by John Terry
edited by Tom Hamilton
The following information was developed by John Terry, Saratoga, California. The article is based on one of his safety seminar presentations and has been edited for print. Editor.
This is my basic questionWhat do I look for when I get gloves and how much protection do gloves give me?
There are three applications or reasons that you wear gloves.
First, when handling ropes and it slides through your bare hands you know that it can get warm and can take the skin right off of your hand. I know of very few times when you are tethering a balloon or inflating a balloon that you should allow a rope to slip through your hands. There are some emergency situations where that is the case. Nice leather gloves work very well. I think that everybody has experienced the different between letting ropes slip through their hands with and without gloves on.
The second case is fire. I have not done any experiments on that, but I have thought about doing some experiments on the protection gloves gives should you have to reach into a fire.
The third reason is, and this is mostly for pilots and crew that work around the basket, protection from a cryogenic freeze burn.
The last item is what this experiment is aboutprotection gloves provide against a cryogenic freeze burn.
You could put a glove on your hand, open up a nice steady stream of liquid propane, put your hand in it, and see how good your glove is. That essentially is what I did. Only I did it a little more controlled.
In any experiment you want something that is repeatable. You should be able to do it every time and get exactly, or very closely, the same results.
I put together a piece of equipment that didn't use my hand for the test.
Finger/Glove testing apparatus.
The hose runs off to a tank of propane, liquid or vapor. It has a nice blast valve that I can open it up and is connected to a standard wide open propane hose line. Right here is the glove. This is a little frame with a spring arrangement on the back that holds the finger because when the propane comes out there is a fair amount of force. This holds this one finger in a very good position. This allowed me to conduct the experiments in a very controlled environment. It allowed to try a number of different gloves. Here was a wonderful tool to do that job with.
Four of the gloves tested:
Old red ball; new red ball; heavy leather glove; Tuff Duck glove use by propane dealers.
The problem is that did I want to stick my finger in the glove. I went to the Stanford Medical center and asked if they had any left over fingers, I want to use them in an experiment. They looked at me kind of funny and ushered me right out the side exit. I did the next best thing. I went down to my local grocery store and procured some Hebrew National all beef simulated fingers. It was suggested to me that I really didn't need real fingers, that these would do quite well.
How do you know when your, ugh, hot dog gets hurt? To determine whether my Hebrew National all beef finger was hurt I mounted in it a thermistor that is used for scientific and medical work. The thermistor is very small and fits right on the end of a probe. The thermistor is placed just under the surface of the simulated finger. I hooked this up to a temperature strip recorder. Now I am able to record the temperature at that point on the simulated finger.
On the recording strip the time elements where measured in one second increments. I was concerned with three specific temperatures, 99 degrees or body temperature, 32 degrees the freezing point, and minus 44 degrees the boiling point of propane. I set zero to the body temperature and turned on the propane.
In the first test we started at room temperature with just the thermistor, it wasn't heated. When the propane was turned on the temperature went down to minus 44 degrees in about a second and a half. This is the response of the recorder, as fast it could move. Actually in less than one-tenth of a second the finger was at minus 44 degrees. What that means is all water in the cells right at the surface of the finger had more than just froze.
I didn't like freezing the blood in my finger. That is why I choose 32 degrees and a benchmark in testing the gloves. I felt that keeping the temperature above that level is a pretty good criteria when looking for protection with your real hand. The temperature chart in the first experiment has a wavy line moving upward after the propane stream is turned off. It took quite a while for the propane to boil off. As that happened over time the finger warms up. It took about six seconds for the temperature to get back up to the freezing point. That was the start of experiment, the base experiment if you will.
I had a bundle load of gloves and did about 30 or 40 experiments and variations of experiments. I am not going to give you all of them but rather look at the highlights. You will get the idea of what is going on.
The next experiment I did was put the simulated finger on the testing machine with the thermistor. The curve falls a little bit slower. It didn't quite get down to minus 44 degrees but it did get the message through that just a bare finger in a liquid stream of propane didn't take long to freeze. If you get your bare hands in a liquid stream for one to two tenths of a second you are going to have a propane burn, you are going to have a freeze burn. I will talk more about the severity of freeze burns later. So I didn't want to stick my finger into a liquid propane stream. This was really no revelation before I did the experiment, but this gave the proof and the ability to show somebody what really happens.
The first glove I tried was an old favorite of mine. I doubt that there is anybody in ballooning who hasn't had a good pair of leather gloves. Nice and comfortable, soft, and does the job real well and shows lots signs of wear. I took my old gloves that I had been flying with for a number of years, I call them my red ball gloves because they have a red ball on the strap. I took them and put them on the machine with the simulated finger inside and turned the machine on with vapor. I decided the start with the stuff that wasn't quite as severe. What I found was that my leather glove gave about three seconds of protection from a vapor stream before the temperature went down to the freezing point of water.
Consider the valves that are on the tops of your propane tanks. How long does it takes to turn them off? The very old valves take about three and a half to four turns. Recent valves, last 10 to 12 years, take two turns to close. In three seconds I can get a two turn valve off pretty reliably if I know where the valve is and I don't have to go looking at it in this big cloud of propane vapor. Two seconds and it looks like my glove gives protection from vapor pretty well.
Then I got a new red ball glove and got real brave. I glued the heat thermistor to my finger and I put my hand in a nice new red ball glove. I cranked the valve on liquid for one second.
I learned a couple of things from this experiment. First, how to take a glove off very fast. I had little dotted lines along the side of my finger. Second thing I learned is that the liquid propane gets through the nice new seam on the glove, pocketing inside of the glove, and the glove holds it there. So when the propane came in through the seam boy did I take the glove off in a hurry. OK, its beginning to make sense now. The dots on my fingers is the liquid boiling off on the inside of the glove. So, I didn't do that quite a again.
I looked at some other gloves. I really didn't solve the problem of a gauntlet glove but I did test one. I tested a fireplace glove with much heavier leather. I wanted to test to see if the propane is not only getting through the seams but is it also getting through the pours of the leather. The results were about the same. Once the propane gets through the seams the curve drops off quickly. So the name of the game is how fast does the propane get through the seam, how good is the seam. This is the theme to examine.
I have not found any seam sealer that works very well or very long on leather.
I tested a rather nice thick leather glove that you might use in the laundry when you didn't want to get your hand in this gunky stuff. Now here I thought is something that didn't have any seams in it. It is all rubber coated and in great shape.
I turned the liquid stream on for six seconds with a human finger in the glove and I was in great shape. I did the experiment first with the simulated finger. It looked great, it looked like this is the answer, the glove looked like hell, but it looked like it did the job.
Then I found another problem. At the end of the six seconds I couldn't move my fingers. I had a cast iron glove. I couldn't shut the valve off if my life depended on it because of a frozen rubber glove. So there is one idea that went flat.
Next I went down to my local propane store and asked what did they use for gloves. They said that they are suppose to use Tuff Duck, made by a company in Thig Pen, Alabama. One characteristic of these gloves is a plastic coating around the seams. In fact, it has two of these plastic coating together in a seam. So maybe that will work pretty good. The seams are rapped around to the back side.
I tested this one in liquid stream for 17 seconds. The glove protected pretty well. As far as I am concerned this provides the best protection that is available today in a glove.
The downside? It is horrible to wear. It is not like leather, the glove does not breath. Your hand is sweating in about five minutes. I conducted the test right after putting my hand in the glove and before my hand started perspiring.
This glove does provide reasonable protection. You can take and get your hand in a liquid stream and get the valve turned off and not be totally disastrous. The glove stays reasonably flexible. It does get stiffer but the plastic coating is thinner.
At propane store and I found that the guys had been wearing their gloves about eight months to long. They were kind of shredded. They were wearing gloves because some manager said to wear gloves. They were long past the point where they were going to provide the protection that my testing demonstrated. Of course, with all the holes the gloves were more comfortable.
The conclusion that I came to is that I will continue to wear the nice comfortable kind of leather gloves that I like to wear. They will give me about half to one second protection in a liquid stream. I will have about three to four seconds in vapor. If I wear a specialty glove like the Winter Tuff Duck I can get noticeably longer protection. I carry these better gloves so that when I am in a high risk situation, like refueling, then I wear the Tuff Duck. When I am going to wear something for an hour then I go back and wear the comfortable leather glove and realize that I am doing a cost/performance evaluation. I am evaluating what is the probability that I am going to have to stick my hand into liquid propane in the next hour. Am I going to be comfortable versus am I going to be extremely uncomfortable wearing the other glove.
Some more conclusions. I now include some things in my emergency training such as practicing shutting off fuel tanks without looking at them. Turn my back on them, do I know where I can put my hand and turn that tank off. If there is a liquid valve with a bad leak around it I am not going to be able to see it. I want to be able to get to that valve and know right where it is and get my hands on it and practice on getting that glove off in one hell of a hurry.
I went to NASA, I figured if anybody has data on cryogenic burns it is NASA. I got the cold shoulder, especially when they found out that I was not willing to pay money for the information.
I did a general literature search and came up with a research report from three doctors at the University of Alaska. They did research that is extremely relevant to this subject. They had an almost unlimited supply of people to try out various ideas on.
In Alaska it is 30 below out most of the time in the winter. Most of the miners and oil workers, after they get off work, go down to the local bar and when they get their blood alcohol level to a point that is sufficient they wander out of the bar and fall down within a block. Eventually they are found and carried into the hospital. A perpetual stream of people coming in with very serious cold burns, frostbite. The doctors tried a number of experiments.
They came up with a list of things that you are suppose to do like put snow on it etc. They tried all of these methods. What they found is some treatments have a significantly higher recovery rate.
With frostbite, or the cryogenic burn, 75 percent of the water in your body is subject to being converted to ice crystals. This causes quite a bit of physical damage to the cells. The cells can expand a certain amount but ice crystal seems to take and break cell boundaries. That is where part of the problem is.. Right after the body thaws there is chemical imbalances that occur in the blood due to low temperature. This results in improper control of the membrane transfers of fluid through cell walls. Severity of the problem can be difficult to ascertain from the symptoms of the freeze burn.
Anybody who has a propane burn develops a set of responses. The first 15 or 20 minutes not too much happens, spots begin to appear. After that it begins to ache and hurt, maybe as late as 30 minutes after. Whether you are lightly burned or heavily burned the response is about the same. There is nothing in the first couple of hours that tells how severely you are burned. What you have to do is have the experience of the environment that you were in. My hand was in a liquid stream for half a second, or three seconds. If you experience a three second exposure you are in bad trouble, real bad trouble.
The level of cryogenic frostbite varies from next day to three day. This really has to do with normal thawing, the period of normal feeling returning. Also, how much pain there is. Sometimes the pain is so bad that you can't sleep. If you have trouble sleeping that night you probably had a two to three day burn. If the pain is light it will probably itch a little bit.
The last stage is blisters forming. If you have a cryogenic burn where blisters form, usually within two hours, see a doctor. The doctor can't do very much about it. But, what he can do is very important. There is a very high probability of infection setting in. Your skin is going to break. The first thing that he is going to do is thoroughly clean the wound with an antiseptic and put something on there that is going to prevent other germs from getting in. He will then say take two aspirins and call me tomorrow. Whatever your pain killer of choice is there is nothing much beyond that they can do.
The best method to thaw the frozen area discovered by the Alaska study is to put the body part effected in a controlled 105 degree temperature environment and keep it there. Do not let it get hotter than 108 degrees. When people came in they would strip them down and put them in the bath tub until the effected area was thoroughly brought up to the 105 to 108 degree temperature, pull them out, dry them off, and look for blisters or other signs.
How many balloon fields have you seen with one of these controlled temperature bath tubs? I have talked with first aid people to get their opinion. About the only thing that you have out in the field that is applicable is your arm pit or between your legs. That is 95 to 98 degrees and that is about as good as you are going to do.
A lot of the old wives tales don't work. Don't put the hair dryer on it or fan it in front of the burner. Heat is transmitted in three different ways; conduction, convection and radiation. Conduction is when you are holding onto a copper bar and you put the other end into a fire. Pretty soon you drop the copper bar because the heat from the fire is being conducted along it. Convection is like the furnace in your home. The air is heated up and once it is hot moves through the pipes and is thrown at you through the registers. Air is a rather poor conductor. Radiation will have a source of heat radiated through the medium without heating the medium up. It is like turning the burner on and warming your hands. The air in-between is not being heated very well. With radiation it is very easy to overheat. Stay away from radiation. The best method for warming up the area frozen is to use conducted heat within the specified temperature limits.
Snow and cold water doesn't work. Rubbing to bring in circulation doesn't work, the skin is so cold at that particular time that it has no flexibility or the ability to move and you are just rubbing skin away. Don't allow the effected area to refreeze. Don't smoke, don't drink alcohol, don't apply ointments. After thawing keeping the effected area dry and warm, body temperature. Keep clothing from rubbing the area. Inspect frequently the next 24 hours for blisters. Contact your doctor.