a percentage of maximum design of the plant. This is a new way to look at production tying it to the design rate of the plant. We all know that the design of the plant is a function of somewhat perfect conditions, in both the plant and raw materials used. By comparing the real world and the design, you may find areas for improvement.
Average TPH shipped/month: 360
Design production rate from the manufacture: 500 TPH
Rate calculated at: 72% of design
Goal 80% of design
3. Mix temp. vs Shipped temp. vs Jobsite temp. This sign goes to the heart of a problem many plants have. Operators tend to produce a mix that is too hot. The outcomes are placement problems, energy waste and loss of production.
Average Day Mix Discharge Temperature: 330F
Average Days Mix Shipped Temperature: 322F
Average Days Job Site Temperature: 305F
Average Nights Mix: 335F
Job Site: 315F
Goal Temp. at Job Site: 290F
4. Mix Changes per day/Start-ups per day. This vital sign drove me crazy as I watched the plant operator switch between mixes without a plan or shut down the plant prematurely. The act of a careless plant operator will cause additional waste, loss of production and result in a higher cost.
Average mix changes (Days): 6
Average start-ups: 3
Average mix changes (Night): 1
Average start-ups: 2
5. Uptime availability. This a term I have been using since the 80’s. It has always bothered me that I could not get this number into the 90th percentile range. Actions that contribute to loss of uptime can be unscheduled stoppage, breakdowns outside acceptable rates, or careless shipping schedules.
Average total shift hours: 10.5
Average total plant production hours: 7.5
Traditional summary reports have two major snags:
1. Time lag: In the real world, there is always a time lag. To better manage this time lag, The Log’s editor has the ability to interact with the plant manager as the data is being analyzed. An additional time delay happens if the manager does not make it a priority to review the report. Using the interactive aspect of The Log, the editor can notify the manager about the severity of the issue.
Data can become stale over time. A correction that may be simple to address, can become more difficult as time goes on. Because of the hot mix’s short shelf life, any correction in the production cycle needs to be followed up on as quickly as possible.
Old data does not energize the local manager to be challenged. How many of your plants have a burner control recorder (Real-time data collection)? Do you or your manager analyze the data on a daily basis? Or is the data filed without a care?
2. Ability to identify a questionable trend.
One definition of a trend is: “To have, or take, a particular direction.”
What is important to note is that all plants develop trends. Most are good, some, not so much. A trend could be something as simple as a habit; such as a setting that is just a bit off. It could also be something not noticed in the pressures of the day.
Examples that can cause, or affect a trend:
1. Attention to detail
Operators can be distracted by:
- Other crew members;
- Load out of trucks and generation of scale tags; and
- Inbound deliveries of raw materials for production.
*Phone calls, texts and social media are big distractions!
2. Comfort level
Most operators have a production rate that is within their comfort zone. This rate may be based of various factors:
Discharge temp: I have noticed within a given range, all operators seem to favour a certain temperature of mix, day in and day out;
Qualifications and experience of the operator;
- Distractions by additional required duties;
- Silo management: such things as how long to store, when to empty out the silo, and should you store over night?
- General traffic within the yard.
How confident are you that you or your manager will identify and act on a questionable trend? I believe, due to the nearness of the plant decisions and distractions going on during the operational day, a manager may have a tough time identifying and acting on suspected trends.
The Log editor has the advantage of space. He is one step removed from the day-to-day. The editor has the time to reflect. By design, a log-based documentation platform allows for a search of all trends. By overlaying various data reports and sources, a questionable trend may be spotted sooner rather than later by the editor.
Let me pose a question to you:
Can you reconstruct July 12, 2017? Was it a good day?
Did the plant run? What was the weather like? Did you suffer a breakdown, or other production run stoppage? I could go on and on, but the point is, could you provide documentation to reconstruct a given day in a timely manner?
Again, like a ship’s log, all significant elements of the day’s action are documented. The “plant report” form is vital to successful archiving. These plant reports, like other aspects of the log-based narrative are site-specific. The plant report is designed to be completed at the end of every shift. It should reflect the particular traits of the plant.
Again, I would like you to ask yourself if you are content with your plant reporting effort? Are you, like in the case of baseball, willing to chuck the status quo for the reward of improvement? I would like to think most of our industry would say, yes.
I can also guess what you are thinking: Change is no guarantee of improvement. To that, I would say, you’re right. However, is what you are providing today, meeting the needs of the local manager? Does providing a one size fits all summary report motivate the manager towards improvement? Are you confident that the manager will have the desire, and the ability, to harvest the report for insights into the operation?
A log-based platform gives the local manager the capability to focus on making the needed day-to-day decisions to keep “the ship” moving forward. By way of an interactive relationship with the log’s editor, the manager becomes more confident in his ability.
In Part 3, I will outline how to go forward to develop a log-based documentation platform that will work best for your company. You will find, it’s not as hard as you may think. If you have a system currently in place, the transformation can be simple and seamless. If you don’t have a system, or you want to scrap yours and start over, that can be done as well.
If you have any questions, please feel free to contact me at firstname.lastname@example.org.
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