In recent months, I’ve been working on a project to redesign a national training program for bulk plant employees in the propane industry. The material is being written at an 8th grade reading level and, for the most part, the training content is pretty straightforward. It covers topics like filling and emptying propane containers, and federal codes and regulations as they relate to the training tasks. And, of course, safety considerations are paramount when training folks to work with a flammable gas that can give you instant freeze burns in its liquid state. (Before I go any further, please note that propane is an extremely safe product when handled appropriately!)
So, no big deal, right? I mean, how hard can it be to explain how to safely fill or empty a propane container? As it turns out, not that hard in terms of procedural steps, but much harder than I expected in terms of how environmental conditions can impact the nuances of a procedure. Even better, it’s the feeling of my group of subject matter experts (a great group of guys with many years of experience in the industry) that you can’t really teach someone how to recognize the impact of environmental conditions that can create dangerous situations. Rather, it has to be learned through experience.
Now, experiential learning is great. It’s often the fastest way to cement something in memory, particularly if the experience was either very good or very bad. I think it is safe to say that anyone who has touched a hot stove (no matter how many times your Mom said not to) learned after only one experience not to do it again. The cause and effect is easy to understand.
Going back to the propane industry, there is a phenomenon called auto-refrigeration. In a nutshell, auto-refigeration happens when the demand on a system for propane vapor is higher than what can be replaced by the propane liquid boiling to create more vapor (propane boils at 44 degrees below zero). The result of the phenomenon is liquid propane becoming trapped in hoses or supply lines, waiting to splash and freeze burn some poor worker when they break the connection too soon. If you make this mistake and are lucky, the propane splashes on your work boots. If you are unlucky, it could splash your face resulting in serious injury or blindness. That would NOT be a good day at work.
The difference between the hot stove and auto-refrigeration is that with the stove, the danger is obvious (at least after you experience it once). You can see the flame at the burner or the electric element glowing red. With auto-refrigeration, the danger is not so obvious. In fact, it is downright elusive without an advanced degree in physics. The when, why and how of auto-refrigeration is a complex problem with a huge number of variables. It can arise, or not, in variety of situations with potentially serious consequences for inexperienced workers.
On the other hand, experienced workers develop a sort of sixth sense about when auto-refrigeration is likely to happen. They can’t really explain how they know, they just do. It is wisdom they have based on years of experience, and many near misses and minor injuries.
So, I am sure you see the problem here. How can we simplify a complex learning target like auto-refrigeration enough to give workers what they need to avoid injury until they have a chance to gain the wisdom of experience? We’ve come up with a couple of methods that I’d like to share.
First, instead of focusing on what happens inside the hose when auto-refrigeration occurs (which can’t be seen), we have chosen to focus on two ways that a new worker could be alerted that auto-refrigeration is taking place or is likely to happen.
- Frost forming on the outside of a hose or container is a fairly sure sign that auto-refrigerationis taking place, but you have to watch for this. With that in mind, we have incorporated steps in a variety of procedures to check for that frost.
- Auto-refrigeration is most likely to occur when temperatures outside are low, say below 40 degrees. This effects workers in northern states more often than in the south so we have made that point abundantly clear throughout the program.
Second, again instead of focusing primarily on the phenomenon itself, we have chosen to focus on what a worker can do to protect themselves every time they break a connection, whether auto-refrigeration is a factor or not. And what they can do is simple:
- Always break connections away from the face and body to avoid getting splashed should auto-refigeration happen.
- Always wear your personal protective equipment, including safety glasses, gloves and work boots.
While the workers may come to understand and anticipate auto-refrigeration through their experiences over many years in the field, we have simplified the learning target enough to keep them safe in the meantime. And that’s what it is really all about, isn’t it?





























